201
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Laish I, Mannasse-Green B, Hadary R, Konikoff FM, Amiel A, Kitay-Cohen Y. Aneuploidy and asynchronous replication in non-alcholic fatty liver disease and cryptogenic cirrhosis. Gene 2016; 593:162-166. [PMID: 27520584 DOI: 10.1016/j.gene.2016.08.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 07/24/2016] [Accepted: 08/08/2016] [Indexed: 12/25/2022]
Abstract
BACKGROUND/AIMS Non-alcoholic fatty liver disease (NAFLD) and cryptogenic cirrhosis (CC), which is largely a late sequela of NAFLD, are considered pre-neoplastic conditions that might progress to hepatocellular carcinoma. Aneuploidy, telomere aggregates and synchronization of replication were evaluated as markers of genetic instability in these patients. METHODOLOGY Peripheral blood lymphocytes from 22 patients with NAFLD, 20 patients with CC and 20 age-matched healthy controls were analyzed. To determine random aneuploidy, we used the fluorescence in situ hybridization (FISH) with probes for chromosomes 9 and 18. The rate of aneuploidy was inferred from the fraction of cells revealing one, three or more hybridization signals per cell. Aggregate size was divided into three fusion groups of 2-5, 6-10 and 11-15 telomeres, relative to the size of a single telomere. The replication pattern was determined by FISH in two pairs of alleles, 15qter and 13qter. Asynchrony was determined by the presence of one single and one set of double dots in the same cell. RESULTS Significantly higher random aneuploidy rate was found in the CC patients than in the control group, and to a lesser degree in NAFLD patients. Telomere aggregates were insignificantly higher in both groups. Only patients with CC showed significantly higher rate of asynchronous replication with proportionately more cells with two single dots among the normal cells (p<0.001). CONCLUSIONS These results likely reflect changes in gene replication and cell cycle progression in these conditions, possibly correlating with their malignant potential.
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Affiliation(s)
- Ido Laish
- Gastroenterology and Hepatology Institute, Meir Medical Center, Kfar Saba, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | | | - Ruth Hadary
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel; Liver Unit, Meir Medical Center, Kfar Saba, Israel
| | - Fred M Konikoff
- Gastroenterology and Hepatology Institute, Meir Medical Center, Kfar Saba, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Aliza Amiel
- Genetic Institute, Meir Medical Center, Kfar Saba, Israel; Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel
| | - Yona Kitay-Cohen
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel; Liver Unit, Meir Medical Center, Kfar Saba, Israel
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202
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Telomerase: The Devil Inside. Genes (Basel) 2016; 7:genes7080043. [PMID: 27483324 PMCID: PMC4999831 DOI: 10.3390/genes7080043] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/23/2016] [Accepted: 07/25/2016] [Indexed: 01/04/2023] Open
Abstract
High telomerase activity is detected in nearly all human cancers but most human cells are devoid of telomerase activity. There is well-documented evidence that reactivation of telomerase occurs during cellular transformation. In humans, tumors can rely in reactivation of telomerase or originate in a telomerase positive stem/progenitor cell, or rely in alternative lengthening of telomeres, a telomerase-independent telomere-length maintenance mechanism. In this review, we will focus on the telomerase positive tumors. In this context, the recent findings that telomerase reverse transcriptase (TERT) promoter mutations represent the most common non-coding mutations in human cancer have flared up the long-standing discussion whether cancer originates from telomerase positive stem cells or telomerase reactivation is a final step in cellular transformation. Here, we will discuss the pros and cons of both concepts in the context of telomere length-dependent and telomere length-independent functions of telomerase. Together, these observations may provoke a re-evaluation of telomere and telomerase based therapies, both in telomerase inhibition for cancer therapy and telomerase activation for tissue regeneration and anti-ageing strategies.
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203
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Platform Presentations. Toxicol Pathol 2016. [DOI: 10.1177/019262339302100612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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204
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Trump BF. Mechanisms of Toxicity and Carcinogenesis. Toxicol Pathol 2016. [DOI: 10.1177/019262339502300616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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205
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Panarese S, Brunetti B, Sarli G. Evaluation of Telomerase in Canine Mammary Tissues by Immunohistochemical Analysis and a Polymerase Chain Reaction-Based Enzyme-Linked Immunosorbent Assay. J Vet Diagn Invest 2016; 18:362-8. [PMID: 16921875 DOI: 10.1177/104063870601800407] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
The enzyme telomerase is considered a potential marker for neoplastic tissue and is used as a diagnostic and prognostic tool in clinical medicine and therapeutics. For this reason, the possible role of telomerase activation in the process of malignant transformation is currently the subject of intense research efforts. The focus of the study reported here was to detect telomerase in 37 canine mammary samples, by comparing two methods: immunohistochemical (IHC) analysis for detecting the catalytic subunit of the enzyme, telomerase reverse transcriptase (TERT), and the telomeric repeat amplification protocol–enzyme-linked immunosorbent assay (TRAP-ELISA), a polymerase chain reaction (PCR)-based technique that uses a colorimetric detection method. Using the TRAP-ELISA, samples were considered positive when they yielded a difference of at least 0.2 absorbance units between the readings at 450 nm versus 690 nm wavelength. On the basis of this criterion, 18 negative and 19 positive cases were obtained. Specific immunohistochemical staining was observed mainly in the nucleoli, to a lesser extent in the nuclei, and rarely in the cytoplasm of epithelial cells. A sample was considered positive when at least 10% of the epithelial cells had specific staining. The Pearson correlation between the TRAP-ELISA and IHC results was significant only when IHC nucleolar ( r = 0.53, P < 0.01) or nuclear ( r = 0.36, P < 0.05) staining or their combination ( r = 0.58, P < 0.01) was considered. Thus, IHC staining of nucleoli and nuclei can be considered as an alternative method to the TRAP-ELISA. The detection of telomerase in normal mammary gland and fibrocystic mastopathy using both methods does not support the idea that telomerase may be used as a specific marker of mammary neoplasia in dogs.
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Affiliation(s)
- Serena Panarese
- Department of Veterinary Public Health and Animal Pathology, Section of General Pathology and Pathologic Anatomy, Faculty of Veterinary Medicine, University of Bologna Via Tolara di Sopra, 50-40064, Ozzano dell'Emilia, Bologna, Italy
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206
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Abstract
UNLABELLED Telomeres progressively shorten throughout life. A hallmark of advanced malignancies is the ability for continuous cell divisions that almost universally correlates with the stabilization of telomere length by the reactivation of telomerase. The repression of telomerase and shorter telomeres in humans may have evolved, in part, as an anticancer protection mechanism. Although there is still much we do not understand about the regulation of telomerase, it remains a very attractive and novel target for cancer therapeutics. This review focuses on the current state of advances in the telomerase area, identifies outstanding questions, and addresses areas and methods that need refinement. SIGNIFICANCE Despite many recent advances, telomerase remains a challenging target for cancer therapy. There are few telomerase-directed therapies, and many of the assays used to measure telomeres and telomerase have serious limitations. This review provides an overview of the current state of the field and how recent advances could affect future research and treatment approaches. Cancer Discov; 6(6); 584-93. ©2016 AACR.
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Affiliation(s)
- Jerry W Shay
- Department of Cell Biology, The University of Texas Southwestern Medical Center, Dallas, Texas. Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.
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207
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Aminizadeh N, Tiraihi T, Mesbah-Namin SA, Taheri T. Stimulation of cell proliferation by glutathione monoethyl ester in aged bone marrow stromal cells is associated with the assistance of TERT gene expression and telomerase activity. In Vitro Cell Dev Biol Anim 2016; 52:772-81. [DOI: 10.1007/s11626-016-0021-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 03/23/2016] [Indexed: 01/08/2023]
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208
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Udomsinprasert W, Kitkumthorn N, Mutirangura A, Chongsrisawat V, Poovorawan Y, Honsawek S. Global methylation, oxidative stress, and relative telomere length in biliary atresia patients. Sci Rep 2016; 6:26969. [PMID: 27243754 PMCID: PMC4886632 DOI: 10.1038/srep26969] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/11/2016] [Indexed: 12/25/2022] Open
Abstract
Alu and LINE-1 elements are retrotransposons with a ubiquitous presence in the human genome that can cause genomic instability, specifically relating to telomere length. Genotoxic agents may induce methylation of retrotransposons, in addition to oxidative DNA damage in the form of 8-hydroxy-2′-deoxyguanosine (8-OHdG). Methylation of retrotransposons induced by these agents may contribute to biliary atresia (BA) etiology. Here, we investigated correlations between global methylation, 8-OHdG, and relative telomere length, as well as reporting on Alu and LINE-1 hypomethylation in BA patients. Alu and LINE-1 hypomethylation were found to be associated with elevated risk of BA (OR = 4.07; 95% CI: 2.27–7.32; P < 0.0001 and OR = 3.51; 95% CI: 1.87–6.59; P < 0.0001, respectively). Furthermore, LINE-1 methylation was associated with liver stiffness in BA patients (β coefficient = −0.17; 95% CI: −0.24 to −0.10; P < 0.0001). Stratified analysis revealed negative correlations between Alu and LINE-1 methylation and 8-OHdG in BA patients (P < 0.0001). In contrast, positive relationships were identified between Alu and LINE-1 methylation and relative telomere length in BA patients (P < 0.0001). These findings suggest that retrotransposon hypomethylation is associated with plasma 8-OHdG and telomere length in BA patients.
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Affiliation(s)
- Wanvisa Udomsinprasert
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
| | - Nakarin Kitkumthorn
- Department of Oral and Biology, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
| | - Apiwat Mutirangura
- Center of Excellence in Molecular Genetics of Cancer and Human Diseases, Department of Anatomy, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Voranush Chongsrisawat
- Center of Excellence in Clinical Virology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Yong Poovorawan
- Center of Excellence in Clinical Virology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Sittisak Honsawek
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
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209
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Luo D, Mu Y. Computational Insights into the Stability and Folding Pathways of Human Telomeric DNA G-Quadruplexes. J Phys Chem B 2016; 120:4912-26. [DOI: 10.1021/acs.jpcb.6b01919] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Di Luo
- School
of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Yuguang Mu
- School
of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
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210
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Abstract
INTRODUCTION Telomerase is a ribonucleoprotein that catalyses the addition of telomeric repeat sequences (having the sequence 5'-TTAGGG-3' in humans) to the ends of chromosomes. Telomerase activity is detected in most types of human tumours, but it is almost undetectable in normal somatic cells. Therefore, telomerase is a promising therapeutic target. To date, the known inhibitors of telomerase include nucleoside analogues, oligonucleotides and G-quadruplex stabilizers. This review highlights recent advances in our understanding of telomerase inhibitors, the relationships between telomerase inhibitors, cancer, and fields such as inflammation. AREAS COVERED This review summarizes new patents published on telomerase inhibitors from 2010 to 2015. EXPERT OPINION The review provides a brief account of the background, development, and on-going issues involving telomerase inhibitors. In particular, this review emphasizes imetelstat (GRN163L) and some typical G-quadruplex stabilizers that participate in telomerase inhibition. Overall, the research scope of antineoplastic is becoming broader and telomerase inhibitors have been shown to be a promising therapeutic target. Therefore, novel antineoplastic agents with greater activity and higher specificity must be developed.
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Affiliation(s)
- Ruo-Jun Man
- a State Key Laboratory of Pharmaceutical Biotechnology , Nanjing University , Nanjing , People's Republic of China.,b Preparatory College Education , Guangxi University for Nationalities , Nanning , People's Republic of China
| | - Long-Wang Chen
- a State Key Laboratory of Pharmaceutical Biotechnology , Nanjing University , Nanjing , People's Republic of China
| | - Hai-Liang Zhu
- a State Key Laboratory of Pharmaceutical Biotechnology , Nanjing University , Nanjing , People's Republic of China
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211
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Liddiard K, Ruis B, Takasugi T, Harvey A, Ashelford KE, Hendrickson EA, Baird DM. Sister chromatid telomere fusions, but not NHEJ-mediated inter-chromosomal telomere fusions, occur independently of DNA ligases 3 and 4. Genome Res 2016; 26:588-600. [PMID: 26941250 PMCID: PMC4864465 DOI: 10.1101/gr.200840.115] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 03/02/2016] [Indexed: 01/26/2023]
Abstract
Telomeres shorten with each cell division and can ultimately become substrates for nonhomologous end-joining repair, leading to large-scale genomic rearrangements of the kind frequently observed in human cancers. We have characterized more than 1400 telomere fusion events at the single-molecule level, using a combination of high-throughput sequence analysis together with experimentally induced telomeric double-stranded DNA breaks. We show that a single chromosomal dysfunctional telomere can fuse with diverse nontelomeric genomic loci, even in the presence of an otherwise stable genome, and that fusion predominates in coding regions. Fusion frequency was markedly increased in the absence of TP53 checkpoint control and significantly modulated by the cellular capacity for classical, versus alternative, nonhomologous end joining (NHEJ). We observed a striking reduction in inter-chromosomal fusion events in cells lacking DNA ligase 4, in contrast to a remarkably consistent profile of intra-chromosomal fusion in the context of multiple genetic knockouts, including DNA ligase 3 and 4 double-knockouts. We reveal distinct mutational signatures associated with classical NHEJ-mediated inter-chromosomal, as opposed to alternative NHEJ-mediated intra-chromosomal, telomere fusions and evidence for an unanticipated sufficiency of DNA ligase 1 for these intra-chromosomal events. Our findings have implications for mechanisms driving cancer genome evolution.
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Affiliation(s)
- Kate Liddiard
- Institute of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, United Kingdom
| | - Brian Ruis
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | - Taylor Takasugi
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | - Adam Harvey
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | - Kevin E Ashelford
- Institute of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, United Kingdom
| | - Eric A Hendrickson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | - Duncan M Baird
- Institute of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, United Kingdom
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212
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Abstract
The unlimited proliferation of cancer cells requires a mechanism to prevent telomere shortening. Alternative Lengthening of Telomeres (ALT) is an homologous recombination-mediated mechanism of telomere elongation used in tumors, including osteosarcomas, soft tissue sarcoma subtypes, and glial brain tumors. Mutations in the ATRX/DAXX chromatin remodeling complex have been reported in tumors and cell lines that use the ALT mechanism, suggesting that ATRX may be an ALT repressor. We show here that knockout or knockdown of ATRX in mortal cells or immortal telomerase-positive cells is insufficient to activate ALT. Notably, however, in SV40-transformed mortal fibroblasts ATRX loss results in either a significant increase in the proportion of cell lines activating ALT (instead of telomerase) or in a significant decrease in the time prior to ALT activation. These data indicate that loss of ATRX function cooperates with one or more as-yet unidentified genetic or epigenetic alterations to activate ALT. Moreover, transient ATRX expression in ALT-positive/ATRX-negative cells represses ALT activity. These data provide the first direct, functional evidence that ATRX represses ALT.
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213
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Cancer-specific binary expression system activated in mice by bacteriophage HK022 Integrase. Sci Rep 2016; 6:24971. [PMID: 27117628 PMCID: PMC4846993 DOI: 10.1038/srep24971] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/07/2016] [Indexed: 12/01/2022] Open
Abstract
Binary systems based on site-specific recombination have been used for tumor specific transcription targeting of suicide genes in animal models. In these binary systems a site specific recombinase or integrase that is expressed from a tumor specific promoter drives tumor specific expression of a cytotoxic gene. In the present study we developed a new cancer specific binary expression system activated by the Integrase (Int) of the lambdoid phage HK022. We demonstrate the validity of this system by the specific expression of a luciferase (luc) reporter in human embryonic kidney 293T (HEK293T) cells and in a lung cancer mouse model. Due to the absence viral vectors and of cytotoxicity the Int based binary system offers advantages over previously described counterparts and may therefore be developed into a safer cancer cell killing system.
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214
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Rice C, Skordalakes E. Structure and function of the telomeric CST complex. Comput Struct Biotechnol J 2016; 14:161-7. [PMID: 27239262 PMCID: PMC4872678 DOI: 10.1016/j.csbj.2016.04.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/06/2016] [Accepted: 04/07/2016] [Indexed: 11/25/2022] Open
Abstract
Telomeres comprise the ends of eukaryotic chromosomes and are essential for cell proliferation and genome maintenance. Telomeres are replicated by telomerase, a ribonucleoprotein (RNP) reverse transcriptase, and are maintained primarily by nucleoprotein complexes such as shelterin (TRF1, TRF2, TIN2, RAP1, POT1, TPP1) and CST (Cdc13/Ctc1, Stn1, Ten1). The focus of this review is on the CST complex and its role in telomere maintenance. Although initially thought to be unique to yeast, it is now evident that the CST complex is present in a diverse range of organisms where it contributes to genome maintenance. The CST accomplishes these tasks via telomere capping and by regulating telomerase and DNA polymerase alpha-primase (polα-primase) access to telomeres, a process closely coordinated with the shelterin complex in most organisms. The goal of this review is to provide a brief but comprehensive account of the diverse, and in some cases organism-dependent, functions of the CST complex and how it contributes to telomere maintenance and cell proliferation.
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215
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Gleich A, Kaiser B, Schumann J, Fuhrmann H. Establishment and characterisation of a novel bovine SV40 large T-antigen-transduced foetal hepatocyte-derived cell line. In Vitro Cell Dev Biol Anim 2016; 52:662-72. [DOI: 10.1007/s11626-016-0018-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/16/2016] [Indexed: 12/12/2022]
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216
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West MD, Binette F, Larocca D, Chapman KB, Irving C, Sternberg H. The germline/soma dichotomy: implications for aging and degenerative disease. Regen Med 2016; 11:331-4. [DOI: 10.2217/rme-2015-0033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Human somatic cells are mortal due in large part to telomere shortening associated with cell division. Limited proliferative capacity may, in turn, limit response to injury and may play an important role in the etiology of age-related pathology. Pluripotent stem cells cultured in vitro appear to maintain long telomere length through relatively high levels of telomerase activity. We propose that the induced reversal of cell aging by transcriptional reprogramming, or alternatively, human embryonic stem cells engineered to escape immune surveillance, are effective platforms for the industrial-scale manufacture of young cells for the treatment of age-related pathologies. Such cell-based regenerative therapies will require newer manufacturing and delivery technologies to insure highly pure, identified and potent pluripotency-based therapeutic formulations.
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Affiliation(s)
- Michael D West
- BioTime, Inc., 1010 Atlantic Ave., Alameda, CA 94501, USA
| | | | | | | | | | - Hal Sternberg
- BioTime, Inc., 1010 Atlantic Ave., Alameda, CA 94501, USA
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217
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Bell RJA, Rube HT, Xavier-Magalhães A, Costa BM, Mancini A, Song JS, Costello JF. Understanding TERT Promoter Mutations: A Common Path to Immortality. Mol Cancer Res 2016; 14:315-23. [PMID: 26941407 PMCID: PMC4852159 DOI: 10.1158/1541-7786.mcr-16-0003] [Citation(s) in RCA: 201] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 02/24/2016] [Indexed: 12/23/2022]
Abstract
Telomerase (TERT) activation is a fundamental step in tumorigenesis. By maintaining telomere length, telomerase relieves a main barrier on cellular lifespan, enabling limitless proliferation driven by oncogenes. The recently discovered, highly recurrent mutations in the promoter of TERT are found in over 50 cancer types, and are the most common mutation in many cancers. Transcriptional activation of TERT, via promoter mutation or other mechanisms, is the rate-limiting step in production of active telomerase. Although TERT is expressed in stem cells, it is naturally silenced upon differentiation. Thus, the presence of TERT promoter mutations may shed light on whether a particular tumor arose from a stem cell or more differentiated cell type. It is becoming clear that TERT mutations occur early during cellular transformation, and activate the TERT promoter by recruiting transcription factors that do not normally regulate TERT gene expression. This review highlights the fundamental and widespread role of TERT promoter mutations in tumorigenesis, including recent progress on their mechanism of transcriptional activation. These somatic promoter mutations, along with germline variation in the TERT locus also appear to have significant value as biomarkers of patient outcome. Understanding the precise molecular mechanism of TERT activation by promoter mutation and germline variation may inspire novel cancer cell-specific targeted therapies for a large number of cancer patients.
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Affiliation(s)
- Robert J A Bell
- Department of Neurological Surgery, University of California, San Francisco, California
| | - H Tomas Rube
- Department of Biological Sciences, Columbia University, New York, New York
| | - Ana Xavier-Magalhães
- Department of Neurological Surgery, University of California, San Francisco, California. Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal. ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Braga, Portugal
| | - Bruno M Costa
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal. ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Braga, Portugal
| | - Andrew Mancini
- Department of Neurological Surgery, University of California, San Francisco, California
| | - Jun S Song
- Departments of Bioengineering and Physics, University of Illinois, Urbana-Champaign, Illinois
| | - Joseph F Costello
- Department of Neurological Surgery, University of California, San Francisco, California.
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218
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Sawhney V, Campbell N, Brouilette S, Coppen S, Harbo M, Baker V, Ikebe C, Shintani Y, Hunter R, Dhinoja M, Johnston A, Earley M, Sporton S, Bendix L, Suzuki K, Schilling R. Telomere shortening and telomerase activity in ischaemic cardiomyopathy patients – Potential markers of ventricular arrhythmia. Int J Cardiol 2016; 207:157-63. [DOI: 10.1016/j.ijcard.2016.01.066] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 12/09/2015] [Accepted: 01/01/2016] [Indexed: 11/25/2022]
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219
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Maurya PK, Noto C, Rizzo LB, Rios AC, Nunes SOV, Barbosa DS, Sethi S, Zeni M, Mansur RB, Maes M, Brietzke E. The role of oxidative and nitrosative stress in accelerated aging and major depressive disorder. Prog Neuropsychopharmacol Biol Psychiatry 2016; 65:134-44. [PMID: 26348786 DOI: 10.1016/j.pnpbp.2015.08.016] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 08/29/2015] [Accepted: 08/30/2015] [Indexed: 12/29/2022]
Abstract
Major depressive disorder (MDD) affects millions of individuals and is highly comorbid with many age associated diseases such as diabetes mellitus, immune-inflammatory dysregulation and cardiovascular diseases. Oxidative/nitrosative stress plays a fundamental role in aging, as well as in the pathogenesis of neurodegenerative/neuropsychiatric disorders including MDD. In this review, we critically review the evidence for an involvement of oxidative/nitrosative stress in acceleration of aging process in MDD. There are evidence of the association between MDD and changes in molecular mechanisms involved in aging. There is a significant association between telomere length, enzymatic antioxidant activities (SOD, CAT, GPx), glutathione (GSH), lipid peroxidation (MDA), nuclear factor κB, inflammatory cytokines with MDD. Major depression also is characterized by significantly lower concentration of antioxidants (zinc, coenzyme Q10, PON1). Since, aging and MDD share a common biological base in their pathophysiology, the potential therapeutic use of antioxidants and anti-aging molecules in MDD could be promising.
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Affiliation(s)
- Pawan Kumar Maurya
- Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Universidade Federal de São Paulo, São Paulo, Brazil; Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Cristiano Noto
- Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Lucas B Rizzo
- Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Universidade Federal de São Paulo, São Paulo, Brazil; Department of Psychiatry, Clinic for Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Adiel C Rios
- Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Sandra O V Nunes
- Graduation Program in Health Sciences, Universidade Estadual de Londrina, Londrina, PR, Brazil
| | - Décio Sabbatini Barbosa
- Graduation Program in Health Sciences, Universidade Estadual de Londrina, Londrina, PR, Brazil
| | - Sumit Sethi
- Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Maiara Zeni
- Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Rodrigo B Mansur
- Mood Disorders Psychopharmacology Unit (MDPU), University Health Network (UHN), University of Toronto, Toronto, Canada
| | - Michael Maes
- Graduation Program in Health Sciences, Universidade Estadual de Londrina, Londrina, PR, Brazil; Department of Psychiatry, Chulalongkorn University, Bangkok, Thailand
| | - Elisa Brietzke
- Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Universidade Federal de São Paulo, São Paulo, Brazil.
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220
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Abstract
Telomeres, the protective ends of linear chromosomes, shorten throughout an individual's lifetime. Telomere shortening is a hallmark of molecular aging and is associated with premature appearance of diseases associated with aging. Here, we discuss the role of telomere shortening as a direct cause for aging and age-related diseases. In particular, we draw attention to the fact that telomere length influences longevity. Furthermore, we discuss intrinsic and environmental factors that can impact on human telomere erosion. Finally, we highlight recent advances in telomerase-based therapeutic strategies for the treatment of diseases associated with extremely short telomeres owing to mutations in telomerase, as well as age-related diseases, and ultimately aging itself.
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Affiliation(s)
- Christian Bär
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
| | - Maria A Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
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221
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Uziel O, Yerushalmi R, Zuriano L, Naser S, Beery E, Nordenberg J, Lubin I, Adel Y, Shepshelovich D, Yavin H, Aharon IB, Pery S, Rizel S, Pasmanik-Chor M, Frumkin D, Lahav M. BRCA1/2 mutations perturb telomere biology: characterization of structural and functional abnormalities in vitro and in vivo. Oncotarget 2016; 7:2433-54. [PMID: 26515461 PMCID: PMC4823046 DOI: 10.18632/oncotarget.5693] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 10/06/2015] [Indexed: 01/12/2023] Open
Abstract
BRCA1 mutation is associated with carcinogenesis, especially of breast tissue. Telomere maintenance is crucial for malignant transformation. Being a part of the DNA repair machinery, BRCA1 may be implicated in telomere biology. We explored the role of BRCA1 in telomere maintenance in lymphocytes of BRCA1/2 mutation carriers and in in vitro system by knocking down its expression in non-malignant breast epithelial cells.The results in both systems were similar. BRCA1/2 mutation caused perturbation of telomere homeostasis, shortening of the single stranded telomere overhang and increased the intercellular telomere length variability as well as the number of telomere free chromosomal ends and telomeric circles. These changes resulted in an increased DNA damage status. Telomerase activity, inducibility and expression remained unchanged. BRCA1 mutation resulted also in changes in the binding of shelterin proteins to telomeres. DNMT-1 levels were markedly reduced both in the carriers and in in vitro system. The methylation pattern of the sub-telomeric regions in carriers suggested hypomethylation in chromosome 10. The expression of a distinct set of genes was also changed, some of which may relate to pre-disposition to malignancy.These results show that BRCA gene products have a role in telomere length homeostasis. It is plausible that these perturbations contribute to malignant transformation in BRCA mutants.
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Affiliation(s)
- Orit Uziel
- The Felsenstein Medical Research Center, Beilinson Medical Center, Tel-Aviv University, Tel-Aviv, Israel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Rinat Yerushalmi
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Institute of Oncology, Davidoff Cancer Center, Beilinson Medical Center, Tel-Aviv University, Tel-Aviv, Israel
| | - Lital Zuriano
- The Felsenstein Medical Research Center, Beilinson Medical Center, Tel-Aviv University, Tel-Aviv, Israel
| | - Shaden Naser
- The Felsenstein Medical Research Center, Beilinson Medical Center, Tel-Aviv University, Tel-Aviv, Israel
| | - Einat Beery
- The Felsenstein Medical Research Center, Beilinson Medical Center, Tel-Aviv University, Tel-Aviv, Israel
| | - Jardena Nordenberg
- The Felsenstein Medical Research Center, Beilinson Medical Center, Tel-Aviv University, Tel-Aviv, Israel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Ido Lubin
- The Felsenstein Medical Research Center, Beilinson Medical Center, Tel-Aviv University, Tel-Aviv, Israel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Yonatan Adel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Internal Medicine A, Beilinson Medical Center, Petah Tikva, Israel
| | - Daniel Shepshelovich
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Internal Medicine A, Beilinson Medical Center, Petah Tikva, Israel
| | - Hagai Yavin
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Internal Medicine A, Beilinson Medical Center, Petah Tikva, Israel
| | - Irit Ben Aharon
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Institute of Oncology, Davidoff Cancer Center, Beilinson Medical Center, Tel-Aviv University, Tel-Aviv, Israel
| | - Shlomit Pery
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Institute of Oncology, Davidoff Cancer Center, Beilinson Medical Center, Tel-Aviv University, Tel-Aviv, Israel
| | - Shulamit Rizel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Institute of Oncology, Davidoff Cancer Center, Beilinson Medical Center, Tel-Aviv University, Tel-Aviv, Israel
| | - Metsada Pasmanik-Chor
- Bioinformatics Unit, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | | | - Meir Lahav
- The Felsenstein Medical Research Center, Beilinson Medical Center, Tel-Aviv University, Tel-Aviv, Israel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Institute of Hematology, Davidoff Cancer Center, Beilinson Medical Center, Petah Tikva, Israel
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Platinum(II) phenanthroimidazole G-quadruplex ligand induces selective telomere shortening in A549 cancer cells. Biochimie 2015; 121:287-97. [PMID: 26724375 DOI: 10.1016/j.biochi.2015.12.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 12/23/2015] [Indexed: 11/21/2022]
Abstract
Telomere maintenance, achieved by the binding of protective shelterin capping proteins to telomeres and by either telomerase or a recombination-based alternative lengthening of telomere (ALT) mechanism, is critical for cell proliferation and survival. Extensive telomere shortening or loss of telomere integrity activates DNA damage checkpoints, leading to cell senescence or death. Although telomerase upregulation is an attractive target for anti-cancer therapy, the lag associated with telomere shortening and the potential activation of ALT pose a challenge. An alternative approach is to modify telomere interactions with binding proteins (telomere uncapping). G-quadruplex ligands stabilize structures generated from single-stranded G-rich 3'-telomere end (G-quadruplex) folding, which in principle, cannot be elongated by telomerase, thus leading to telomere shortening. Ligands can also mediate rapid anti-proliferative effects by telomere uncapping. We previously reported that the G-quadruplex ligand, phenylphenanthroimidazole ethylenediamine platinum(II) (PIP), inhibits telomerase activity in vitro[47]. In the current study, a long-term seeding assay showed that PIP significantly inhibited the seeding capacity of A549 lung cancer cells and to a lesser extent primary MRC5 fibroblast cells. Importantly, treatment with PIP caused a significant dose- and time-dependent decrease in average telomere length of A549 but not MRC5 cells. Moreover, cell cycle analysis revealed a significant increase in G1 arrest upon treatment of A549 cells, but not MRC5 cells. Both apoptosis and cellular senescence may contribute to the anti-proliferative effects of PIP. Our studies validate the development of novel and specific therapeutic ligands targeting telomeric G-quadruplex structures in cancer cells.
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Kemp JR, Longworth MS. Crossing the LINE Toward Genomic Instability: LINE-1 Retrotransposition in Cancer. Front Chem 2015; 3:68. [PMID: 26734601 PMCID: PMC4679865 DOI: 10.3389/fchem.2015.00068] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/27/2015] [Indexed: 12/17/2022] Open
Abstract
Retrotransposons are repetitive DNA sequences that are positioned throughout the human genome. Retrotransposons are capable of copying themselves and mobilizing new copies to novel genomic locations in a process called retrotransposition. While most retrotransposon sequences in the human genome are incomplete and incapable of mobilization, the LINE-1 retrotransposon, which comprises~17% of the human genome, remains active. The disruption of cellular mechanisms that suppress retrotransposon activity is linked to the generation of aneuploidy, a potential driver of tumor development. When retrotransposons insert into a novel genomic region, they have the potential to disrupt the coding sequence of endogenous genes and alter gene expression, which can lead to deleterious consequences for the organism. Additionally, increased LINE-1 copy numbers provide more chances for recombination events to occur between retrotransposons, which can lead to chromosomal breaks and rearrangements. LINE-1 activity is increased in various cancer cell lines and in patient tissues resected from primary tumors. LINE-1 activity also correlates with increased cancer metastasis. This review aims to give a brief overview of the connections between LINE-1 retrotransposition and the loss of genome stability. We will also discuss the mechanisms that repress retrotransposition in human cells and their links to cancer.
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Affiliation(s)
- Jacqueline R Kemp
- Department of Cellular and Molecular Medicine, Lerner Research Institute of Cleveland Clinic Cleveland, OH, USA
| | - Michelle S Longworth
- Department of Cellular and Molecular Medicine, Lerner Research Institute of Cleveland Clinic Cleveland, OH, USA
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Bersani F, Lee E, Kharchenko PV, Xu AW, Liu M, Xega K, MacKenzie OC, Brannigan BW, Wittner BS, Jung H, Ramaswamy S, Park PJ, Maheswaran S, Ting DT, Haber DA. Pericentromeric satellite repeat expansions through RNA-derived DNA intermediates in cancer. Proc Natl Acad Sci U S A 2015; 112:15148-53. [PMID: 26575630 PMCID: PMC4679016 DOI: 10.1073/pnas.1518008112] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Aberrant transcription of the pericentromeric human satellite II (HSATII) repeat is present in a wide variety of epithelial cancers. In deriving experimental systems to study its deregulation, we observed that HSATII expression is induced in colon cancer cells cultured as xenografts or under nonadherent conditions in vitro, but it is rapidly lost in standard 2D cultures. Unexpectedly, physiological induction of endogenous HSATII RNA, as well as introduction of synthetic HSATII transcripts, generated cDNA intermediates in the form of DNA/RNA hybrids. Single molecule sequencing of tumor xenografts showed that HSATII RNA-derived DNA (rdDNA) molecules are stably incorporated within pericentromeric loci. Suppression of RT activity using small molecule inhibitors reduced HSATII copy gain. Analysis of whole-genome sequencing data revealed that HSATII copy number gain is a common feature in primary human colon tumors and is associated with a lower overall survival. Together, our observations suggest that cancer-associated derepression of specific repetitive sequences can promote their RNA-driven genomic expansion, with potential implications on pericentromeric architecture.
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Affiliation(s)
- Francesca Bersani
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129
| | - Eunjung Lee
- Center for Biomedical Informatics, Harvard Medical School, Boston, MA 02115; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115
| | - Peter V Kharchenko
- Center for Biomedical Informatics, Harvard Medical School, Boston, MA 02115; Hematology/Oncology Program, Children's Hospital, Boston, MA 02115
| | - Andrew W Xu
- Center for Biomedical Informatics, Harvard Medical School, Boston, MA 02115
| | - Mingzhu Liu
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129; Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - Kristina Xega
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129
| | - Olivia C MacKenzie
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129
| | - Brian W Brannigan
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129
| | - Ben S Wittner
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129
| | | | - Sridhar Ramaswamy
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129; Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
| | - Peter J Park
- Center for Biomedical Informatics, Harvard Medical School, Boston, MA 02115; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115; Informatics Program, Children's Hospital, Boston, MA 02115
| | - Shyamala Maheswaran
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129; Department of Surgery, Massachusetts General Hospital, Boston, MA 02114
| | - David T Ting
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129; Department of Medicine, Massachusetts General Hospital, Boston, MA 02114;
| | - Daniel A Haber
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129; Howard Hughes Medical Institute, Chevy Chase, MD 20815; Department of Medicine, Massachusetts General Hospital, Boston, MA 02114;
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225
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Shirgahi Talari F, Bagherzadeh K, Golestanian S, Jarstfer M, Amanlou M. Potent Human Telomerase Inhibitors: Molecular Dynamic Simulations, Multiple Pharmacophore-Based Virtual Screening, and Biochemical Assays. J Chem Inf Model 2015; 55:2596-610. [PMID: 26529120 DOI: 10.1021/acs.jcim.5b00336] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Telomere maintenance is a universal cancer hallmark, and small molecules that disrupt telomere maintenance generally have anticancer properties. Since the vast majority of cancer cells utilize telomerase activity for telomere maintenance, the enzyme has been considered as an anticancer drug target. Recently, rational design of telomerase inhibitors was made possible by the determination of high resolution structures of the catalytic telomerase subunit from a beetle and subsequent molecular modeling of the human telomerase complex. A hybrid strategy including docking, pharmacophore-based virtual screening, and molecular dynamics simulations (MDS) were used to identify new human telomerase inhibitors. Docking methodology was applied to investigate the ssDNA telomeric sequence and two well-known human telomerase inhibitors' (BIBR1532 and MST-312) modes of interactions with hTERT TEN domain. Subsequently molecular dynamic simulations were performed to monitor and compare hTERT TEN domain, TEN-ssDNA, TEN-BIBR1532, TEN-MST-312, and TEN-ssDNA-BIBR1532 behavior in a dynamic environment. Pharmacophore models were generated considering the inhibitors manner in the TEN domain anchor site. These exploratory studies identified several new potent inhibitors whose IC50 values were generated experimentally in a low micromolar range with the aid of biochemical assays, including both the direct telomerase and the telomeric repeat amplification protocol (TRAP) assays. The results suggest that the current models of human telomerase are useful templates for rational inhibitor design.
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Affiliation(s)
- Faezeh Shirgahi Talari
- Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences , Tehran, 14155-6451, Iran.,Eshelman School of Pharmacy, Division of Chemical Biology and Medicinal Chemistry, University of North Carolina , Chapel Hill, North Carolina 27599, United States
| | - Kowsar Bagherzadeh
- Razi Drug Research Center, Iran University of Medical Sciences , Tehran, 1449614535, Iran
| | - Sahand Golestanian
- Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences , Tehran, 14155-6451, Iran
| | - Michael Jarstfer
- Eshelman School of Pharmacy, Division of Chemical Biology and Medicinal Chemistry, University of North Carolina , Chapel Hill, North Carolina 27599, United States
| | - Massoud Amanlou
- Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences , Tehran, 14155-6451, Iran
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226
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Dokládal L, Honys D, Rana R, Lee LY, Gelvin SB, Sýkorová E. cDNA Library Screening Identifies Protein Interactors Potentially Involved in Non-Telomeric Roles of Arabidopsis Telomerase. FRONTIERS IN PLANT SCIENCE 2015; 6:985. [PMID: 26617625 PMCID: PMC4641898 DOI: 10.3389/fpls.2015.00985] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/27/2015] [Indexed: 05/27/2023]
Abstract
Telomerase-reverse transcriptase (TERT) plays an essential catalytic role in maintaining telomeres. However, in animal systems telomerase plays additional non-telomeric functional roles. We previously screened an Arabidopsis cDNA library for proteins that interact with the C-terminal extension (CTE) TERT domain and identified a nuclear-localized protein that contains an RNA recognition motif (RRM). This RRM-protein forms homodimers in both plants and yeast. Mutation of the gene encoding the RRM-protein had no detectable effect on plant growth and development, nor did it affect telomerase activity or telomere length in vivo, suggesting a non-telomeric role for TERT/RRM-protein complexes. The gene encoding the RRM-protein is highly expressed in leaf and reproductive tissues. We further screened an Arabidopsis cDNA library for proteins that interact with the RRM-protein and identified five interactors. These proteins are involved in numerous non-telomere-associated cellular activities. In plants, the RRM-protein, both alone and in a complex with its interactors, localizes to nuclear speckles. Transcriptional analyses in wild-type and rrm mutant plants, as well as transcriptional co-analyses, suggest that TERT, the RRM-protein, and the RRM-protein interactors may play important roles in non-telomeric cellular functions.
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Affiliation(s)
- Ladislav Dokládal
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology and Faculty of Science, Masaryk UniversityBrno, Czech Republic
- Institute of Biophysics – Academy of Sciences of the Czech Republic v.v.i.Brno, Czech Republic
| | - David Honys
- Institute of Experimental Botany – Academy of Sciences of the Czech Republic v.v.i.Prague, Czech Republic
| | - Rajiv Rana
- Institute of Experimental Botany – Academy of Sciences of the Czech Republic v.v.i.Prague, Czech Republic
| | - Lan-Ying Lee
- Department of Biological Sciences, Purdue University, West LafayetteIN, USA
| | - Stanton B. Gelvin
- Department of Biological Sciences, Purdue University, West LafayetteIN, USA
| | - Eva Sýkorová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology and Faculty of Science, Masaryk UniversityBrno, Czech Republic
- Institute of Biophysics – Academy of Sciences of the Czech Republic v.v.i.Brno, Czech Republic
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227
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Fernández Larrosa PN, Ruíz Grecco M, Mengual Gómez D, Alvarado CV, Panelo LC, Rubio MF, Alonso DF, Gómez DE, Costas MA. RAC3 more than a nuclear receptor coactivator: a key inhibitor of senescence that is downregulated in aging. Cell Death Dis 2015; 6:e1902. [PMID: 26469953 PMCID: PMC4632280 DOI: 10.1038/cddis.2015.218] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 06/24/2015] [Accepted: 07/01/2015] [Indexed: 11/10/2022]
Abstract
Receptor-associated coactivator 3 (RAC3) is a nuclear receptor coactivator usually overexpressed in tumors that exerts oncogenic functions in the cytoplasm and the nucleus. Although as part of its oncogenic actions it was previously identified as an inhibitor of apoptosis and autophagy, its expression is required in order to preserve the pluripotency and embryonic stem cell self-renewal. In this work we investigated its role in cellular senescence. We found that RAC3 overexpression in the nontumoral HEK293 cells inhibits the premature senescence induced by hydrogen peroxide or rapamycin. The mechanism involves not only the inhibition of autophagy early induced by these stimuli in the pathway to senescence, but also the increase in levels and nuclear localization of both the cell cycle suppressors p53/p21 and the longevity promoters FOXO1A, FOXO3A and SIRT1. Furthermore, we found that RAC3 overexpression is required in order to maintain the telomerase activity. In tumoral HeLa cells its activity was inhibited by depletion of RAC3 inducing replicative senescence. Moreover, we demonstrated that in vivo, levels of RAC3 are downregulated in the liver from aged as compared with young rats, whereas the levels of p21 are increased, correlating with the expected senescent cell contents in aged tissues. A similar downregulation of RAC3 was observed in the premature and replicative senescence of human fetal WI-38 cells and premature senescence of hepatocyte HepG2 cell line. Taken together, all these results demonstrate that RAC3 is an inhibitor of senescence whose downregulation in aged individuals could be probably a tumor suppressor mechanism, avoiding the clonal expansion of risky old cells having damaged DNA.
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Affiliation(s)
- P N Fernández Larrosa
- Laboratorio de Biología Molecular y Apoptosis, Instituto de Investigaciones Médicas Alfredo Lanari, IDIM-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Combatientes de Malvinas 3150, Buenos Aires C1427ARO, Argentina
| | - M Ruíz Grecco
- Laboratorio de Biología Molecular y Apoptosis, Instituto de Investigaciones Médicas Alfredo Lanari, IDIM-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Combatientes de Malvinas 3150, Buenos Aires C1427ARO, Argentina
| | - D Mengual Gómez
- Laboratorio de Oncología Molecular, Universidad Nacional de Quilmes, R. Sáenz Peña 352, Bernal, Buenos Aires B1876BXD Argentina
| | - C V Alvarado
- Laboratorio de Biología Molecular y Apoptosis, Instituto de Investigaciones Médicas Alfredo Lanari, IDIM-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Combatientes de Malvinas 3150, Buenos Aires C1427ARO, Argentina
| | - L C Panelo
- Laboratorio de Biología Molecular y Apoptosis, Instituto de Investigaciones Médicas Alfredo Lanari, IDIM-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Combatientes de Malvinas 3150, Buenos Aires C1427ARO, Argentina
| | - M F Rubio
- Laboratorio de Biología Molecular y Apoptosis, Instituto de Investigaciones Médicas Alfredo Lanari, IDIM-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Combatientes de Malvinas 3150, Buenos Aires C1427ARO, Argentina
| | - D F Alonso
- Laboratorio de Oncología Molecular, Universidad Nacional de Quilmes, R. Sáenz Peña 352, Bernal, Buenos Aires B1876BXD Argentina
| | - D E Gómez
- Laboratorio de Oncología Molecular, Universidad Nacional de Quilmes, R. Sáenz Peña 352, Bernal, Buenos Aires B1876BXD Argentina
| | - M A Costas
- Laboratorio de Biología Molecular y Apoptosis, Instituto de Investigaciones Médicas Alfredo Lanari, IDIM-CONICET, Facultad de Medicina, Universidad de Buenos Aires, Combatientes de Malvinas 3150, Buenos Aires C1427ARO, Argentina
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228
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Li T, Leng XS, Zhu JY, Wang FS. Establishment and characterization of an immortalized rat hepatic stellate cell line. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:12064-12074. [PMID: 26722391 PMCID: PMC4680336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 09/23/2015] [Indexed: 06/05/2023]
Abstract
Hepatic stellate cells (HSCs) play an important role in liver fibrosis and portal hypertension. This study established a new rat HSC cell line LSC-1. Liver ex vivo perfusion with collagenase IV and density gradient centrifugation were used to isolate rat HSC. Cells have been maintained in culture for multiple passages. LSC-1 cell biological characteristics were studied. LSC-1 cell have been maintained in culture over 100 passages. This new HSC cell line express telomerase reverse transcriptase (TRT) and p53, suggesting that it is immortalized spontaneously. LSC-1 cells have a doubling time of 46 hours and their growth is serum-dependent. Karyotypic analysis revealed that LSC-1 cells possess normal chromosome phenotype. Moreover, LSC-1 cells do not grow in soft agar or induce tumors in nude mice, suggesting that they are not transformed. LSC-1 cells express desmin, glial fibrillary acidic proteins (GFAP), collagen type I and III, α-smooth muscle actin (α-SMA), transforming growth factor β1 (TGF-β1), platelet derived growth factor B (PDGF-B) and inducible nitric oxide synthase (iNOS). TGF-β1 stimulation increased collagen type I and III expression in LSC-1 cells. Additionally, LSC-1 cells proliferate in response to PDGF-BB, and contract in response to endothelin-1 (ET-1). In summary, LSC-1 cells exhibit activated HSC phenotype characteristics, and therefore are useful tool to study the pathogenesis of liver cirrhosis and portal hypertension.
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Affiliation(s)
- Tao Li
- Department of Hepatobiliary Surgery, Peking University People's Hospital Beijing, P. R. China
| | - Xi-Sheng Leng
- Department of Hepatobiliary Surgery, Peking University People's Hospital Beijing, P. R. China
| | - Ji-Ye Zhu
- Department of Hepatobiliary Surgery, Peking University People's Hospital Beijing, P. R. China
| | - Fu-Shun Wang
- Department of Hepatobiliary Surgery, Peking University People's Hospital Beijing, P. R. China
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229
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Repression of hTERT transcription by the introduction of chromosome 3 into human oral squamous cell carcinoma. Biochem Biophys Res Commun 2015; 466:755-9. [PMID: 26410534 DOI: 10.1016/j.bbrc.2015.09.119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 09/22/2015] [Indexed: 12/13/2022]
Abstract
Telomerase is a ribonucleoprotein enzyme that maintains telomere length. Telomerase activity is primarily attributed to the expression of telomerase reverse transcriptase (TERT). It has been reported that introduction of an intact human chromosome 3 into the human oral squamous cell carcinoma cell line HSC3 suppresses the tumorigenicity of these cells. However, the mechanisms that regulate tumorigenicity have not been elucidated. To determine whether this reduction in tumorigenicity was accompanied by a reduction in telomerase activity, we investigated the transcriptional activation of TERT in HSC3 microcell hybrid clones with an introduced human chromosome 3 (HSC3#3). HSC#3 cells showed inhibition of hTERT transcription compared to that of the parental HSC3 cells. Furthermore, cell fusion experiments showed that hybrids of HSC3 cells and cells of the RCC23 renal carcinoma cell line, which also exhibits suppression of TERT transcription by the introduction of human chromosome 3, also displayed suppressed TERT transcription. These results suggested that human chromosome 3 may carry functionally distinct, additional TERT repressor genes.
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230
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Laish I, Katz H, Stein A, Liberman M, Naftali T, Kitay-Cohen Y, Biron-Shental T, Konikoff FM, Amiel A. Telomere dysfunction in peripheral blood lymphocytes from patients with primary sclerosing cholangitis and inflammatory bowel disease. Dig Liver Dis 2015; 47:790-6. [PMID: 26048252 DOI: 10.1016/j.dld.2015.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 04/18/2015] [Accepted: 05/04/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND AIMS Primary sclerosing cholangitis and inflammatory bowel disease are two associated, chronic inflammatory, pre-malignant conditions. We hypothesized that patients with these disorders may harbour telomere dysfunction as a marker of chromosomal instability. The aim of our study was to compare parameters of the telomere-telomerase system in these cohorts. METHODS In this prospective study, peripheral blood was withdrawn from patients with primary sclerosing cholangitis (N=20), inflammatory bowel disease (N=20) and healthy controls (N=20), and lymphocytes were isolated. Telomere length was quantified as a function of the signal intensity and telomere number. Random aneuploidy and telomere capture were determined by fluorescence in situ hybridization technique with specific probes. RESULTS Patients with inflammatory bowel disease had higher measures of intestinal disease activity than patients with primary sclerosing cholangitis. Despite this, shorter telomere length and telomere aggregates, especially the fusion of 2-5 telomeres, were observed at significantly higher rate in patients with primary sclerosing cholangitis relative to inflammatory bowel disease or healthy controls. Rates of aneuploidy and telomere capture were higher in the two probes in both diseases compared to controls (p<0.001). CONCLUSION Dysfunction of telomeres was demonstrated in primary sclerosing cholangitis patients more than inflammatory bowel disease and healthy controls patients, which attests to genetic instability and immunosenescence. TRIAL REGISTRATION NUMBER NCT02247622.
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Affiliation(s)
- Ido Laish
- Gastroenterology and Hepatology Institute, Meir Medical Center, Kfar Saba, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Hila Katz
- Genetic Institute, Meir Medical Center, Kfar Saba, Israel; Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel
| | - Assaf Stein
- Gastroenterology and Hepatology Institute, Meir Medical Center, Kfar Saba, Israel
| | - Meytal Liberman
- Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel
| | - Timna Naftali
- Gastroenterology and Hepatology Institute, Meir Medical Center, Kfar Saba, Israel
| | - Yona Kitay-Cohen
- Gastroenterology and Hepatology Institute, Meir Medical Center, Kfar Saba, Israel
| | - Tal Biron-Shental
- Department of Obstetrics and Gynecology, Meir Medical Center, Kfar Saba, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Fred M Konikoff
- Gastroenterology and Hepatology Institute, Meir Medical Center, Kfar Saba, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Aliza Amiel
- Genetic Institute, Meir Medical Center, Kfar Saba, Israel; Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel
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Zhang X, Cheng R, Shi Z, Jin Y. A PCR-free fluorescence strategy for detecting telomerase activity via double amplification strategy. Biosens Bioelectron 2015; 75:101-7. [PMID: 26299822 DOI: 10.1016/j.bios.2015.08.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 08/04/2015] [Accepted: 08/08/2015] [Indexed: 01/23/2023]
Abstract
As a universal tumor biomarker, research on the activity and inhibition of telomerase is of great importance for cancer diagnosis and therapy. Although the telomeric repeat amplification protocol (TRAP) has served as a powerful assay for detecting telomerase activity, its application has been significantly limited by amplification related errors and time-consuming procedure. To address the limitations of PCR-based protocol, a dual amplification fluorescence assay was developed for PCR-free detecting telomerase activity. Briefly, we designed an arch-structure DNA probe to specifically control strand displacement reaction and subsequent enzyme-aided amplification. Telomerase substrate (TS) primer was extended by telomerase to form long elongation products which contain several TTAGGG repeat units. So, one elongation product can release more than one trigger DNA (t-DNA) via strand displacement reaction to realize first amplification. Subsequently, t-DNA specifically opened molecular beacon (MB) to restore the fluorescence of MB. Meanwhile, t-DNA was recycled by the aid of nicking endonuclease to continuously open more and more MBs, leading to a second amplification. Owing to the double amplification strategy, the proposed method allowed the measurement of telomerase activity in crude cell extracts equivalent to 5 HeLa cells and 10 CCRF-CEM cells without PCR amplification. Besides, the influence of telomere-binding ligands on the telomerase activity demonstrated that the proposed method holds the potential to evaluate the inhibition efficiency of telomerase inhibitors.
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Affiliation(s)
- Xiafei Zhang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China
| | - Rui Cheng
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China
| | - Zhilu Shi
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China
| | - Yan Jin
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China.
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Udomsinprasert W, Poovorawan Y, Chongsrisawat V, Vejchapipat P, Zhan D, Honsawek S. Telomere Length in Peripheral Blood Leukocytes Is Associated with Severity of Biliary Atresia. PLoS One 2015; 10:e0134689. [PMID: 26230851 PMCID: PMC4521951 DOI: 10.1371/journal.pone.0134689] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 07/13/2015] [Indexed: 01/29/2023] Open
Abstract
Objective The purpose of this study was to investigate the association of telomere length in peripheral blood leukocytes with the severity of biliary atresia (BA). Methods One hundred and fourteen BA patients and 114 age-matched healthy controls were enrolled. Relative telomere length (RTL) was assessed using a quantitative real-time polymerase chain reaction. Multivariate regression analysis was used to estimate RTL as an independent risk factor of BA. Receiver operating characteristic curve analysis was used to calculate the accuracy of biomarkers in the prediction of liver cirrhosis. Results BA patients had significantly shorter telomeres than healthy controls (p < 0.0001). The RTL in BA patients with jaundice was considerably lower than that of patients without jaundice (p = 0.005). Moreover, RTL was markedly shorter in patients with cirrhosis (F4), as compared to patients with mild fibrosis (F2) and non-fibrosis (F0-F1, p < 0.0001). Logistic regression analysis indicated that short RTL was associated with a higher risk of liver cirrhosis in BA. Tertile analysis showed a dose-response effect for this association (p trend < 0.0001). Additionally, RTL in BA children revealed a negative correlation with age (r = -0.50, p < 0.001). We noted an association between reduction of RTL and liver stiffness scores, adjusted for age and gender (b = -0.01, p < 0.0001). Short RTL can be employed to distinguish cirrhosis patients from non-cirrhosis patients (AUC = 0.78). Further analysis showed a linear correlation between leukocyte RTL and liver RTL in BA patients (r = 0.83, p < 0.001). Conclusion The findings of this study provide evidence that telomere shortening is associated with an elevated risk of liver cirrhosis in BA.
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Affiliation(s)
- Wanvisa Udomsinprasert
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand
| | - Yong Poovorawan
- Center of Excellence in Clinical Virology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand
| | - Voranush Chongsrisawat
- Center of Excellence in Clinical Virology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand
| | - Paisarn Vejchapipat
- Department of Surgery, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand
| | - Dong Zhan
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand
| | - Sittisak Honsawek
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand
- * E-mail:
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233
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Chiba K, Johnson JZ, Vogan JM, Wagner T, Boyle JM, Hockemeyer D. Cancer-associated TERT promoter mutations abrogate telomerase silencing. eLife 2015. [PMID: 26194807 PMCID: PMC4507476 DOI: 10.7554/elife.07918] [Citation(s) in RCA: 196] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mutations in the human telomerase reverse transcriptase (TERT) promoter are the most frequent non-coding mutations in cancer, but their molecular mechanism in tumorigenesis has not been established. We used genome editing of human pluripotent stem cells with physiological telomerase expression to elucidate the mechanism by which these mutations contribute to human disease. Surprisingly, telomerase-expressing embryonic stem cells engineered to carry any of the three most frequent TERT promoter mutations showed only a modest increase in TERT transcription with no impact on telomerase activity. However, upon differentiation into somatic cells, which normally silence telomerase, cells with TERT promoter mutations failed to silence TERT expression, resulting in increased telomerase activity and aberrantly long telomeres. Thus, TERT promoter mutations are sufficient to overcome the proliferative barrier imposed by telomere shortening without additional tumor-selected mutations. These data establish that TERT promoter mutations can promote immortalization and tumorigenesis of incipient cancer cells. DOI:http://dx.doi.org/10.7554/eLife.07918.001 The bulk of the DNA in the human genome is divided between 23 pairs of chromosomes. The ends of these chromosomes contain a repetitive stretch of DNA known as a telomere. Every time a cell divides, a portion of the telomere is lost and can be restored by an enzyme called telomerase. If the telomeres shorten below a critical length, the cell can no longer divide and eventually dies. Thus, long telomeres increase the number of times a cell can divide. In the majority of human cells—with the exception of stem cells—telomerase activity is absent due to the down regulation of the active protein component (called TERT) after birth. Therefore, the telomeres in these cells shorten after each cell division. However, 90% of human cancers have very high TERT activity, which enables them to divide continuously to drive tumor growth. Genes are sections of DNA that code for proteins and other molecules. The start of a gene contains a region known as the promoter, which controls when and where in the body the gene is active. Cancer cells often contain mutations in the promoter of the gene that encodes TERT. However, it remains poorly understood how these mutations lead to the formation of tumors. Chiba et al. have now used a technique called genome editing to introduce mutations that are commonly found in cancer cells into the promoter of the gene for TERT in human embryonic stem cells. Unexpectedly, these changes did not increase the activity of the telomerase enzyme in these cells, nor did they increase the length of the telomeres. Chiba et al. next caused these genetically engineered stem cells to develop into more specialized cell types—such as nerve cells. These ‘differentiated’ cells normally silence the gene that encodes TERT, but the mutations prevented the gene from being silenced. This led to abnormally high levels of telomerase activity and long telomeres. The experiments also showed that TERT activity in these cells was similar to that found in cancer cells that can divide indefinitely. Cells containing the promoter mutations were then injected into mice. The cells formed a mass of tumors that contained very long telomeres. These results together suggest that cancer-causing mutations in the gene for TERT stop this gene from being properly silenced in more specialized cells, and that this, on its own, can promote the formation of tumors. These findings are likely to underpin future efforts to treat cancers by targeting the expression and activity of the telomerase enzyme. DOI:http://dx.doi.org/10.7554/eLife.07918.002
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Affiliation(s)
- Kunitoshi Chiba
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Joshua Z Johnson
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Jacob M Vogan
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Tina Wagner
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - John M Boyle
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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234
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ZHAO QIANG, WANG XUEYAO, YU XIAOXIA, ZHAI YINGXIAN, HE XU, WU SHAN, SHI YINGAI. Expression of human telomerase reverse transcriptase mediates the senescence of mesenchymal stem cells through the PI3K/AKT signaling pathway. Int J Mol Med 2015; 36:857-64. [DOI: 10.3892/ijmm.2015.2284] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 07/08/2015] [Indexed: 11/06/2022] Open
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235
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Impaired telomerase activity hinders proliferation and in vitro transformation of Penaeus monodon lymphoid cells. Cytotechnology 2015; 68:1301-14. [PMID: 26084784 DOI: 10.1007/s10616-015-9890-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 05/19/2015] [Indexed: 12/16/2022] Open
Abstract
Retaining terminal transferase activity of telomerase, the ribonucleoprotein enzyme which add telomeric repeats on chromosome end is thought to be required to prevent cellular ageing. Additionally, telomerase considered as a marker for cell proliferation and immortalization in eukaryotes. We examined telomerase activity in tissues and lymphoid cell culture of Penaeus monodon. Along with telomerase activity, telomere repeats and an attempt on identification of telomerase reverse transcriptase (PmTERT) were made. Telomeric repeat amplification protocol revealed that telomerase-dependent telomeric lengthening has been taking place in P. monodon and the adult tissues were retaining this capacity throughout their lifespan with the highest activity in ovary, testis and lymphoid organ. However, telomerase activity could not be detected in lymphoid cells in culture. The canonical telomeric repeats added by telomerase of lymphoid tissue extract were identified as TTAGG, but pentameric repeats GGTTA and AGGTT were also added by the telomerase. PmTERT protein sequence (partial) shared 100 % identity with the TERT sequence of Daphnia pulex, 27 % sequence identity with Purple sea urchin and 24-25 % with Zebra fish. Undetectable telomerase activity in lymphoid cell culture supports the hypothesis that the inadequate telomerase activity or gene expression may be a reason that prevents neoplastic transformation and spontaneous immortalization of the cells in vitro. Thus, it is envisaged that telomerase activation in lymphoid cells may surmount cellular ageing for in vitro transformation and cell line establishment.
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236
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Fatima R, Akhade VS, Pal D, Rao SMR. Long noncoding RNAs in development and cancer: potential biomarkers and therapeutic targets. MOLECULAR AND CELLULAR THERAPIES 2015; 3:5. [PMID: 26082843 PMCID: PMC4469312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 05/19/2015] [Indexed: 11/21/2023]
Abstract
Long noncoding RNAs are emerging as key players in various fundamental biological processes. We highlight the varied molecular mechanisms by which lncRNAs modulate gene expression in diverse cellular contexts and their role in early mammalian development in this review. Furthermore, it is being increasingly recognized that altered expression of lncRNAs is specifically associated with tumorigenesis, tumor progression and metastasis. We discuss various lncRNAs implicated in different cancer types with a focus on their clinical applications as potential biomarkers and therapeutic targets in the pathology of diverse cancers.
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Affiliation(s)
- Roshan Fatima
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur, Bangalore 560064 India
| | - Vijay Suresh Akhade
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur, Bangalore 560064 India
| | - Debosree Pal
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur, Bangalore 560064 India
| | - Satyanarayana MR Rao
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur, Bangalore 560064 India
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237
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Fatima R, Akhade VS, Pal D, Rao SM. Long noncoding RNAs in development and cancer: potential biomarkers and therapeutic targets. MOLECULAR AND CELLULAR THERAPIES 2015; 3:5. [PMID: 26082843 PMCID: PMC4469312 DOI: 10.1186/s40591-015-0042-6] [Citation(s) in RCA: 203] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 05/19/2015] [Indexed: 02/07/2023]
Abstract
Long noncoding RNAs are emerging as key players in various fundamental biological processes. We highlight the varied molecular mechanisms by which lncRNAs modulate gene expression in diverse cellular contexts and their role in early mammalian development in this review. Furthermore, it is being increasingly recognized that altered expression of lncRNAs is specifically associated with tumorigenesis, tumor progression and metastasis. We discuss various lncRNAs implicated in different cancer types with a focus on their clinical applications as potential biomarkers and therapeutic targets in the pathology of diverse cancers.
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Affiliation(s)
- Roshan Fatima
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur, Bangalore 560064 India
| | - Vijay Suresh Akhade
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur, Bangalore 560064 India
| | - Debosree Pal
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur, Bangalore 560064 India
| | - Satyanarayana Mr Rao
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur, Bangalore 560064 India
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238
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Lin X, Peng Z, Su C. Potential anti-cancer activities and mechanisms of costunolide and dehydrocostuslactone. Int J Mol Sci 2015; 16:10888-906. [PMID: 25984608 PMCID: PMC4463681 DOI: 10.3390/ijms160510888] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 04/10/2015] [Accepted: 04/22/2015] [Indexed: 12/31/2022] Open
Abstract
Costunolide (CE) and dehydrocostuslactone (DE) are derived from many species of medicinal plants, such as Saussurea lappa Decne and Laurus nobilis L. They have been reported for their wide spectrum of biological effects, including anti-inflammatory, anticancer, antiviral, antimicrobial, antifungal, antioxidant, antidiabetic, antiulcer, and anthelmintic activities. In recent years, they have caused extensive interest in researchers due to their potential anti-cancer activities for various types of cancer, and their anti-cancer mechanisms, including causing cell cycle arrest, inducing apoptosis and differentiation, promoting the aggregation of microtubule protein, inhibiting the activity of telomerase, inhibiting metastasis and invasion, reversing multidrug resistance, restraining angiogenesis has been studied. This review will summarize anti-cancer activities and associated molecular mechanisms of these two compounds for the purpose of promoting their research and application.
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Affiliation(s)
- Xuejing Lin
- Department of Molecular Oncology, Eastern Hepatobiliary Surgical Hospital & National Center of Liver Cancer, Second Military Medical University, Shanghai 200438, China.
| | - Zhangxiao Peng
- Department of Molecular Oncology, Eastern Hepatobiliary Surgical Hospital & National Center of Liver Cancer, Second Military Medical University, Shanghai 200438, China.
| | - Changqing Su
- Department of Molecular Oncology, Eastern Hepatobiliary Surgical Hospital & National Center of Liver Cancer, Second Military Medical University, Shanghai 200438, China.
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239
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Cho NW, Dilley RL, Lampson MA, Greenberg RA. Interchromosomal homology searches drive directional ALT telomere movement and synapsis. Cell 2015; 159:108-121. [PMID: 25259924 DOI: 10.1016/j.cell.2014.08.030] [Citation(s) in RCA: 266] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Revised: 06/16/2014] [Accepted: 08/25/2014] [Indexed: 12/17/2022]
Abstract
Telomere length maintenance is a requisite feature of cellular immortalization and a hallmark of human cancer. While most human cancers express telomerase activity, ∼10%-15% employ a recombination-dependent telomere maintenance pathway known as alternative lengthening of telomeres (ALT) that is characterized by multitelomere clusters and associated promyelocytic leukemia protein bodies. Here, we show that a DNA double-strand break (DSB) response at ALT telomeres triggers long-range movement and clustering between chromosome termini, resulting in homology-directed telomere synthesis. Damaged telomeres initiate increased random surveillance of nuclear space before displaying rapid directional movement and association with recipient telomeres over micron-range distances. This phenomenon required Rad51 and the Hop2-Mnd1 heterodimer, which are essential for homologous chromosome synapsis during meiosis. These findings implicate a specialized homology searching mechanism in ALT-dependent telomere maintenance and provide a molecular basis underlying the preference for recombination between nonsister telomeres during ALT.
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Affiliation(s)
- Nam Woo Cho
- Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA
| | - Robert L Dilley
- Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA
| | - Michael A Lampson
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Roger A Greenberg
- Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA; Department of Pathology, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA; Abramson Family Cancer Research Institute, Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA.
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240
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Hajdu SI, Vadmal M, Tang P. A note from history: Landmarks in history of cancer, part 7. Cancer 2015; 121:2480-513. [PMID: 25873516 DOI: 10.1002/cncr.29365] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 02/02/2015] [Indexed: 02/06/2023]
Abstract
In the 2 and half decades reviewed (1970-1995), research established that chromosomal translocation, deletion, and DNA amplification are prerequisites to cancerogenesis and that oncogenes, tumor-suppressor genes, growth factors, and cytokines play crucial roles in the pathomechanism of cancer. Human papillomavirus, human immunodeficiency virus, herpes virus, and hepatitis B virus were identified as cancer-causing viruses. Several laboratory tests were developed for the detection of primary and recurrent cancers, and cancer prevention by screening methods was popularized. Sonography, computerized tomography, magnetic resonance imaging, positron emission tomography, excision of sentinel lymph nodes, and immunohistochemical techniques became routine procedures. Clinicopathologic staging and classification of tumors were standardized. Limited surgery, adjuvant and neoadjuvant chemoradiation, and the therapeutic use of monoclonal antibodies, tumor vaccines, and targeted chemotherapy became routine practice. The decline in cancer incidence and mortality demonstrated that cancer prevention and advancement in oncology are pivotal to success in the crusade against cancer. Above all, it was clearly established that the care of patients with cancer can be accomplished best in a multidisciplinary setting involving surgical oncologists, radiologists, radiation therapists, medical oncologists, surgical pathologists, and laboratory scientists. In conclusion, the 25 years from 1970 and 1995 are the high-water mark in clinical oncology, and this is the period when oncology turned from art to science.
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Affiliation(s)
| | - Manjunath Vadmal
- Department of Dermatology, Los Angeles County-University of Southern California Medical Center, Los Angeles, California
| | - Ping Tang
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York
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241
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Yaswen P, MacKenzie KL, Keith WN, Hentosh P, Rodier F, Zhu J, Firestone GL, Matheu A, Carnero A, Bilsland A, Sundin T, Honoki K, Fujii H, Georgakilas AG, Amedei A, Amin A, Helferich B, Boosani CS, Guha G, Ciriolo MR, Chen S, Mohammed SI, Azmi AS, Bhakta D, Halicka D, Niccolai E, Aquilano K, Ashraf SS, Nowsheen S, Yang X. Therapeutic targeting of replicative immortality. Semin Cancer Biol 2015; 35 Suppl:S104-S128. [PMID: 25869441 PMCID: PMC4600408 DOI: 10.1016/j.semcancer.2015.03.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 03/06/2015] [Accepted: 03/13/2015] [Indexed: 12/15/2022]
Abstract
One of the hallmarks of malignant cell populations is the ability to undergo continuous proliferation. This property allows clonal lineages to acquire sequential aberrations that can fuel increasingly autonomous growth, invasiveness, and therapeutic resistance. Innate cellular mechanisms have evolved to regulate replicative potential as a hedge against malignant progression. When activated in the absence of normal terminal differentiation cues, these mechanisms can result in a state of persistent cytostasis. This state, termed “senescence,” can be triggered by intrinsic cellular processes such as telomere dysfunction and oncogene expression, and by exogenous factors such as DNA damaging agents or oxidative environments. Despite differences in upstream signaling, senescence often involves convergent interdependent activation of tumor suppressors p53 and p16/pRB, but can be induced, albeit with reduced sensitivity, when these suppressors are compromised. Doses of conventional genotoxic drugs required to achieve cancer cell senescence are often much lower than doses required to achieve outright cell death. Additional therapies, such as those targeting cyclin dependent kinases or components of the PI3K signaling pathway, may induce senescence specifically in cancer cells by circumventing defects in tumor suppressor pathways or exploiting cancer cells’ heightened requirements for telomerase. Such treatments sufficient to induce cancer cell senescence could provide increased patient survival with fewer and less severe side effects than conventional cytotoxic regimens. This positive aspect is countered by important caveats regarding senescence reversibility, genomic instability, and paracrine effects that may increase heterogeneity and adaptive resistance of surviving cancer cells. Nevertheless, agents that effectively disrupt replicative immortality will likely be valuable components of new combinatorial approaches to cancer therapy.
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Affiliation(s)
- Paul Yaswen
- Life Sciences Division, Lawrence Berkeley National Lab, Berkeley, CA, United States.
| | - Karen L MacKenzie
- Children's Cancer Institute Australia, Kensington, New South Wales, Australia.
| | | | | | | | - Jiyue Zhu
- Washington State University College of Pharmacy, Pullman, WA, United States.
| | | | | | - Amancio Carnero
- Instituto de Biomedicina de Sevilla, HUVR, Consejo Superior de Investigaciones Cientificas, Universdad de Sevilla, Seville, Spain.
| | | | | | | | | | | | | | - Amr Amin
- United Arab Emirates University, Al Ain, United Arab Emirates; Cairo University, Cairo, Egypt
| | - Bill Helferich
- University of Illinois at Urbana Champaign, Champaign, IL, United States
| | | | - Gunjan Guha
- SASTRA University, Thanjavur, Tamil Nadu, India
| | | | - Sophie Chen
- Ovarian and Prostate Cancer Research Trust, Guildford, Surrey, United Kingdom
| | | | - Asfar S Azmi
- Karmanos Cancer Institute, Wayne State University, Detroit, MI, United States
| | | | | | | | | | - S Salman Ashraf
- United Arab Emirates University, Al Ain, United Arab Emirates; Cairo University, Cairo, Egypt
| | | | - Xujuan Yang
- University of Illinois at Urbana Champaign, Champaign, IL, United States
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242
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Luo D, Mu Y. All-atomic simulations on human telomeric G-quadruplex DNA binding with thioflavin T. J Phys Chem B 2015; 119:4955-67. [PMID: 25806428 DOI: 10.1021/acs.jpcb.5b01107] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Ligand-stabilized human telomeric G-quadruplex DNA is believed to be an anticancer agent, as it can impede the continuous elongation of telomeres by telomerase in cancer cells. In this study, five well-established human telomeric G-quadruplex DNA models were probed on their binding behaviors with thioflavin T (ThT) via both conventional molecular dynamics (MD) and well-tempered metadynamics (WT-MetaD) simulations. Novel dynamics and characteristic binding patterns were disclosed by the MD simulations. It was observed that the K(+) promoted parallel and hybridized human telomeric G-quadruplex conformations pose higher binding affinities to ThT than the Na(+) and K(+) promoted basket conformations. It is the end, sandwich, and base stacking driven by π-π interactions that are identified as the major binding mechanisms. As the most energy favorable binding mode, the sandwich stacking observed in (3 + 1) hybridized form 1 G-quadruplex conformation is triggered by reversible conformational change of the G-quadruplex. To further examine the free energy landscapes, WT-MetaD simulations were utilized on G-quadruplex-ThT systems. It is found that all of the major binding modes predicted by the MD simulations are confirmed by the WT-MetaD simulations. The results in this work not only accord with existing experimental findings, but also reinforce our understanding on the dynamics of G-quadruplexes and aid future drug developments for G-quadruplex stabilization ligands.
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Affiliation(s)
- Di Luo
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Yuguang Mu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
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243
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Sunami Y, von Figura G, Kleger A, Strnad P, Hüser N, Hartmann D. The role of telomeres in liver disease. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 125:159-72. [PMID: 24993702 DOI: 10.1016/b978-0-12-397898-1.00007-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Telomeres stabilize open chromosome ends and protect them against chromosomal end-to-end fusions, breakage, instability, and nonreciprocal translocations. Telomere dysfunction is known to lead to an impaired regenerative capacity of hepatocytes and an increased cirrhosis formation in the context of acute and chronic liver injury. In addition, telomere dysfunction and telomerase mutations have been associated with the induction of chromosomal instability and consequently with cirrhosis development and hepatocarcinogenesis. The identification of molecular mechanisms related to telomere dysfunction and telomerase activation might lead to new therapeutic strategies. In this chapter, we are reviewing the current knowledge about the importance of telomere dysfunction in liver diseases.
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Affiliation(s)
- Yoshiaki Sunami
- Department of General Surgery, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Guido von Figura
- Department of Internal Medicine II, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Alexander Kleger
- Department of Internal Medicine I, Ulm University Hospital, Ulm, Germany
| | - Pavel Strnad
- Department of Internal Medicine III and IZKF, University Hospital Aachen, Aachen, Germany
| | - Norbert Hüser
- Department of General Surgery, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | - Daniel Hartmann
- Department of General Surgery, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
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244
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Biological potential of carbazole derivatives. Eur J Med Chem 2015; 94:405-26. [DOI: 10.1016/j.ejmech.2015.02.059] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 02/19/2015] [Accepted: 02/28/2015] [Indexed: 11/21/2022]
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245
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Armstrong RE, Riskowski RA, Strouse GF. Nanometal Surface Energy Transfer Optical Ruler for Measuring a Human Telomere Structure. Photochem Photobiol 2015; 91:732-8. [DOI: 10.1111/php.12423] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 01/01/2015] [Indexed: 12/23/2022]
Affiliation(s)
- Rachel E. Armstrong
- Department of Chemistry and Biochemistry; Florida State University; Tallahassee FL
| | - Ryan A. Riskowski
- Department of Chemistry and Biochemistry; Florida State University; Tallahassee FL
| | - Geoffrey F. Strouse
- Department of Chemistry and Biochemistry; Florida State University; Tallahassee FL
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246
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Aschacher T, Wolf B, Enzmann F, Kienzl P, Messner B, Sampl S, Svoboda M, Mechtcheriakova D, Holzmann K, Bergmann M. LINE-1 induces hTERT and ensures telomere maintenance in tumour cell lines. Oncogene 2015; 35:94-104. [PMID: 25798839 DOI: 10.1038/onc.2015.65] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 01/17/2015] [Accepted: 01/30/2015] [Indexed: 12/28/2022]
Abstract
A hallmark of cancer cells is an activated telomere maintenance mechanism, which allows prolonged survival of the malignant cells. In more than 80% of tumours, telomeres are elongated by the enzyme telomerase, which adds de novo telomere repeats to the ends of chromosomes. Cancer cells are also characterized by expression of active LINE-1 elements (L1s, long interspersed nuclear elements-1). L1 elements are abundant retrotransposons in the eukaryotic genome that are primarily known for facilitating aberrant recombination. Using L1-knockdown (KD), we show for the first time that L1 is critical for telomere maintenance in telomerase-positive tumour cells. The reduced length of telomeres in the L1-KD-treated cells correlated with an increased rate of telomere dysfunction foci, a reduced expression of shelterin proteins and an increased rate of anaphase bridges. The decreased telomere length was associated with a decreased telomerase activity and decreased telomerase mRNA level; the latter was increased upon L1 overexpression. L1-KD also led to a decrease in mRNA and protein expression of cMyc and KLF-4, two main transcription factors of telomerase and altered mRNA levels of other stem-cell-associated proteins such as CD44 and hMyb, as well as a corresponding reduced growth of spheroids. The KD of KLF-4 or cMyc decreased the level of L1-ORF1 mRNA, suggesting a specific reciprocal regulation with L1. Thus, our findings contribute to the understanding of L1 as a pathogenicity factor in cancer cells. As L1 is only expressed in pathophysiological conditions, L1 now appears to be target in the rational treatment of telomerase-positive cancer.
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Affiliation(s)
- T Aschacher
- Cardiac Surgical Research Laboratories, Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - B Wolf
- Surgery Research Laboratory, Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - F Enzmann
- Surgery Research Laboratory, Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - P Kienzl
- Surgery Research Laboratory, Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - B Messner
- Cardiac Surgical Research Laboratories, Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - S Sampl
- Department of Medicine I, Institute of Cancer Research, Vienna, Austria
| | - M Svoboda
- Department of Pathophysiology, Medical University of Vienna, Vienna, Austria
| | - D Mechtcheriakova
- Department of Pathophysiology, Medical University of Vienna, Vienna, Austria.,Comprehensive Cancer Center Vienna, Vienna, Austria
| | - K Holzmann
- Department of Medicine I, Institute of Cancer Research, Vienna, Austria.,Comprehensive Cancer Center Vienna, Vienna, Austria
| | - M Bergmann
- Surgery Research Laboratory, Department of Surgery, Medical University of Vienna, Vienna, Austria.,Comprehensive Cancer Center Vienna, Vienna, Austria
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247
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Akıncılar SC, Low KC, Liu CY, Yan TD, Oji A, Ikawa M, Li S, Tergaonkar V. Quantitative assessment of telomerase components in cancer cell lines. FEBS Lett 2015; 589:974-84. [PMID: 25749370 DOI: 10.1016/j.febslet.2015.02.035] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/06/2015] [Accepted: 02/26/2015] [Indexed: 12/22/2022]
Abstract
Besides its canonical function of catalyzing the formation of telomeric repeats, many groups have recently reported non-canonical functions of hTERT in particular, and telomerase in general. Regulating transcription is the central basis of non-canonical functions of telomerase. However, unlike reverse transcriptase activity of telomerase that requires only a few molecules of enzymatically active hTERT, non-canonical functions of hTERT or other telomerase components theoretically require several hundred copies. Here, we provide the first direct quantification of all the telomerase components in human cancer cell lines. We demonstrate that telomerase components do not exist in a 1:1 stoichiometric ratio, and there are several hundred copies of hTERT in cells. This provides the molecular basis of hTERT to function in other signaling cascades, including transcription.
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Affiliation(s)
- Semih Can Akıncılar
- Laboratory of NF-κB Signaling, Institute of Molecular and Cell Biology (IMCB), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore 117597, Singapore
| | - Kee Chung Low
- Laboratory of NF-κB Signaling, Institute of Molecular and Cell Biology (IMCB), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
| | - Chia Yi Liu
- Laboratory of NF-κB Signaling, Institute of Molecular and Cell Biology (IMCB), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
| | - Ting Dong Yan
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Asami Oji
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan; Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan; Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Shang Li
- Program in Cancer and Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Vinay Tergaonkar
- Laboratory of NF-κB Signaling, Institute of Molecular and Cell Biology (IMCB), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore 117597, Singapore.
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248
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The story of CD4+ CD28- T cells revisited: solved or still ongoing? J Immunol Res 2015; 2015:348746. [PMID: 25834833 PMCID: PMC4365319 DOI: 10.1155/2015/348746] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 02/10/2015] [Accepted: 02/19/2015] [Indexed: 02/07/2023] Open
Abstract
CD4+CD28− T cells are a unique type of proinflammatory T cells characterised by blockade of costimulatory CD28 receptor expression at the transcriptional level, which is still reversible by IL-12. In healthy individuals older than 65 years, these cells may accumulate to up to 50% of total CD4+ T lymphocytes as in many immune-mediated diseases, immunodeficiency, and specific infectious diseases. Here we focus on CD4+CD28− T cells in chronic immune-mediated diseases, summarizing various phenotypic and functional characteristics, which vary depending on the underlying disease, disease activity, and concurrent treatment. CD4+CD28− T cells present as effector/memory cells with increased replicative history and oligoclonality but reduced apoptosis. As an alternative costimulatory signal instead of CD28, not only natural killer cell receptors and Toll-like receptors, but also CD47, CTLA-4, OX40, and 4-1BB have to be considered. The proinflammatory and cytotoxic capacities of these cells indicate an involvement in progression and maintenance of chronic immune-mediated disease. So far it has been shown that treatment with TNF-α blockers, abatacept, statins, and polyclonal antilymphocyte globulins (ATG) mediates reduction of the CD4+CD28− T cell level. The clinical relevance of targeting CD4+CD28− T cells as a therapeutic option has not been examined so far.
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249
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Wang HY, Park S, Kim S, Lee D, Kim G, Kim Y, Park KH, Lee H. Use of hTERT and HPV E6/E7 mRNA RT-qPCR TaqMan assays in combination for diagnosing high-grade cervical lesions and malignant tumors. Am J Clin Pathol 2015; 143:344-51. [PMID: 25696792 DOI: 10.1309/ajcpf2xgz2xiqyqx] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
OBJECTIVES Human papillomavirus (HPV) is a major cause of cervical cancer, which is the second most common cancer in women. HPV E6 initiates degradation of cellular tumor suppressor protein p53, induces human telomerase reverse transcriptase (hTERT) activity, and then leads to progressive cervical carcinogenesis. METHODS In this study, the CervicGen HPV RT-qDX assay (Optipharm, Osong, Republic of Korea), which detects 16 HPV high-risk subtypes (HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68, and 69), and the CervicGen hTERT RT-qDX assay (Optipharm) were evaluated using 545 ThinPrep (Hologic, Bedford, MA) Papanicolaou samples. RESULTS The positivity for the HPV E6/E7 messenger RNA (mRNA) assay was 94.4%, 95.2%, 82.4%, 46.5%, 25.0%, and 1.1% in squamous cell carcinomas, high-grade squamous intraepithelial lesions (HSILs), atypical squamous cells--cannot exclude HSIL, low-grade squamous intraepithelial lesions, atypical squamous cells of undetermined significance, and normal cytology samples, respectively. Five cervical intraepithelial neoplasia grade 2+ samples were not detected by the HPV E6/E7 mRNA assay, but they exhibited positive signals in the hTERT mRNA assay. Notably, the hTERT mRNA expression level was increased in high-grade cervical lesions but was very low in all 288 normal samples. CONCLUSIONS These data suggest that the combination of HPV E6/E7 and hTERT mRNA expression levels could be used in a complementary manner in diagnosing high-grade cervical lesions and malignant tumors and might be useful as a predictive marker in monitoring low-grade cervical lesions.
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Affiliation(s)
- Hye-Young Wang
- M&D, Wonju Eco Environmental Technology Center, Wonju, Gangwon, Republic of Korea
| | - Sunyoung Park
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Gangwon, Republic of Korea
| | - Sunghyun Kim
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Gangwon, Republic of Korea
- Institute for Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Dongsup Lee
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Gangwon, Republic of Korea
- Department of Clinical Laboratory Science, Hyejeon College, Hongseong, Chungnam, Republic of Korea
| | - Geehyuk Kim
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Gangwon, Republic of Korea
| | - Yeun Kim
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Gangwon, Republic of Korea
| | - Kwang Hwa Park
- Department of Pathology, Yonsei University Wonju College of Medicine, Wonju, Gangwon, Republic of Korea
| | - Hyeyoung Lee
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Gangwon, Republic of Korea
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250
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Lin Y, Damjanovic A, Metter EJ, Nguyen H, Truong T, Najarro K, Morris C, Longo DL, Zhan M, Ferrucci L, Hodes RJ, Weng NP. Age-associated telomere attrition of lymphocytes in vivo is co-ordinated with changes in telomerase activity, composition of lymphocyte subsets and health conditions. Clin Sci (Lond) 2015; 128:367-77. [PMID: 25317735 PMCID: PMC5421624 DOI: 10.1042/cs20140481] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Telomeres are essential in maintaining chromosome integrity and in controlling cellular replication. Attrition of telomere length in peripheral blood mononuclear cells (PBMCs) with age is well documented from cross-sectional studies. But the actual in vivo changes in telomere lengths and its relationship with the contributing factors within the individuals with age have not been fully addressed. In the present paper, we report a longitudinal analysis of telomere length in the PBMCs, lymphocytes and monocytes of 216 human subjects aged from 20-90 years assessed at 0-, 5- and 12-year follow-up. For the 5- and 12-year follow-up, telomere length in the PBMCs decreased in 34% and 46%, exhibited no detectable change in 56% and 47% and increased in 10% and 7% of the subjects respectively. The rate of telomere change was distinct for T-cells, B-cells and monocytes for any given subject. Telomerase activity declined with age in the resting T-cells and B-cells and the activated T-cells. Finally, a significant portion of telomere attrition in T-cells with age was explained by a decline in the telomerase activity, decreased naïve cells and the change in physiological conditions such as elevated blood glucose and interleukin (IL)-6 levels. These findings show that changes in the telomere length of the PBMCs with age in vivo occur at different rates in different individuals and cell types and reveal that changes in the telomere length in the T-cells with age is influenced by the telomerase activity, naïve T-cell percentage and changes in health conditions.
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Affiliation(s)
- Yun Lin
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, U.S.A
| | - Amanda Damjanovic
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, U.S.A
| | - E. Jeffrey Metter
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224,U.S.A
| | - Huy Nguyen
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, U.S.A
| | - Thai Truong
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, U.S.A
| | - Kevin Najarro
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, U.S.A
| | - Christa Morris
- Flow Cytometry Unit, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, U.S.A
| | - Dan L. Longo
- Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, U.S.A
| | - Ming Zhan
- Bioinformatics Unit, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, U.S.A
| | - Luigi Ferrucci
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224,U.S.A
| | - Richard J. Hodes
- National Institute on Aging and Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, U.S.A
| | - Nan-ping Weng
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, U.S.A
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