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Arias-Salgado EG, Galvez E, Planas-Cerezales L, Pintado-Berninches L, Vallespin E, Martinez P, Carrillo J, Iarriccio L, Ruiz-Llobet A, Catalá A, Badell-Serra I, Gonzalez-Granado LI, Martín-Nalda A, Martínez-Gallo M, Galera-Miñarro A, Rodríguez-Vigil C, Bastos-Oreiro M, Perez de Nanclares G, Leiro-Fernández V, Uria ML, Diaz-Heredia C, Valenzuela C, Martín S, López-Muñiz B, Lapunzina P, Sevilla J, Molina-Molina M, Perona R, Sastre L. Genetic analyses of aplastic anemia and idiopathic pulmonary fibrosis patients with short telomeres, possible implication of DNA-repair genes. Orphanet J Rare Dis 2019; 14:82. [PMID: 30995915 PMCID: PMC6471801 DOI: 10.1186/s13023-019-1046-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/12/2019] [Indexed: 01/19/2023] Open
Abstract
Background Telomeres are nucleoprotein structures present at the terminal region of the chromosomes. Mutations in genes coding for proteins involved in telomere maintenance are causative of a number of disorders known as telomeropathies. The genetic origin of these diseases is heterogeneous and has not been determined for a significant proportion of patients. Methods This article describes the genetic characterization of a cohort of patients. Telomere length was determined by Southern blot and quantitative PCR. Nucleotide variants were analyzed either by high-resolution melting analysis and Sanger sequencing of selected exons or by massive sequencing of a panel of genes. Results Forty-seven patients with telomere length below the 10% of normal population, affected with three telomeropathies: dyskeratosis congenita (4), aplastic anemia (22) or pulmonary fibrosis (21) were analyzed. Eighteen of these patients presented known pathogenic or novel possibly pathogenic variants in the telomere-related genes TERT, TERC, RTEL1, CTC1 and ACD. In addition, the analyses of a panel of 188 genes related to haematological disorders indicated that a relevant proportion of the patients (up to 35%) presented rare variants in genes related to DNA repair or in genes coding for proteins involved in the resolution of complex DNA structures, that participate in telomere replication. Mutations in some of these genes are causative of several syndromes previously associated to telomere shortening. Conclusion Novel variants in telomere, DNA repair and replication genes are described that might indicate the contribution of variants in these genes to the development of telomeropathies. Patients carrying variants in telomere-related genes presented worse evolution after diagnosis than the rest of patients analyzed. Electronic supplementary material The online version of this article (10.1186/s13023-019-1046-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elena G Arias-Salgado
- Instituto de Investigaciones Biomedicas CSIC/UAM, IDIPaz, Arturo Duperier, 4, 28029, Madrid, Spain.,Advanced Medical Projects, Madrid, Spain
| | - Eva Galvez
- Hospital Niño Jesús, Hematología y Hemoterapia, Madrid, Spain
| | - Lurdes Planas-Cerezales
- ILD Unit Pneumology Department, University Hospital of Bellvitge, IDIBELL, University of Barcelona, Barcelona, Spain
| | - Laura Pintado-Berninches
- Instituto de Investigaciones Biomedicas CSIC/UAM, IDIPaz, Arturo Duperier, 4, 28029, Madrid, Spain.,Advanced Medical Projects, Madrid, Spain
| | - Elena Vallespin
- Institute of Medical and Molecular Genetics (INGEMM), Hospital Universitario La Paz, Madrid, Spain
| | - Pilar Martinez
- Institute of Medical and Molecular Genetics (INGEMM), Hospital Universitario La Paz, Madrid, Spain
| | - Jaime Carrillo
- Instituto de Investigaciones Biomedicas CSIC/UAM, IDIPaz, Arturo Duperier, 4, 28029, Madrid, Spain
| | - Laura Iarriccio
- Instituto de Investigaciones Biomedicas CSIC/UAM, IDIPaz, Arturo Duperier, 4, 28029, Madrid, Spain.,Advanced Medical Projects, Madrid, Spain
| | - Anna Ruiz-Llobet
- Pediatric Hematology and Oncology Department, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain.,Institut de Recerca Pediàtrica Hospital Sant Joan de Déu (IRP-HSJD), Esplugues de Llobregat, Barcelona, Spain
| | - Albert Catalá
- Pediatric Hematology and Oncology Department, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain.,Institut de Recerca Pediàtrica Hospital Sant Joan de Déu (IRP-HSJD), Esplugues de Llobregat, Barcelona, Spain
| | | | | | - Andrea Martín-Nalda
- Immunology Division, Pediatric Infectious Diseases and Immunodeficiencies Unit, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Spain
| | - Mónica Martínez-Gallo
- Immunology Division, Pediatric Infectious Diseases and Immunodeficiencies Unit, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Spain
| | | | | | | | - Guiomar Perez de Nanclares
- Molecular (Epi)Genetics Laboratory, BioAraba National Health Institute, OSI Araba University Hospital, Vitoria-Gasteiz, Spain
| | - Virginia Leiro-Fernández
- Pneumology Department, Hospital Álvaro Cunqueiro, Complexo Hospitalario Universitario de Vigo, NeumoVigoI+i Research Group, Vigo Biomedical Research Institute (IBIV), Barcelona, Spain
| | - Maria-Luz Uria
- Immunology Division, Pediatric Infectious Diseases and Immunodeficiencies Unit, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Spain
| | - Cristina Diaz-Heredia
- Immunology Division, Pediatric Infectious Diseases and Immunodeficiencies Unit, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Spain
| | | | - Sara Martín
- ILD Unit Pneumology Department, University Hospital of Bellvitge, IDIBELL, University of Barcelona, Barcelona, Spain
| | | | - Pablo Lapunzina
- Institute of Medical and Molecular Genetics (INGEMM), Hospital Universitario La Paz, Madrid, Spain.,CIBER de enfermedades raras (CIBERER), Madrid, Spain
| | - Julian Sevilla
- Hospital Niño Jesús, Hematología y Hemoterapia, Madrid, Spain.,CIBER de enfermedades raras (CIBERER), Madrid, Spain
| | - María Molina-Molina
- ILD Unit Pneumology Department, University Hospital of Bellvitge, IDIBELL, University of Barcelona, Barcelona, Spain.,CIBER of Respiratory diseases (CIBERES), Barcelona, Spain
| | - Rosario Perona
- Instituto de Investigaciones Biomedicas CSIC/UAM, IDIPaz, Arturo Duperier, 4, 28029, Madrid, Spain.,CIBER de enfermedades raras (CIBERER), Madrid, Spain
| | - Leandro Sastre
- Instituto de Investigaciones Biomedicas CSIC/UAM, IDIPaz, Arturo Duperier, 4, 28029, Madrid, Spain. .,CIBER de enfermedades raras (CIBERER), Madrid, Spain.
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The Emerging Roles of TERRA in Telomere Maintenance and Genome Stability. Cells 2019; 8:cells8030246. [PMID: 30875900 PMCID: PMC6468625 DOI: 10.3390/cells8030246] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/08/2019] [Accepted: 03/12/2019] [Indexed: 12/20/2022] Open
Abstract
The finding that transcription occurs at chromosome ends has opened new fields of study on the roles of telomeric transcripts in chromosome end maintenance and genome stability. Indeed, the ends of chromosomes are required to be protected from activation of DNA damage response and DNA repair pathways. Chromosome end protection is achieved by the activity of specific proteins that associate with chromosome ends, forming telomeres. Telomeres need to be constantly maintained as they are in a heterochromatic state and fold into specific structures (T-loops), which may hamper DNA replication. In addition, in the absence of maintenance mechanisms, chromosome ends shorten at every cell division due to limitations in the DNA replication machinery, which is unable to fully replicate the extremities of chromosomes. Altered telomere structure or critically short chromosome ends generate dysfunctional telomeres, ultimately leading to replicative senescence or chromosome instability. Telomere biology is thus implicated in multiple human diseases, including cancer. Emerging evidence indicates that a class of long noncoding RNAs transcribed at telomeres, known as TERRA for “TElomeric Repeat-containing RNA,” actively participates in the mechanisms regulating telomere maintenance and chromosome end protection. However, the molecular details of TERRA activities remain to be elucidated. In this review, we discuss recent findings on the emerging roles of TERRA in telomere maintenance and genome stability and their implications in human diseases.
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c-Myc activation promotes cofilin-mediated F-actin cytoskeleton remodeling and telomere homeostasis as a response to oxidant-based DNA damage in medulloblastoma cells. Redox Biol 2019; 24:101163. [PMID: 30901604 PMCID: PMC6429558 DOI: 10.1016/j.redox.2019.101163] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 03/07/2019] [Indexed: 01/22/2023] Open
Abstract
Medulloblastoma (MB) is a common and highly aggressive pediatric brain tumor of a heterogeneous nature. According to transcriptome-based profiling, four molecular subgroups of MB have been revealed, namely WNT, SHH, Group 3 and Group 4. High MYC mRNA expression and MYC gene amplification in MB have been considered as indicators of poor prognosis. However, the role of c-Myc in MB biology is still not well established. In the present study, the effects of c-Myc activation in UW228-MycER MB cell line were investigated using 4-hydroxytamoxifen (4-OHT) induction system. Upon 4-OHT stimulation, an increase in metabolic activity, large-cell/anaplastic (LC/A) phenotype and oxidative stress-mediated DNA damage were observed. However, 53BP1 foci were not implicated in DNA damage response. Instead, cofilin nuclear translocation, changes in F-actin cytoskeleton and the levels of cytoskeletal proteins were shown. Moreover, the telomere length was found to be unaffected that may be associated with the upregulation of TRF proteins. Transcription of nascent RNA (synthesis of new rRNA) and the expression of RNA polymerase I-specific transcription initiation factor RRN3/TIF-IA were also elevated. Moreover, increased levels of DNMT2, a modulator of stress responses, were observed. A small fraction of cells responded differently as oncogene-induced senescence was also noticed. We postulate that c-Myc-mediated modulation of genetic stability of MB cells may trigger cellular heterogeneity and affect adaptive responses to changing environment.
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Telomeres in Plants and Humans: Not So Different, Not So Similar. Cells 2019; 8:cells8010058. [PMID: 30654521 PMCID: PMC6356271 DOI: 10.3390/cells8010058] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/07/2019] [Accepted: 01/07/2019] [Indexed: 01/01/2023] Open
Abstract
Parallel research on multiple model organisms shows that while some principles of telomere biology are conserved among all eukaryotic kingdoms, we also find some deviations that reflect different evolutionary paths and life strategies, which may have diversified after the establishment of telomerase as a primary mechanism for telomere maintenance. Much more than animals, plants have to cope with environmental stressors, including genotoxic factors, due to their sessile lifestyle. This is, in principle, made possible by an increased capacity and efficiency of the molecular systems ensuring maintenance of genome stability, as well as a higher tolerance to genome instability. Furthermore, plant ontogenesis differs from that of animals in which tissue differentiation and telomerase silencing occur during early embryonic development, and the “telomere clock” in somatic cells may act as a preventive measure against carcinogenesis. This does not happen in plants, where growth and ontogenesis occur through the serial division of apical meristems consisting of a small group of stem cells that generate a linear series of cells, which differentiate into an array of cell types that make a shoot and root. Flowers, as generative plant organs, initiate from the shoot apical meristem in mature plants which is incompatible with the human-like developmental telomere shortening. In this review, we discuss differences between human and plant telomere biology and the implications for aging, genome stability, and cell and organism survival. In particular, we provide a comprehensive comparative overview of telomere proteins acting in humans and in Arabidopsis thaliana model plant, and discuss distinct epigenetic features of telomeric chromatin in these species.
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Kong X, Cruz GMS, Trinh SL, Zhu XD, Berns MW, Yokomori K. Biphasic recruitment of TRF2 to DNA damage sites promotes non-sister chromatid homologous recombination repair. J Cell Sci 2018; 131:jcs219311. [PMID: 30404833 PMCID: PMC10682959 DOI: 10.1242/jcs.219311] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 10/30/2018] [Indexed: 11/30/2023] Open
Abstract
TRF2 (TERF2) binds to telomeric repeats and is critical for telomere integrity. Evidence suggests that it also localizes to non-telomeric DNA damage sites. However, this recruitment appears to be precarious and functionally controversial. We find that TRF2 recruitment to damage sites occurs by a two-step mechanism: the initial rapid recruitment (phase I), and stable and prolonged association with damage sites (phase II). Phase I is poly(ADP-ribose) polymerase (PARP)-dependent and requires the N-terminal basic domain. The phase II recruitment requires the C-terminal MYB/SANT domain and the iDDR region in the hinge domain, which is mediated by the MRE11 complex and is stimulated by TERT. PARP-dependent recruitment of intrinsically disordered proteins contributes to transient displacement of TRF2 that separates two phases. TRF2 binds to I-PpoI-induced DNA double-strand break sites, which is enhanced by the presence of complex damage and is dependent on PARP and the MRE11 complex. TRF2 depletion affects non-sister chromatid homologous recombination repair, but not homologous recombination between sister chromatids or non-homologous end-joining pathways. Our results demonstrate a unique recruitment mechanism and function of TRF2 at non-telomeric DNA damage sites.
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Affiliation(s)
- Xiangduo Kong
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700, USA
| | - Gladys Mae Saquilabon Cruz
- Beckman Laser Institute and Medical Clinic, University of California, Irvine, 1002 Health Sciences Road East, Irvine, CA 92612, USA
| | - Sally Loyal Trinh
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700, USA
| | - Xu-Dong Zhu
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Michael W Berns
- Beckman Laser Institute and Medical Clinic, University of California, Irvine, 1002 Health Sciences Road East, Irvine, CA 92612, USA
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, CA 92617, USA
- Department of Biomedical Engineering and Surgery, University of California, Irvine, CA 92617, USA
| | - Kyoko Yokomori
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700, USA
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Sierant ML, Davey SK. Identification and characterization of a novel nuclear structure containing members of the homologous recombination and DNA damage response pathways. Cancer Genet 2018; 228-229:98-109. [DOI: 10.1016/j.cancergen.2018.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/06/2018] [Accepted: 10/12/2018] [Indexed: 12/22/2022]
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57
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Mukherjee AK, Sharma S, Sengupta S, Saha D, Kumar P, Hussain T, Srivastava V, Roy SD, Shay JW, Chowdhury S. Telomere length-dependent transcription and epigenetic modifications in promoters remote from telomere ends. PLoS Genet 2018; 14:e1007782. [PMID: 30439955 PMCID: PMC6264879 DOI: 10.1371/journal.pgen.1007782] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 11/29/2018] [Accepted: 10/23/2018] [Indexed: 12/03/2022] Open
Abstract
Telomere-binding proteins constituting the shelterin complex have been studied primarily for telomeric functions. However, mounting evidence shows non-telomeric binding and gene regulation by shelterin factors. This raises a key question—do telomeres impact binding of shelterin proteins at distal non-telomeric sites? Here we show that binding of the telomere-repeat-binding-factor-2 (TRF2) at promoters ~60 Mb from telomeres depends on telomere length in human cells. Promoter TRF2 occupancy was depleted in cells with elongated telomeres resulting in altered TRF2-mediated transcription of distal genes. In addition, histone modifications—activation (H3K4me1 and H3K4me3) as well as silencing marks (H3K27me3)—at distal promoters were telomere length-dependent. These demonstrate that transcription, and the epigenetic state, of telomere-distal promoters can be influenced by telomere length. Molecular links between telomeres and the extra-telomeric genome, emerging from findings here, might have important implications in telomere-related physiology, particularly ageing and cancer. Telomeres (special DNA-protein assemblies that protect chromosome ends) affect ageing and diseases such as cancer. Although this has been recognized for many years, biological processes that connect telomeres to ageing, cancer and other cellular functions remain to be fully understood. Certain proteins, believed to be only telomere-associated, engage DNA outside telomeres. This raises an interesting question. Does telomere length influence how telomere-binding proteins associate with DNA at regions distal from telomeres. If so, how does this impact function? Motivated by these questions, in the present studies we tested if extra-telomeric binding of the well-known telomere-repeat-binding-actor-2 (TRF2) depends on telomere length. Our results show that the level of DNA-bound TRF2 at telomere-distal sites changes as telomeres shorten or elongate. Consequently, TRF2-mediated gene regulation affects many genes. Notably, histone modifications that dictate chromatin compaction and access to regulatory factors, at sites distant from telomere ends also depended on telomere length. Together, this links the state of telomeres to gene regulation and epigenetics directly in ways not previously appreciated that might impact a more complete understanding of molecular processes underlying ageing and cancer.
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Affiliation(s)
- Ananda Kishore Mukherjee
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
- Academy of Scientific and Innovative Research, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Shalu Sharma
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
- Academy of Scientific and Innovative Research, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Suman Sengupta
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Dhurjhoti Saha
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Pankaj Kumar
- Academy of Scientific and Innovative Research, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
- G.N.R. Knowledge Centre for Genome Informatics, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Tabish Hussain
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Vivek Srivastava
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Sumitabho Deb Roy
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Jerry W. Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Shantanu Chowdhury
- Genomics and Molecular Medicine Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
- Academy of Scientific and Innovative Research, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
- G.N.R. Knowledge Centre for Genome Informatics, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
- * E-mail:
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Abstract
For more than a decade, it has been known that mammalian cells use shelterin to protect chromosome ends. Much progress has been made on the mechanism by which shelterin prevents telomeres from inadvertently activating DNA damage signaling and double-strand break (DSB) repair pathways. Shelterin averts activation of three DNA damage response enzymes [the ataxia-telangiectasia-mutated (ATM) and ataxia telangiectasia and Rad3-related (ATR) kinases and poly(ADP-ribose) polymerase 1 (PARP1)], blocks three DSB repair pathways [classical nonhomologous end joining (c-NHEJ), alternative (alt)-NHEJ, and homology-directed repair (HDR)], and prevents hyper-resection at telomeres. For several of these functions, mechanistic insights have emerged. In addition, much has been learned about how shelterin maintains the telomeric 3' overhang, forms and protects the t-loop structure, and promotes replication through telomeres. These studies revealed that shelterin is compartmentalized, with individual subunits dedicated to distinct aspects of the end-protection problem. This review focuses on the current knowledge of shelterin-mediated telomere protection, highlights differences between human and mouse shelterin, and discusses some of the questions that remain.
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Affiliation(s)
- Titia de Lange
- Laboratory of Cell Biology and Genetics, Rockefeller University, New York, NY 10065, USA;
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Saker L, Ali S, Masserot C, Kellermann G, Poupon J, Teulade-Fichou MP, Ségal-Bendirdjian E, Bombard S. Platinum Complexes Can Bind to Telomeres by Coordination. Int J Mol Sci 2018; 19:E1951. [PMID: 29970863 PMCID: PMC6073198 DOI: 10.3390/ijms19071951] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 06/27/2018] [Accepted: 06/29/2018] [Indexed: 01/07/2023] Open
Abstract
It is suggested that several compounds, including G-quadruplex ligands, can target telomeres, inducing their uncapping and, ultimately, cell death. However, it has never been demonstrated whether such ligands can bind directly and quantitatively to telomeres. Here, we employed the property of platinum and platinum-G-quadruplex complexes to target G-rich sequences to investigate and quantify their covalent binding to telomeres. Using inductively coupled plasma mass spectrometry, surprisingly, we found that, in cellulo, in the presence of cisplatin, a di-functional platinum complex, telomeric DNA was platinated 13-times less than genomic DNA in cellulo, as compared to in vitro data. On the contrary, the amount of mono-functional platinum complexes (Pt-ttpy and Pt-tpy) bound either to telomeric or to genomic DNA was similar and occurred in a G-quadruplex independent-manner. Importantly, the quantification revealed that the low level of cisplatin bound to telomeric DNA could not be the direct physical cause of TRF2 displacement from telomeres. Altogether, our data suggest that platinum complexes can affect telomeres both directly and indirectly.
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Affiliation(s)
- Lina Saker
- INSERM UMR-S 1007, Cellular Homeostasis and Cancer, 75006 Paris, France.
- Paris Descartes University, Paris Sorbonne Cité, 75006 Paris, France.
| | - Samar Ali
- INSERM UMR-S 1007, Cellular Homeostasis and Cancer, 75006 Paris, France.
- Paris Sud University, Paris-Saclay University, 91405 Orsay, France.
| | - Caroline Masserot
- INSERM UMR-S 1007, Cellular Homeostasis and Cancer, 75006 Paris, France.
- Paris Sud University, Paris-Saclay University, 91405 Orsay, France.
| | - Guillaume Kellermann
- INSERM UMR-S 1007, Cellular Homeostasis and Cancer, 75006 Paris, France.
- Paris Descartes University, Paris Sorbonne Cité, 75006 Paris, France.
| | - Joel Poupon
- Laboratoire de Toxicologie-Biologique, Hôpital Lariboisière, 2 rue Ambroise Paré, 75475 Paris, France.
| | - Marie-Paule Teulade-Fichou
- Paris Sud University, Paris-Saclay University, 91405 Orsay, France.
- Institut Curie-Recherche, Bât. 112, Centre Universitaire, 91405 Orsay, France.
- CNRS UMR918, Centre Universitaire, 91405 Orsay, France.
- INSERM U1196, Centre Universitaire, 91405 Orsay, France.
| | - Evelyne Ségal-Bendirdjian
- INSERM UMR-S 1007, Cellular Homeostasis and Cancer, 75006 Paris, France.
- Paris Descartes University, Paris Sorbonne Cité, 75006 Paris, France.
- Paris Sud University, Paris-Saclay University, 91405 Orsay, France.
| | - Sophie Bombard
- INSERM UMR-S 1007, Cellular Homeostasis and Cancer, 75006 Paris, France.
- Paris Descartes University, Paris Sorbonne Cité, 75006 Paris, France.
- Paris Sud University, Paris-Saclay University, 91405 Orsay, France.
- Institut Curie-Recherche, Bât. 112, Centre Universitaire, 91405 Orsay, France.
- CNRS UMR918, Centre Universitaire, 91405 Orsay, France.
- INSERM U1196, Centre Universitaire, 91405 Orsay, France.
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da Silva Neto Trajano LA, Trajano ETL, da Silva Sergio LP, Teixeira AF, Mencalha AL, Stumbo AC, de Souza da Fonseca A. Photobiomodulation effects on mRNA levels from genomic and chromosome stabilization genes in injured muscle. Lasers Med Sci 2018; 33:1513-1519. [DOI: 10.1007/s10103-018-2510-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 04/17/2018] [Indexed: 01/09/2023]
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Rain M, Chaudhary H, Kukreti R, Thinlas T, Mohammad G, Pasha Q. Elevated Vasodilatory Cyclases and Shorter Telomere Length Contribute to High-Altitude Pulmonary Edema. High Alt Med Biol 2018; 19:60-68. [PMID: 29443612 DOI: 10.1089/ham.2017.0136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Rain, Manjari, Himanshi Chaudhary, Ritushree Kukreti, Tashi Thinlas, Ghulam Mohammad, and Qadar Pasha. Elevated vasodilatory cyclases and shorter telomere length contribute to high-altitude pulmonary edema. High Alt Med Biol. 19:60-68, 2018. AIM High-altitude (HA) genetics is complex with respect to health and disease (HA pulmonary edema i.e., HAPE). Based on the widely recognized fact that oxidative stress is a major trigger of several physiological processes, this study was designed to establish the significance of vasodilatory cyclases and telomere length in HA physiology. The study was performed in three groups, namely HAPE-free sojourners (HAPE-f, n = 150), HAPE patients (HAPE-p, n = 150), and healthy highland natives or highlanders (HLs, n = 150). Variations in soluble guanylyl cyclase β1-subunit (GUCY1B3) and adenylyl cyclase type 6 (ADCY6) were genotyped by the SNaPshot method and/or Fluidigm SNP type genotyping. Plasma GUCY1B3 and ADCY6 levels were estimated using ELISA, and relative telomere length was estimated by qRT-PCR. RESULTS The rs7638AA genotype was over-represented in HLs compared with HAPE-f and HAPE-p (p = 0.035 and p = 0.012, respectively). Similarly, the rs7638A allele was prevalent in HLs compared with both groups, but significance was attained against HAPE-p (p = 0.012). Significantly elevated plasma levels of GUCY1B3 and ADCY6 were obtained in HAPE-p compared with HAPE-f (p = 0.001 and p = 0.006, respectively) and HLs (p = 3.31E-05 and p = 0.05, respectively). Shorter telomere length was observed in HAPE-p compared with HAPE-f (p > 0.05) and HLs (p = 0.017). CONCLUSION Elevated cyclases and shorter telomere length associate with HAPE pathophysiology.
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Affiliation(s)
- Manjari Rain
- 1 CSIR-Institute of Genomics and Integrative Biology , Delhi, India .,2 Academy of Scientific and Innovative Research , New Delhi, India
| | | | - Ritushree Kukreti
- 1 CSIR-Institute of Genomics and Integrative Biology , Delhi, India .,2 Academy of Scientific and Innovative Research , New Delhi, India
| | - Tashi Thinlas
- 3 Department of Medicine, Sonam Norboo Memorial Hospital , Leh, Ladakh, Jammu and Kashmir, India
| | - Ghulam Mohammad
- 3 Department of Medicine, Sonam Norboo Memorial Hospital , Leh, Ladakh, Jammu and Kashmir, India
| | - Qadar Pasha
- 1 CSIR-Institute of Genomics and Integrative Biology , Delhi, India .,4 Indian Council of Medical Research , New Delhi, India
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Li JSZ, Denchi EL. How stem cells keep telomeres in check. Differentiation 2018; 100:21-25. [PMID: 29413749 DOI: 10.1016/j.diff.2018.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 01/19/2018] [Accepted: 01/23/2018] [Indexed: 10/18/2022]
Abstract
In multicellular organisms, regulation of telomere length in pluripotent stem cells is critical to ensure organism development and survival. Telomeres consist of repetitive DNA that are progressively lost with each cellular division. When telomeres become critically short, they activate a DNA damage response that results in cell cycle arrest. To counteract telomere attrition, pluripotent stem cells are equipped with telomere elongation mechanisms that ensure prolonged proliferation capacity and self-renewal capacity. Excessive telomere elongation can also be deleterious and is counteracted by a rapid telomere deletion mechanism termed telomere trimming. While the consequences of critically short telomeres are well established, we are only beginning to understand the mechanisms that counteract excessive telomere elongation. The balance between telomere elongation and shortening determine the telomere length set point in pluripotent stem cells and ensures sustained proliferative potential without causing chromosome instability.
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Affiliation(s)
- Julia Su Zhou Li
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Eros Lazzerini Denchi
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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63
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Curigliano G. Targeting DNA Repair. Handb Exp Pharmacol 2018; 249:161-180. [PMID: 30341723 DOI: 10.1007/164_2017_31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Genomic instability is a characteristic of most human cancers and plays critical roles in both cancer development and progression. There are various forms of genomic instability arising from many different pathways, such as DNA damage from endogenous and exogenous sources, centrosome amplification, telomere damage, and epigenetic modifications. DNA-repair pathways can enable tumor cells to survive DNA damage. The failure to respond to DNA damage is a characteristic associated with genomic instability. Understanding of genomic instability in cancer is still very limited, but the further understanding of the molecular mechanisms through which the DNA damage response (DDR) operates, in combination with the elucidation of the genetic interactions between DDR pathways and other cell pathways, will provide therapeutic opportunities for the personalized medicine of cancer.
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Affiliation(s)
- Giuseppe Curigliano
- Early Drug Development for Innovative Therapy Division, European Institute of Oncology, Via Ripamonti, 435 20141, Milan, Italy.
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64
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Natarajan S, Begum F, Gim J, Wark L, Henderson D, Davie JR, Hombach-Klonisch S, Klonisch T. High Mobility Group A2 protects cancer cells against telomere dysfunction. Oncotarget 2017; 7:12761-82. [PMID: 26799419 PMCID: PMC4914320 DOI: 10.18632/oncotarget.6938] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 12/07/2015] [Indexed: 11/25/2022] Open
Abstract
The non-histone chromatin binding protein High Mobility Group AT-hook protein 2 (HMGA2) plays important roles in the repair and protection of genomic DNA in embryonic stem cells and cancer cells. Here we show that HMGA2 localizes to mammalian telomeres and enhances telomere stability in cancer cells. We present a novel interaction of HMGA2 with the key shelterin protein TRF2. We found that the linker (L1) region of HMGA2 contributes to this interaction but the ATI-L1-ATII molecular region of HMGA2 is required for strong interaction with TRF2. This interaction was independent of HMGA2 DNA-binding and did not require the TRF2 interacting partner RAP1 but involved the homodimerization and hinge regions of TRF2. HMGA2 retained TRF2 at telomeres and reduced telomere-dysfunction despite induced telomere stress. Silencing of HMGA2 resulted in (i) reduced binding of TRF2 to telomere DNA as observed by ChIP, (ii) increased telomere instability and (iii) the formation of telomere dysfunction-induced foci (TIF). This resulted in increased telomere aggregation, anaphase bridges and micronuclei. HMGA2 prevented ATM-dependent pTRF2T188 phosphorylation and attenuated signaling via the telomere specific ATM-CHK2-CDC25C DNA damage signaling axis. In summary, our data demonstrate a unique and novel role of HMGA2 in telomere protection and promoting telomere stability in cancer cells. This identifies HMGA2 as a new therapeutic target for the destabilization of telomeres in HMGA2+ cancer cells.
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Affiliation(s)
- Suchitra Natarajan
- Department of Human Anatomy and Cell Science, College of Medicine, University of Manitoba, Winnipeg, Canada
| | - Farhana Begum
- Department of Human Anatomy and Cell Science, College of Medicine, University of Manitoba, Winnipeg, Canada
| | - Jeonga Gim
- Department of Human Anatomy and Cell Science, College of Medicine, University of Manitoba, Winnipeg, Canada
| | - Landon Wark
- Department of Human Anatomy and Cell Science, College of Medicine, University of Manitoba, Winnipeg, Canada
| | - Dana Henderson
- Department of Human Anatomy and Cell Science, College of Medicine, University of Manitoba, Winnipeg, Canada
| | - James R Davie
- Children's Hospital Research Institute of Manitoba, Winnipeg, Canada.,Department of Biochemistry and Medical Genetics, College of Medicine, University of Manitoba, Winnipeg, Canada
| | - Sabine Hombach-Klonisch
- Department of Human Anatomy and Cell Science, College of Medicine, University of Manitoba, Winnipeg, Canada.,Department of Obstetrics, Gynecology and Reproductive Medicine, College of Medicine, University of Manitoba, Winnipeg, Canada
| | - Thomas Klonisch
- Department of Human Anatomy and Cell Science, College of Medicine, University of Manitoba, Winnipeg, Canada.,Department of Surgery, College of Medicine, University of Manitoba, Winnipeg, Canada.,Department of Medical Microbiology and Infectious Diseases, College of Medicine, University of Manitoba, Winnipeg, Canada
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65
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Lian S, Meng L, Yang Y, Ma T, Xing X, Feng Q, Song Q, Liu C, Tian Z, Qu L, Shou C. PRL-3 promotes telomere deprotection and chromosomal instability. Nucleic Acids Res 2017; 45:6546-6571. [PMID: 28482095 PMCID: PMC5499835 DOI: 10.1093/nar/gkx392] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 04/26/2017] [Indexed: 12/24/2022] Open
Abstract
Phosphatase of regenerating liver (PRL-3) promotes cell invasiveness, but its role in genomic integrity remains unknown. We report here that shelterin component RAP1 mediates association between PRL-3 and TRF2. In addition, TRF2 and RAP1 assist recruitment of PRL-3 to telomeric DNA. Silencing of PRL-3 in colon cancer cells does not affect telomere integrity or chromosomal stability, but induces reactive oxygen species-dependent DNA damage response and senescence. However, overexpression of PRL-3 in colon cancer cells and primary fibroblasts promotes structural abnormalities of telomeres, telomere deprotection, DNA damage response, chromosomal instability and senescence. Furthermore, PRL-3 dissociates RAP1 and TRF2 from telomeric DNA in vitro and in cells. PRL-3-promoted telomere deprotection, DNA damage response and senescence are counteracted by disruption of PRL-3–RAP1 complex or expression of ectopic TRF2. Examination of clinical samples showed that PRL-3 status positively correlates with telomere deprotection and senescence. PRL-3 transgenic mice exhibit hallmarks of telomere deprotection and senescence and are susceptible to dextran sodium sulfate-induced colon malignancy. Our results uncover a novel role of PRL-3 in tumor development through its adverse impact on telomere homeostasis.
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Affiliation(s)
- Shenyi Lian
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China.,Department of Pathology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Lin Meng
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Yongyong Yang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Ting Ma
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Xiaofang Xing
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Qin Feng
- Central Laboratory, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Qian Song
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Caiyun Liu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Zhihua Tian
- Central Laboratory, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Like Qu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Chengchao Shou
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
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66
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Muraki K, Murnane JP. The DNA damage response at dysfunctional telomeres, and at interstitial and subtelomeric DNA double-strand breaks. Genes Genet Syst 2017; 92:135-152. [PMID: 29162774 DOI: 10.1266/ggs.17-00014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In mammals, DNA double-strand breaks (DSBs) are primarily repaired by classical non-homologous end joining (C-NHEJ), although homologous recombination repair and alternative NHEJ (A-NHEJ), which involve DSB processing, can also occur. These pathways are tightly regulated to maintain chromosome integrity. The ends of chromosomes, called telomeres, contain telomeric DNA that forms a cap structure in cooperation with telomeric proteins to prevent the activation of the DNA damage response and chromosome fusion at chromosome termini. Telomeres and subtelomeric regions are poor substrates for DNA replication; therefore, regions near telomeres are prone to replication fork stalling and chromosome breakage. Moreover, DSBs near telomeres are poorly repaired. As a result, when DSBs occur near telomeres in normal cells, the cells stop proliferating, while in cancer cells, subtelomeric DSBs induce rearrangements due to the absence of cell cycle checkpoints. The sensitivity of subtelomeric regions to DSBs is due to the improper regulation of processing, because although C-NHEJ is functional at subtelomeric DSBs, excessive processing results in an increased frequency of large deletions and chromosome rearrangements involving A-NHEJ.
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Affiliation(s)
- Keiko Muraki
- Institute for Protein Research, Osaka University.,Department of Radiation Oncology, University of California, San Francisco
| | - John P Murnane
- Department of Radiation Oncology, University of California, San Francisco
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67
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Erdel F, Kratz K, Willcox S, Griffith JD, Greene EC, de Lange T. Telomere Recognition and Assembly Mechanism of Mammalian Shelterin. Cell Rep 2017; 18:41-53. [PMID: 28052260 DOI: 10.1016/j.celrep.2016.12.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/13/2016] [Accepted: 11/30/2016] [Indexed: 11/16/2022] Open
Abstract
Shelterin is a six-subunit protein complex that plays crucial roles in telomere length regulation, protection, and maintenance. Although several shelterin subunits have been studied in vitro, the biochemical properties of the fully assembled shelterin complex are not well defined. Here, we characterize shelterin using ensemble biochemical methods, electron microscopy, and single-molecule imaging to determine how shelterin recognizes and assembles onto telomeric repeats. We show that shelterin complexes can exist in solution and primarily locate telomeric DNA through a three-dimensional diffusive search. Shelterin can diffuse along non-telomeric DNA but is impeded by nucleosomes, arguing against extensive one-dimensional diffusion as a viable assembly mechanism. Our work supports a model in which individual shelterin complexes rapidly bind to telomeric repeats as independent functional units, which do not alter the DNA-binding mode of neighboring complexes but, rather, occupy telomeric DNA in a "beads on a string" configuration.
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Affiliation(s)
- Fabian Erdel
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Katja Kratz
- Laboratory for Cell Biology and Genetics, Rockefeller University, New York, NY 10065, USA
| | - Smaranda Willcox
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jack D Griffith
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Eric C Greene
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, Rockefeller University, New York, NY 10065, USA.
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68
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Telomere-Internal Double-Strand Breaks Are Repaired by Homologous Recombination and PARP1/Lig3-Dependent End-Joining. Cell Rep 2017; 17:1646-1656. [PMID: 27806302 DOI: 10.1016/j.celrep.2016.10.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/06/2016] [Accepted: 10/03/2016] [Indexed: 01/29/2023] Open
Abstract
Shelterin protects chromosome ends from the DNA damage response. Although the mechanism of telomere protection has been studied extensively, the fate of double-strand breaks (DSBs) inside telomeres is not known. Here, we report that telomere-internal FokI-induced DSBs activate ATM kinase-dependent signaling in S-phase but are well tolerated and repaired efficiently. Homologous recombination contributes to repair, leading to increased telomere length heterogeneity typical of the alternative lengthening of telomeres (ALT) pathway. Furthermore, cells accumulate extra chromosomal telomeric signals (ECTS), a second hallmark of ALT. Telomere-internal DSBs are also repaired by a PARP1- and Ligase3-dependent reaction, suggesting alternative non-homologous end-joining (alt-NHEJ), which relies on microhomology at DSBs. However, as resected telomere-internal DSBs have perfect homology, their PARP1/Lig3-dependent end-joining may be more akin to single strand break repair. We conclude that shelterin does not repress ATM kinase signaling or DSB repair at telomere-internal sites, thereby allowing DNA repair to maintain telomere integrity.
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69
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Lim CJ, Zaug AJ, Kim HJ, Cech TR. Reconstitution of human shelterin complexes reveals unexpected stoichiometry and dual pathways to enhance telomerase processivity. Nat Commun 2017; 8:1075. [PMID: 29057866 PMCID: PMC5651854 DOI: 10.1038/s41467-017-01313-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 09/07/2017] [Indexed: 01/24/2023] Open
Abstract
The human shelterin proteins associate with telomeric DNA to confer telomere protection and length regulation. They are thought to form higher-order protein complexes for their functions, but studies of shelterin proteins have been mostly limited to pairs of proteins. Here we co-express various human shelterin proteins and find that they form defined multi-subunit complexes. A complex harboring both TRF2 and POT1 has the strongest binding affinity to telomeric DNA substrates comprised of double-stranded DNA with a 3′ single-stranded extension. TRF2 interacts with TIN2 with an unexpected 2:1 stoichiometry in the context of shelterin (RAP12:TRF22:TIN21:TPP11:POT11). Tethering of TPP1 to the telomere either via TRF2–TIN2 or via POT1 gives equivalent enhancement of telomerase processivity. We also identify a peptide region from TPP1 that is both critical and sufficient for TIN2 interaction. Our findings reveal new information about the architecture of human shelterin and how it performs its functions at telomeres. The human shelterin complex protects telomere ends from being recognized as damaged DNA sites and regulates telomere length in conjunction with telomerase. Here the authors establish the stoichiometries of human shelterin complexes of various compositions and show shelterin provides dual pathways to stimulate telomerase processivity.
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Affiliation(s)
- Ci Ji Lim
- Howard Hughes Medical Institute, University of Colorado BioFrontiers Institute, Boulder, CO, 80309, USA.,Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO, 80309, USA
| | - Arthur J Zaug
- Howard Hughes Medical Institute, University of Colorado BioFrontiers Institute, Boulder, CO, 80309, USA.,Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO, 80309, USA
| | - Hee Jin Kim
- Howard Hughes Medical Institute, University of Colorado BioFrontiers Institute, Boulder, CO, 80309, USA.,Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO, 80309, USA
| | - Thomas R Cech
- Howard Hughes Medical Institute, University of Colorado BioFrontiers Institute, Boulder, CO, 80309, USA. .,Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO, 80309, USA.
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70
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Rizzo A, Iachettini S, Salvati E, Zizza P, Maresca C, D'Angelo C, Benarroch-Popivker D, Capolupo A, Del Gaudio F, Cosconati S, Di Maro S, Merlino F, Novellino E, Amoreo CA, Mottolese M, Sperduti I, Gilson E, Biroccio A. SIRT6 interacts with TRF2 and promotes its degradation in response to DNA damage. Nucleic Acids Res 2017; 45:1820-1834. [PMID: 27923994 PMCID: PMC5389694 DOI: 10.1093/nar/gkw1202] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/18/2016] [Indexed: 12/29/2022] Open
Abstract
Telomere repeat binding factor 2 (TRF2) has been increasingly recognized to be involved in telomere maintenance and DNA damage response. Here, we show that TRF2 directly binds SIRT6 in a DNA independent manner and that this interaction is increased upon replication stress. Knockdown of SIRT6 up-regulates TRF2 protein levels and counteracts its down-regulation during DNA damage response, leading to cell survival. Moreover, we report that SIRT6 deactetylates in vivo the TRFH domain of TRF2, which in turn, is ubiquitylated in vivo activating the ubiquitin-dependent proteolysis. Notably, overexpression of the TRF2cT mutant failed to be stabilized by SIRT6 depletion, demonstrating that the TRFH domain is required for its post-transcriptional modification. Finally, we report an inverse correlation between SIRT6 and TRF2 protein expression levels in a cohort of colon rectal cancer patients. Taken together our findings describe TRF2 as a novel SIRT6 substrate and demonstrate that acetylation of TRF2 plays a crucial role in the regulation of TRF2 protein stability, thus providing a new route for modulating its expression level during oncogenesis and damage response.
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Affiliation(s)
- Angela Rizzo
- Oncogenomic and Epigenetic Unit, Regina Elena National Cancer Institute, Via Elio Chianesi 53, Rome 00144, Italy
| | - Sara Iachettini
- Oncogenomic and Epigenetic Unit, Regina Elena National Cancer Institute, Via Elio Chianesi 53, Rome 00144, Italy
| | - Erica Salvati
- Oncogenomic and Epigenetic Unit, Regina Elena National Cancer Institute, Via Elio Chianesi 53, Rome 00144, Italy
| | - Pasquale Zizza
- Oncogenomic and Epigenetic Unit, Regina Elena National Cancer Institute, Via Elio Chianesi 53, Rome 00144, Italy
| | - Carmen Maresca
- Oncogenomic and Epigenetic Unit, Regina Elena National Cancer Institute, Via Elio Chianesi 53, Rome 00144, Italy
| | - Carmen D'Angelo
- Oncogenomic and Epigenetic Unit, Regina Elena National Cancer Institute, Via Elio Chianesi 53, Rome 00144, Italy
| | - Delphine Benarroch-Popivker
- Université Côte d'Azur, INSERM U1081 CNRS UMR7284, Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, France
| | - Angela Capolupo
- Department of Pharmacy, PhD Program in Drug Discovery and Development, University of Salerno, Via Giovanni Paolo II 132, Fisciano (SA) 84084, Italy
| | - Federica Del Gaudio
- Department of Pharmacy, PhD Program in Drug Discovery and Development, University of Salerno, Via Giovanni Paolo II 132, Fisciano (SA) 84084, Italy
| | - Sandro Cosconati
- DiSTABiF, Seconda Università di Napoli, Via Vivaldi 43, Caserta 81100, Italy
| | - Salvatore Di Maro
- DiSTABiF, Seconda Università di Napoli, Via Vivaldi 43, Caserta 81100, Italy
| | - Francesco Merlino
- Department of Pharmacy, University of Naples Federico II, Via Montesano 49, Naples 80131, Italy
| | - Ettore Novellino
- Department of Pharmacy, University of Naples Federico II, Via Montesano 49, Naples 80131, Italy
| | - Carla Azzurra Amoreo
- Department of Pathology, Regina Elena National Cancer Institute, Via Elio Chianesi 53, Rome 00144, Italy
| | - Marcella Mottolese
- Department of Pathology, Regina Elena National Cancer Institute, Via Elio Chianesi 53, Rome 00144, Italy
| | - Isabella Sperduti
- Biostatistics Unit, Regina Elena National Cancer Institute, Via Elio Chianesi 53, Rome 00144, Italy
| | - Eric Gilson
- Université Côte d'Azur, INSERM U1081 CNRS UMR7284, Institute for Research on Cancer and Aging, Nice (IRCAN), Faculty of Medicine, France.,Department of Medical Genetics, Archet 2 Hospital, CHU of Nice, France
| | - Annamaria Biroccio
- Oncogenomic and Epigenetic Unit, Regina Elena National Cancer Institute, Via Elio Chianesi 53, Rome 00144, Italy
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71
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Transcription regulation of CDKN1A (p21/CIP1/WAF1) by TRF2 is epigenetically controlled through the REST repressor complex. Sci Rep 2017; 7:11541. [PMID: 28912501 PMCID: PMC5599563 DOI: 10.1038/s41598-017-11177-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/20/2017] [Indexed: 12/13/2022] Open
Abstract
We observed extra-telomeric binding of the telomere repeat binding factor TRF2 within the promoter of the cyclin-dependent kinase CDKNIA (p21/CIP1/WAF1). This result in TRF2 induced transcription repression of p21. Interestingly, p21 repression was through engagement of the REST-coREST-LSD1-repressor complex and altered histone marks at the p21 promoter in a TRF2-dependent fashion. Furthermore, mutational analysis shows p21 repression requires interaction of TRF2 with a p21 promoter G-quadruplex. Physiologically, TRF2-mediated p21 repression attenuated drug-induced activation of cellular DNA damage response by evading G2/M arrest in cancer cells. Together these reveal for the first time role of TRF2 in REST- repressor complex mediated transcription repression.
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72
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Expression of miR-23a induces telomere shortening and is associated with poor clinical outcomes in patients with coronary artery disease. Clin Sci (Lond) 2017. [PMID: 28646123 DOI: 10.1042/cs20170242] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Telomeric repeat binding factor (TRF) 2 (TRF2) plays an important role in telomere maintenance. miR-23a may directly inhibit TRF2 expression, thereby, inducing telomere shortening and cellular senescence. The present study aimed to determine whether miR-23a and TRF2 are expressed in patients with coronary artery disease (CAD), and whether pitavastatin might affect these levels. The present study included 104 patients with CAD and 50 controls. Patients with CAD were randomly divided into two subgroups (a moderate lipid lowering therapy (LLT) group and an aggressive LLT group). Peripheral blood mononuclear cells (PBMCs) were taken from patients with CAD and from controls at baseline and after 12 months. Levels of miR-23a were higher in the CAD group than in the controls. Levels of TRF2 protein were lower in the CAD group than in the controls. Our randomized clinical study showed that aggressive LLT decreased miR-23a and increased TRF2 levels, whereas moderate LLT generated no change in these levels. Our transfected cell model showed that miR-23a controlled TRF2 expression. After a mean follow-up of 339 days, cardiovascular events were associated with high miR-23a, low TRF2 or low relative telomere length. Multivariate analysis showed that levels of miR-23a (RR: 4.9, 95% CI: 1.9-14.3) were a strong predictor of cardiovascular events after adjustment for baseline characteristics. In conclusion, elevated levels of miR-23a play an important role in coronary atherosclerosis via down-regulated TRF2, and may provide important prognostic information in patients with CAD. Additionally, aggressive LLT may prevent telomere erosion via down-regulated miR-23a.
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73
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Yalçin Z, Selenz C, Jacobs JJL. Ubiquitination and SUMOylation in Telomere Maintenance and Dysfunction. Front Genet 2017; 8:67. [PMID: 28588610 PMCID: PMC5440461 DOI: 10.3389/fgene.2017.00067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 05/10/2017] [Indexed: 12/14/2022] Open
Abstract
Telomeres are essential nucleoprotein structures at linear chromosomes that maintain genome integrity by protecting chromosome ends from being recognized and processed as damaged DNA. In addition, they limit the cell’s proliferative capacity, as progressive loss of telomeric DNA during successive rounds of cell division eventually causes a state of telomere dysfunction that prevents further cell division. When telomeres become critically short, the cell elicits a DNA damage response resulting in senescence, apoptosis or genomic instability, thereby impacting on aging and tumorigenesis. Over the past years substantial progress has been made in understanding the role of post-translational modifications in telomere-related processes, including telomere maintenance, replication and dysfunction. This review will focus on recent findings that establish an essential role for ubiquitination and SUMOylation at telomeres.
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Affiliation(s)
- Zeliha Yalçin
- Department of Molecular Oncology, Netherlands Cancer InstituteAmsterdam, Netherlands
| | - Carolin Selenz
- Department of Molecular Oncology, Netherlands Cancer InstituteAmsterdam, Netherlands
| | - Jacqueline J L Jacobs
- Department of Molecular Oncology, Netherlands Cancer InstituteAmsterdam, Netherlands
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74
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Chandrasekaran A, Idelchik MDPS, Melendez JA. Redox control of senescence and age-related disease. Redox Biol 2017; 11:91-102. [PMID: 27889642 PMCID: PMC5126126 DOI: 10.1016/j.redox.2016.11.005] [Citation(s) in RCA: 208] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 11/10/2016] [Indexed: 12/17/2022] Open
Abstract
The signaling networks that drive the aging process, associated functional deterioration, and pathologies has captured the scientific community's attention for decades. While many theories exist to explain the aging process, the production of reactive oxygen species (ROS) provides a signaling link between engagement of cellular senescence and several age-associated pathologies. Cellular senescence has evolved to restrict tumor progression but the accompanying senescence-associated secretory phenotype (SASP) promotes pathogenic pathways. Here, we review known biological theories of aging and how ROS mechanistically control senescence and the aging process. We also describe the redox-regulated signaling networks controlling the SASP and its important role in driving age-related diseases. Finally, we discuss progress in designing therapeutic strategies that manipulate the cellular redox environment to restrict age-associated pathology.
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Affiliation(s)
- Akshaya Chandrasekaran
- SUNY Polytechnic Institute, Colleges of Nanoscale Science and Engineering, 257 Fuller Road, Albany, NY 12203, USA
| | | | - J Andrés Melendez
- SUNY Polytechnic Institute, Colleges of Nanoscale Science and Engineering, 257 Fuller Road, Albany, NY 12203, USA.
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75
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Vancevska A, Douglass KM, Pfeiffer V, Manley S, Lingner J. The telomeric DNA damage response occurs in the absence of chromatin decompaction. Genes Dev 2017; 31:567-577. [PMID: 28381410 PMCID: PMC5393052 DOI: 10.1101/gad.294082.116] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 02/14/2017] [Indexed: 12/22/2022]
Abstract
Telomeres are specialized nucleoprotein structures that protect chromosome ends from DNA damage response (DDR) and DNA rearrangements. The telomeric shelterin protein TRF2 suppresses the DDR, and this function has been attributed to its abilities to trigger t-loop formation or prevent massive decompaction and loss of density of telomeric chromatin. Here, we applied stochastic optical reconstruction microscopy (STORM) to measure the sizes and shapes of functional human telomeres of different lengths and dysfunctional telomeres that elicit a DDR. Telomeres have an ovoid appearance with considerable plasticity in shape. Examination of many telomeres demonstrated that depletion of TRF2, TRF1, or both affected the sizes of only a small subset of telomeres. Costaining of telomeres with DDR markers further revealed that the majority of DDR signaling telomeres retained a normal size. Thus, DDR signaling at telomeres does not require decompaction. We propose that telomeres are monitored by the DDR machinery in the absence of telomere expansion and that the DDR is triggered by changes at the molecular level in structure and protein composition.
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Affiliation(s)
- Aleksandra Vancevska
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Kyle M Douglass
- Institute of Physics, Laboratory of Experimental Biophysics, EPFL, 1015 Lausanne, Switzerland
| | - Verena Pfeiffer
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Suliana Manley
- Institute of Physics, Laboratory of Experimental Biophysics, EPFL, 1015 Lausanne, Switzerland
| | - Joachim Lingner
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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76
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Berardinelli F, Coluzzi E, Sgura A, Antoccia A. Targeting telomerase and telomeres to enhance ionizing radiation effects in in vitro and in vivo cancer models. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 773:204-219. [PMID: 28927529 DOI: 10.1016/j.mrrev.2017.02.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 02/13/2017] [Accepted: 02/14/2017] [Indexed: 01/05/2023]
Abstract
One of the hallmarks of cancer consists in the ability of tumor cells to divide indefinitely, and to maintain stable telomere lengths throughout the activation of specific telomere maintenance mechanisms (TMM). Therefore in the last fifteen years, researchers proposed to target telomerase or telomeric structure in order to block limitless replicative potential of cancer cells providing a fascinating strategy for a broad-spectrum cancer therapy. In the present review, we report in vitro and in vivo evidence regarding the use of chemical agents targeting both telomerase or telomere structure and showing promising antitumor effects when used in combination with ionizing radiation (IR). RNA interference, antisense oligonucleotides (e.g., GRN163L), non-nucleoside inhibitors (e.g., BIBR1532) and nucleoside analogs (e.g., AZT) represent some of the most potent strategies to inhibit telomerase activity used in combination with IR. Furthermore, radiosensitizing effects were demonstrated also for agents acting directly on the telomeric structure such as G4-ligands (e.g., RHPS4 and Telomestatin) or telomeric-oligos (T-oligos). To date, some of these compounds are under clinical evaluation (e.g., GRN163L and KML001). Advantages of Telomere/Telomerase Targeting Compounds (T/TTCs) coupled with radiotherapy may be relevant in the treatment of radioresistant tumors and in the development of new optimized treatment plans with reduced dose adsorbed by patients and consequent attenuation of short- end long-term side effects. Pros and cons of possible future applications in cancer therapy based on the combination of T/TCCs and radiation treatment are discussed.
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Affiliation(s)
- F Berardinelli
- Dipartimento di Scienze, Università Roma Tre, Rome Italy; Istituto Nazionale di Fisica Nucleare, INFN, Sezione di Roma Tre, Rome, Italy.
| | - E Coluzzi
- Dipartimento di Scienze, Università Roma Tre, Rome Italy
| | - A Sgura
- Dipartimento di Scienze, Università Roma Tre, Rome Italy; Istituto Nazionale di Fisica Nucleare, INFN, Sezione di Roma Tre, Rome, Italy
| | - A Antoccia
- Dipartimento di Scienze, Università Roma Tre, Rome Italy; Istituto Nazionale di Fisica Nucleare, INFN, Sezione di Roma Tre, Rome, Italy
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77
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Lee WP, Lan KH, Li CP, Chao Y, Hou MC, Lin HC, Lee SD. The telomere-binding protein TRF2 is required for metronomic therapeutic effects of gemcitabine and capecitabine. Biochim Biophys Acta Mol Basis Dis 2017; 1863:917-928. [PMID: 28088627 DOI: 10.1016/j.bbadis.2017.01.008] [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: 09/29/2016] [Revised: 01/02/2017] [Accepted: 01/10/2017] [Indexed: 12/18/2022]
Abstract
Gemcitabine and capecitabine are two effective anticancer agents against solid tumors. The pharmacological mechanisms have been known as incorporation into DNA and thereby inhibition of DNA synthesis. When used as metronomic chemotherapy, they may inhibit angiogenesis and induce immunity. In our previous study, we showed that low-dose gemcitabine caused telomere shortening by stabilizing TRF2 that was required for XPF-dependent telomere loss. In this report, we established a SKOV3.ip1 ascites cell model. Tumor-bearing mice were treated with low-dose gemcitabine (GEM) or capecitabine (CAP). Both GEM and CAP caused telomere shortening and increased expression of TRF2 with improved ascites in nude mice and decreased in vitro clonogenic activity. TRF2 knockdown altered telomeres to a shortened but new status that may evade XPF-dependent telomere loss and conferred resistance of SKOV3.ip1 ascites cells to low-dose GEM and CAP. Our study provides a new mechanism of metronomic chemotherapy i.e. TRF2 is required for metronomic therapeutic effects of gemcitabine and capecitabine.
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Affiliation(s)
- Wei-Ping Lee
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan; Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.
| | - Keng-Hsin Lan
- Department of Medicine Division of Gastroenterology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chung-Pin Li
- Department of Medicine Division of Gastroenterology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Yee Chao
- Cancer Center, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Ming-Chih Hou
- Department of Medicine Division of Gastroenterology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Han-Chieh Lin
- Department of Medicine Division of Gastroenterology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Shou-Dong Lee
- Department of Medicine Division of Gastroenterology, Taipei Veterans General Hospital, Taipei, Taiwan
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78
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Locatelli M, Curigliano G. Targeting Genome Instability and DNA Repair. Breast Cancer 2017. [DOI: 10.1007/978-3-319-48848-6_68] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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79
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Graziano S, Gonzalo S. Mechanisms of oncogene-induced genomic instability. Biophys Chem 2016; 225:49-57. [PMID: 28073589 DOI: 10.1016/j.bpc.2016.11.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 11/17/2016] [Accepted: 11/18/2016] [Indexed: 01/08/2023]
Abstract
Activating mutations in oncogenes promote uncontrolled proliferation and malignant transformation. Approximately 30% of human cancers carry mutations in the RAS oncogene. Paradoxically, expression of mutant constitutively active Ras protein in primary human cells results in a premature proliferation arrest known as oncogene-induced senescence (OIS). This is more commonly observed in human pre-neoplasia than in neoplastic lesions, and is considered a tumor suppressor mechanism. Senescent cells are still metabolically active but in a status of cell cycle arrest characterized by specific morphological and physiological features that distinguish them from both proliferating cells, and cells growth-arrested by other means. Although the molecular mechanisms by which OIS is established are not totally understood, the current view is that OIS in human cells is tightly linked to persistent activation of the DNA damage response (DDR) pathway, as a consequence of replication stress. Here we will highlight recent advances in our understanding of molecular mechanisms leading to hyper-replication stress in response to oncogene activation, and of the crosstalk between replication stress and persistent activation of the DDR. We will also discuss new evidence for DNA repair deficiencies during OIS, which might increase the genomic instability that drives senescence bypass and malignant transformation.
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Affiliation(s)
- Simona Graziano
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Susana Gonzalo
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA.
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80
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Differences in the recruitment of DNA repair proteins at subtelomeric and interstitial I-SceI endonuclease-induced DNA double-strand breaks. DNA Repair (Amst) 2016; 49:1-8. [PMID: 27842255 DOI: 10.1016/j.dnarep.2016.10.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/21/2016] [Accepted: 10/26/2016] [Indexed: 12/28/2022]
Abstract
Telomeres are nucleoprotein structures that are required to protect chromosome ends. Dysfunctional telomeres are recognized as DNA double-strand breaks (DSBs), and elicit the activation of a DNA damage response (DDR). We have previously reported that DSBs near telomeres are poorly repaired, resulting in a high frequency of large deletions and gross chromosome rearrangements (GCRs). Our previous genetic studies have demonstrated that this sensitivity of telomeric regions to DSBs is a result of excessive processing. In the current study, we have further investigated the sensitivity of telomeric regions to DSBs through the analysis of repair proteins associated with DSBs at interstitial and telomeric sites. Following the inducible expression of I-SceI endonuclease, chromatin immunoprecipitation (ChIP) and real-time quantitative PCR were used to compare the recruitment of repair proteins at I-SceI-induced DSBs at interstitial and subtelomeric sites. We observed that proteins that are specifically associated with processing of DSBs during homologous recombination repair, RAD51, BRCA1, and CtIP, are present at a much greater abundance at subtelomeric DSBs. In contrast, Ku70, which is specifically involved in classical nonhomologous end joining, showed no difference at interstitial and subtelomeric DSBs. Importantly, ATM was lower in abundance at subtelomeric DSBs, while ATR was in greater abundance at subtelomeric DSBs, consistent with the accumulation of processed DSBs near telomeres, since processing is accompanied by a transition from ATM to ATR binding. Combined, our results suggest that excessive processing is responsible for the increased frequency of large deletions and GCRs at DSBs near telomeres.
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81
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Grammatikakis I, Zhang P, Mattson MP, Gorospe M. The long and the short of TRF2 in neurogenesis. Cell Cycle 2016; 15:3026-3032. [PMID: 27565210 DOI: 10.1080/15384101.2016.1222339] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Gene expression patterns change dramatically during neuronal development. Proliferating cells, including neural stem cells (NSCs), express telomere repeat-binding factor 2 (TRF2), a nuclear protein that associates with telomeric proteins, DNA, and RNA telomeres. In NSCs TRF2 also binds to the transcription regulator REST to facilitate repression of numerous neuron-specific genes, thereby keeping the NSCs in a self-renewing state. Upon neuronal differentiation, TRF2 levels decline, REST-regulated neuronal genes are derepressed, and a short isoform of TRF2 arises (TRF2-S) which localizes in the cytoplasm, associates with different subsets of proteins and transcripts, and mobilizes axonal G-rich mRNAs. We recently identified two RNA-binding proteins, HNRNPH1 and H2 (referred to jointly as HNRNPH due to their high homology), which mediate the alternative splicing of an exon required for the expression of full-length TRF2. As HNRNPH levels decline during neurogenesis, TRF2 abundance decreases and TRF2-S accumulates. Here, we discuss the shared and unique functions of TRF2 and TRF2-S, the distinct subcellular compartment in which each isoform resides, the subsets of proteins and nucleic acids with which each interacts, and the functional consequences of these ribonucleoprotein interactions. This paradigm illustrates the dynamic mechanisms through which splicing regulation by factors like HNRNPH enable distinct protein functions as cells adapt to developmental programs such as neurogenesis.
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Affiliation(s)
- Ioannis Grammatikakis
- a Laboratory of Genetics, National Institute on Aging, National Institutes of Health , Baltimore , MD , USA
| | - Peisu Zhang
- b Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health , Baltimore , MD , USA
| | - Mark P Mattson
- b Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health , Baltimore , MD , USA
| | - Myriam Gorospe
- a Laboratory of Genetics, National Institute on Aging, National Institutes of Health , Baltimore , MD , USA
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82
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Lieberman PM. Retrotransposon-derived p53 binding sites enhance telomere maintenance and genome protection. Bioessays 2016; 38:943-9. [PMID: 27539745 DOI: 10.1002/bies.201600078] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Tumor suppressor protein 53 (p53) plays a central role in the control of genome stability, acting primarily through the transcriptional activation of stress-response genes. However, many p53 binding sites are located at genomic locations with no obvious regulatory-link to known stress-response genes. We recently discovered p53 binding sites within retrotransposon-derived elements in human and mouse subtelomeres. These retrotransposon-derived p53 binding sites protected chromosome ends through transcription activation of telomere repeat RNA, as well as through the direct modification of local chromatin structure in response to DNA damage. Based on these findings, I hypothesize that a class of p53 binding sites, including the retrotransposon-derived p53-sites found in subtlomeres, provide a primary function in genome stability by mounting a direct and local protective chromatin-response to DNA damage. I speculate that retrotransposon-derived p53 binding sites share features with telomere-repeats through an evolutionary drive to monitor and maintain genome integrity.
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83
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Bandaria JN, Qin P, Berk V, Chu S, Yildiz A. Shelterin Protects Chromosome Ends by Compacting Telomeric Chromatin. Cell 2016; 164:735-46. [PMID: 26871633 DOI: 10.1016/j.cell.2016.01.036] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/28/2015] [Accepted: 01/22/2016] [Indexed: 12/12/2022]
Abstract
Telomeres, repetitive DNA sequences at chromosome ends, are shielded against the DNA damage response (DDR) by the shelterin complex. To understand how shelterin protects telomere ends, we investigated the structural organization of telomeric chromatin in human cells using super-resolution microscopy. We found that telomeres form compact globular structures through a complex network of interactions between shelterin subunits and telomeric DNA, but not by DNA methylation, histone deacetylation, or histone trimethylation at telomeres and subtelomeric regions. Mutations that abrogate shelterin assembly or removal of individual subunits from telomeres cause up to a 10-fold increase in telomere volume. Decompacted telomeres accumulate DDR signals and become more accessible to telomere-associated proteins. Recompaction of telomeric chromatin using an orthogonal method displaces DDR signals from telomeres. These results reveal the chromatin remodeling activity of shelterin and demonstrate that shelterin-mediated compaction of telomeric chromatin provides robust protection of chromosome ends against the DDR machinery.
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Affiliation(s)
- Jigar N Bandaria
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Peiwu Qin
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Veysel Berk
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Steven Chu
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Ahmet Yildiz
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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84
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Wang Z, Lieberman PM. The crosstalk of telomere dysfunction and inflammation through cell-free TERRA containing exosomes. RNA Biol 2016; 13:690-5. [PMID: 27351774 DOI: 10.1080/15476286.2016.1203503] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Telomeric repeats-containing RNA (TERRA) are telomere-derived non-coding RNAs that contribute to telomere function in protecting chromosome ends. We recently identified a cell-free form of TERRA (cfTERRA) enriched in extracellular exosomes. These cfTERRA-containing exosomes stimulate inflammatory cytokines when incubated with immune responsive cells. Here, we report that cfTERRA levels were increased in exosomes during telomere dysfunction induced by the expression of the dominant negative TRF2. The exosomes from these damaged cells also enriched with DNA damage marker γH2AX and fragmented telomere repeat DNA. Purified cfTERRA stimulated inflammatory cytokines, but the intact membrane-associated nucleoprotein complexes produced a more robust cytokine activation. Therefore, we propose cfTERRA-containing exosomes transport a telomere-associated molecular pattern (TAMP) and telomere-specific alarmin from dysfunctional telomeres to the extracellular environment to elicit an inflammatory response. Since cfTERRA can be readily detected in human serum it may provide a useful biomarker for the detection of telomere dysfunction in the early stage of cancers and aging-associated inflammatory disease.
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Affiliation(s)
- Zhuo Wang
- a The Wistar Institute , Philadelphia , PA , USA.,b University of the Sciences in Philadelphia , Philadelphia , PA , USA
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85
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Stop pulling my strings - what telomeres taught us about the DNA damage response. Nat Rev Mol Cell Biol 2016; 17:364-78. [PMID: 27165790 DOI: 10.1038/nrm.2016.43] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mammalian cells have evolved specialized mechanisms to sense and repair double-strand breaks (DSBs) to maintain genomic stability. However, in certain cases, the activity of these pathways can lead to aberrant DNA repair, genomic instability and tumorigenesis. One such case is DNA repair at the natural ends of linear chromosomes, known as telomeres, which can lead to chromosome-end fusions. Here, we review data obtained over the past decade and discuss the mechanisms that protect mammalian chromosome ends from the DNA damage response. We also discuss how telomere research has helped to uncover key steps in DSB repair. Last, we summarize how dysfunctional telomeres and the ensuing genomic instability drive the progression of cancer.
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86
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Benhamou Y, Picco V, Pagès G. The telomere proteins in tumorigenesis and clinical outcomes of oral squamous cell carcinoma. Oral Oncol 2016; 57:46-53. [PMID: 27208844 DOI: 10.1016/j.oraloncology.2016.04.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/29/2016] [Accepted: 04/12/2016] [Indexed: 12/16/2022]
Abstract
The "Hallmarks of Cancer" describe the ways by which cancer cells bypass homeostasis. Escape from replicative senescence is one of the earliest features of cancer cells. Maintenance of the telomeres through reactivation of telomerase was initially associated with replicative immortality in various cancers. The shelterin complex, a telomeric hexaprotein association, plays a key role in telomere maintenance and in the hallmarks of cancer. Some shelterin proteins are overexpressed in diverse cancers and can promote tumorigenesis in animal models. Shelterin can also have an impact on tumor size, tumor growth and resistance to treatment. Studies into the expression level of shelterin in oral squamous cell carcinoma (OSCC) report contradictory results. Moreover, the exact role of these proteins in OSCC tumorigenesis remains uncertain. In this review, we examined the data linking telomeres and hallmarks of OSCC. Furthermore, we examined the literature concerning telomeres and the clinical outcome of OSCC. Finally, we propose a model encompassing the role of shelterin proteins in oral tumorigenesis and treatment outcome.
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Affiliation(s)
- Y Benhamou
- University of Nice Sophia Antipolis, Institute for Research on Cancer and Aging of Nice CNRS UMR 7284/INSERM U 1081, France; University of Nice Sophia Antipolis, Nice University Hospital, Odontology Department, Nice, France
| | - V Picco
- Centre Scientifique de Monaco, Biomedical Department, 8 Quai Antoine Ier, MC-98000 Monaco, Monaco
| | - G Pagès
- University of Nice Sophia Antipolis, Institute for Research on Cancer and Aging of Nice CNRS UMR 7284/INSERM U 1081, France
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87
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Zhang J, Rane G, Dai X, Shanmugam MK, Arfuso F, Samy RP, Lai MKP, Kappei D, Kumar AP, Sethi G. Ageing and the telomere connection: An intimate relationship with inflammation. Ageing Res Rev 2016; 25:55-69. [PMID: 26616852 DOI: 10.1016/j.arr.2015.11.006] [Citation(s) in RCA: 251] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 11/16/2015] [Accepted: 11/19/2015] [Indexed: 12/19/2022]
Abstract
Telomeres are the heterochromatic repeat regions at the ends of eukaryotic chromosomes, whose length is considered to be a determinant of biological ageing. Normal ageing itself is associated with telomere shortening. Here, critically short telomeres trigger senescence and eventually cell death. This shortening rate may be further increased by inflammation and oxidative stress and thus affect the ageing process. Apart from shortened or dysfunctional telomeres, cells undergoing senescence are also associated with hyperactivity of the transcription factor NF-κB and overexpression of inflammatory cytokines such as TNF-α, IL-6, and IFN-γ in circulating macrophages. Interestingly, telomerase, a reverse transcriptase that elongates telomeres, is involved in modulating NF-κB activity. Furthermore, inflammation and oxidative stress are implicated as pre-disease mechanisms for chronic diseases of ageing such as neurodegenerative diseases, cardiovascular disease, and cancer. To date, inflammation and telomere shortening have mostly been studied individually in terms of ageing and the associated disease phenotype. However, the interdependent nature of the two demands a more synergistic approach in understanding the ageing process itself and for developing new therapeutic approaches. In this review, we aim to summarize the intricate association between the various inflammatory molecules and telomeres that together contribute to the ageing process and related diseases.
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88
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Abstract
Loss of function or mutation of the ataxia-telangiectasia mutated gene product (ATM) results in inherited genetic disorders characterized by neurodegeneration, immunodeficiency, and cancer. Ataxia-telangiectasia mutated (ATM) gene product belongs to the PI3K-like protein kinase (PIKKs) family and is functionally implicated in mitogenic signal transduction, chromosome condensation, meiotic recombination, cell-cycle control, and telomere maintenance. The ATM protein kinase is primarily activated in response to DNA double strand breaks (DSBs), the most deleterious form of DNA damage produced by ionizing radiation (IR) or radiomimetic drugs. It is detected at DNA damage sites, where ATM autophosphorylation causes dissociation of the inactive homodimeric form to the activated monomeric form. Interestingly, heat shock can activate ATM independent of the presence of DNA strand breaks. ATM is an integral part of the sensory machinery that detects DSBs during meiosis, mitosis, or DNA breaks mediated by free radicals. These DNA lesions can trigger higher order chromatin reorganization fuelled by posttranslational modifications of histones and histone binding proteins. Our group, and others, have shown that ATM activation is tightly regulated by chromatin modifications. This review summarizes the multiple approaches used to discern the role of ATM and other associated proteins in chromatin modification in response to DNA damage.
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89
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Ferguson LR, Chen H, Collins AR, Connell M, Damia G, Dasgupta S, Malhotra M, Meeker AK, Amedei A, Amin A, Ashraf SS, Aquilano K, Azmi AS, Bhakta D, Bilsland A, Boosani CS, Chen S, Ciriolo MR, Fujii H, Guha G, Halicka D, Helferich WG, Keith WN, Mohammed SI, Niccolai E, Yang X, Honoki K, Parslow VR, Prakash S, Rezazadeh S, Shackelford RE, Sidransky D, Tran PT, Yang ES, Maxwell CA. Genomic instability in human cancer: Molecular insights and opportunities for therapeutic attack and prevention through diet and nutrition. Semin Cancer Biol 2015; 35 Suppl:S5-S24. [PMID: 25869442 PMCID: PMC4600419 DOI: 10.1016/j.semcancer.2015.03.005] [Citation(s) in RCA: 195] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 03/08/2015] [Accepted: 03/13/2015] [Indexed: 02/06/2023]
Abstract
Genomic instability can initiate cancer, augment progression, and influence the overall prognosis of the affected patient. Genomic instability arises from many different pathways, such as telomere damage, centrosome amplification, epigenetic modifications, and DNA damage from endogenous and exogenous sources, and can be perpetuating, or limiting, through the induction of mutations or aneuploidy, both enabling and catastrophic. Many cancer treatments induce DNA damage to impair cell division on a global scale but it is accepted that personalized treatments, those that are tailored to the particular patient and type of cancer, must also be developed. In this review, we detail the mechanisms from which genomic instability arises and can lead to cancer, as well as treatments and measures that prevent genomic instability or take advantage of the cellular defects caused by genomic instability. In particular, we identify and discuss five priority targets against genomic instability: (1) prevention of DNA damage; (2) enhancement of DNA repair; (3) targeting deficient DNA repair; (4) impairing centrosome clustering; and, (5) inhibition of telomerase activity. Moreover, we highlight vitamin D and B, selenium, carotenoids, PARP inhibitors, resveratrol, and isothiocyanates as priority approaches against genomic instability. The prioritized target sites and approaches were cross validated to identify potential synergistic effects on a number of important areas of cancer biology.
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Affiliation(s)
| | - Helen Chen
- Department of Pediatrics, University of British Columbia, Michael Cuccione Childhood Cancer Research Program, Child and Family Research Institute, Vancouver, Canada
| | - Andrew R Collins
- Department of Nutrition, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Marisa Connell
- Department of Pediatrics, University of British Columbia, Michael Cuccione Childhood Cancer Research Program, Child and Family Research Institute, Vancouver, Canada
| | - Giovanna Damia
- Department of Oncology, Instituti di Ricovero e Cura a Carattere Scientifico-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Santanu Dasgupta
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, United States
| | | | - Alan K Meeker
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Amedeo Amedei
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Amr Amin
- Department of Biology, College of Science, United Arab Emirates University, Al Ain, United Arab Emirates; Faculty of Science, Cairo University, Cairo, Egypt
| | - S Salman Ashraf
- Department of Chemistry, College of Science, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Katia Aquilano
- Department of Biology, Università di Roma Tor Vergata, Rome, Italy
| | - Asfar S Azmi
- Department of Biology, University of Rochester, Rochester, United States
| | - Dipita Bhakta
- School of Chemical and BioTechnology, SASTRA University, Thanjavur, Tamil Nadu, India
| | - Alan Bilsland
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Chandra S Boosani
- Department of BioMedical Sciences, Creighton University, Omaha, NE, United States
| | - Sophie Chen
- Department of Research & Development, Ovarian and Prostate Cancer Research Trust Laboratory, Guildford, Surrey, United Kingdom
| | | | - Hiromasa Fujii
- Department of Orthopaedic Surgery, Nara Medical University, Kashihara, Nara, Japan
| | - Gunjan Guha
- School of Chemical and BioTechnology, SASTRA University, Thanjavur, Tamil Nadu, India
| | | | - William G Helferich
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - W Nicol Keith
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Sulma I Mohammed
- Department of Comparative Pathobiology and Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN, United States
| | - Elena Niccolai
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Xujuan Yang
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Kanya Honoki
- Department of Orthopaedic Surgery, Nara Medical University, Kashihara, Nara, Japan
| | | | - Satya Prakash
- School of Pharmacy, University College Cork, Cork, Ireland
| | - Sarallah Rezazadeh
- Department of Biology, University of Rochester, Rochester, United States
| | - Rodney E Shackelford
- Department of Pathology, Louisiana State University Health Shreveport, Shreveport, LA, United States
| | - David Sidransky
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Phuoc T Tran
- Departments of Radiation Oncology & Molecular Radiation Sciences, Oncology and Urology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Eddy S Yang
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Christopher A Maxwell
- Department of Pediatrics, University of British Columbia, Michael Cuccione Childhood Cancer Research Program, Child and Family Research Institute, Vancouver, Canada.
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90
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Spontaneous tumor development in bone marrow-rescued DNA-PKcs(3A/3A) mice due to dysfunction of telomere leading strand deprotection. Oncogene 2015; 35:3909-18. [PMID: 26616856 PMCID: PMC4885801 DOI: 10.1038/onc.2015.459] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 10/29/2015] [Accepted: 10/30/2015] [Indexed: 12/16/2022]
Abstract
Phosphorylation of the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) at the Thr2609 cluster is essential for its complete function in DNA repair and tissue stem cell homeostasis. This phenomenon is demonstrated by congenital bone marrow failure occurring in DNA-PKcs3A/3A mutant mice, which require bone marrow transplantation (BMT) to prevent early mortality. Surprisingly, an increased incidence of spontaneous tumors, especially skin cancer, was observed in adult BMT-rescued DNA-PKcs3A/3A mice. Upon further investigation we found that spontaneous γH2AX foci occurred in DNA-PKcs3A/3A skin biopsies and primary keratinocytes and that these foci overlapped with telomeres during mitosis, indicating impairment of telomere replication and maturation. Consistently, we observed significantly elevated frequencies of telomere fusion events in DNA-PKcs3A/3A cells as compared to wild type and DNA-PKcs knockout cells. In addition, a previously identified DNA-PKcs Thr2609Pro mutation, found in breast cancer, also induces a similar impairment of telomere leading end maturation. Taken together, our current analyses indicate that the functional DNA-PKcs T2609 cluster is required to facilitate telomere leading strand maturation and prevention of genomic instability and cancer development.
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91
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Wang J, Uryga AK, Reinhold J, Figg N, Baker L, Finigan A, Gray K, Kumar S, Clarke M, Bennett M. Vascular Smooth Muscle Cell Senescence Promotes Atherosclerosis and Features of Plaque Vulnerability. Circulation 2015; 132:1909-19. [DOI: 10.1161/circulationaha.115.016457] [Citation(s) in RCA: 187] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 09/17/2015] [Indexed: 12/28/2022]
Abstract
Background—
Although vascular smooth muscle cell (VSMC) proliferation is implicated in atherogenesis, VSMCs in advanced plaques and cultured from plaques show evidence of VSMC senescence and DNA damage. In particular, plaque VSMCs show shortening of telomeres, which can directly induce senescence. Senescence can have multiple effects on plaque development and morphology; however, the consequences of VSMC senescence or the mechanisms underlying VSMC senescence in atherosclerosis are mostly unknown.
Methods and Results—
We examined the expression of proteins that protect telomeres in VSMCs derived from human plaques and normal vessels. Plaque VSMCs showed reduced expression and telomere binding of telomeric repeat-binding factor-2 (TRF2), associated with increased DNA damage. TRF2 expression was regulated by p53-dependent degradation of the TRF2 protein. To examine the functional consequences of loss of TRF2, we expressed TRF2 or a TRF2 functional mutant (T188A) as either gain- or loss-of-function studies in vitro and in apolipoprotein E
–/–
mice. TRF2 overexpression bypassed senescence, reduced DNA damage, and accelerated DNA repair, whereas TRF2
188A
showed opposite effects. Transgenic mice expressing VSMC-specific TRF2
T188A
showed increased atherosclerosis and necrotic core formation in vivo, whereas VSMC-specific TRF2 increased the relative fibrous cap and decreased necrotic core areas. TRF2 protected against atherosclerosis independent of secretion of senescence-associated cytokines.
Conclusions—
We conclude that plaque VSMC senescence in atherosclerosis is associated with loss of TRF2. VSMC senes cence promotes both atherosclerosis and features of plaque vulnerability, identifying prevention of senescence as a potential target for intervention.
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Affiliation(s)
- Julie Wang
- From Division of Cardiovascular Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Anna K. Uryga
- From Division of Cardiovascular Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Johannes Reinhold
- From Division of Cardiovascular Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Nichola Figg
- From Division of Cardiovascular Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Lauren Baker
- From Division of Cardiovascular Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Alison Finigan
- From Division of Cardiovascular Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Kelly Gray
- From Division of Cardiovascular Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Sheetal Kumar
- From Division of Cardiovascular Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Murray Clarke
- From Division of Cardiovascular Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Martin Bennett
- From Division of Cardiovascular Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, United Kingdom
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92
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Tong AS, Stern JL, Sfeir A, Kartawinata M, de Lange T, Zhu XD, Bryan TM. ATM and ATR Signaling Regulate the Recruitment of Human Telomerase to Telomeres. Cell Rep 2015; 13:1633-46. [PMID: 26586433 DOI: 10.1016/j.celrep.2015.10.041] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 09/14/2015] [Accepted: 10/16/2015] [Indexed: 01/06/2023] Open
Abstract
The yeast homologs of the ATM and ATR DNA damage response kinases play key roles in telomerase-mediated telomere maintenance, but the role of ATM/ATR in the mammalian telomerase pathway has been less clear. Here, we demonstrate the requirement for ATM and ATR in the localization of telomerase to telomeres and telomere elongation in immortal human cells. Stalled replication forks increased telomerase recruitment in an ATR-dependent manner. Furthermore, increased telomerase recruitment was observed upon phosphorylation of the shelterin component TRF1 at an ATM/ATR target site (S367). This phosphorylation leads to loss of TRF1 from telomeres and may therefore increase replication fork stalling. ATM and ATR depletion reduced assembly of the telomerase complex, and ATM was required for telomere elongation in cells expressing POT1ΔOB, an allele of POT1 that disrupts telomere-length homeostasis. These data establish that human telomerase recruitment and telomere elongation are modulated by DNA-damage-transducing kinases.
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Affiliation(s)
- Adrian S Tong
- Cell Biology Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
| | - J Lewis Stern
- Cell Biology Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
| | - Agnel Sfeir
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY 10065, USA
| | - Melissa Kartawinata
- Cell Biology Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY 10065, USA
| | - Xu-Dong Zhu
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Tracy M Bryan
- Cell Biology Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia.
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93
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Saquilabon Cruz GM, Kong X, Silva BA, Khatibzadeh N, Thai R, Berns MW, Yokomori K. Femtosecond near-infrared laser microirradiation reveals a crucial role for PARP signaling on factor assemblies at DNA damage sites. Nucleic Acids Res 2015; 44:e27. [PMID: 26424850 PMCID: PMC4756852 DOI: 10.1093/nar/gkv976] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 09/18/2015] [Indexed: 01/04/2023] Open
Abstract
Laser microirradiation is a powerful tool for real-time single-cell analysis of the DNA damage response (DDR). It is often found, however, that factor recruitment or modification profiles vary depending on the laser system employed. This is likely due to an incomplete understanding of how laser conditions/dosages affect the amounts and types of damage and the DDR. We compared different irradiation conditions using a femtosecond near-infrared laser and found distinct damage site recruitment thresholds for 53BP1 and TRF2 correlating with the dose-dependent increase of strand breaks and damage complexity. Low input-power microirradiation that induces relatively simple strand breaks led to robust recruitment of 53BP1 but not TRF2. In contrast, increased strand breaks with complex damage including crosslinking and base damage generated by high input-power microirradiation resulted in TRF2 recruitment to damage sites with no 53BP1 clustering. We found that poly(ADP-ribose) polymerase (PARP) activation distinguishes between the two damage states and that PARP activation is essential for rapid TRF2 recruitment while suppressing 53BP1 accumulation at damage sites. Thus, our results reveal that careful titration of laser irradiation conditions allows induction of varying amounts and complexities of DNA damage that are gauged by differential PARP activation regulating protein assembly at the damage site.
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Affiliation(s)
- Gladys Mae Saquilabon Cruz
- Beckman Laser Institute and Medical Clinic, University of California, Irvine, 1002 Health Sciences Road East, Irvine, CA 92612, USA
| | - Xiangduo Kong
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700, USA
| | - Bárbara Alcaraz Silva
- Beckman Laser Institute and Medical Clinic, University of California, Irvine, 1002 Health Sciences Road East, Irvine, CA 92612, USA Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, CA 92617, USA
| | - Nima Khatibzadeh
- Beckman Laser Institute and Medical Clinic, University of California, Irvine, 1002 Health Sciences Road East, Irvine, CA 92612, USA
| | - Ryan Thai
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700, USA
| | - Michael W Berns
- Beckman Laser Institute and Medical Clinic, University of California, Irvine, 1002 Health Sciences Road East, Irvine, CA 92612, USA Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, CA 92617, USA Department of Biomedical Engineering and Surgery, University of California, Irvine, CA 92617, USA
| | - Kyoko Yokomori
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA 92697-1700, USA
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94
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Abstract
RecQ helicases are a family of highly conserved proteins that maintain genomic stability through their important roles in replication restart mechanisms. Cellular phenotypes of RECQ1 deficiency are indicative of aberrant repair of stalled replication forks, but the molecular functions of RECQ1, the most abundant of the five known human RecQ homologues, have remained poorly understood. We show that RECQ1 associates with FEN-1 (flap endonuclease-1) in nuclear extracts and exhibits direct protein interaction in vitro. Recombinant RECQ1 significantly stimulated FEN-1 endonucleolytic cleavage of 5'-flap DNA substrates containing non-telomeric or telomeric repeat sequence. RECQ1 and FEN-1 were constitutively present at telomeres and their binding to the telomeric chromatin was enhanced following DNA damage. Telomere residence of FEN-1 was dependent on RECQ1 since depletion of RECQ1 reduced FEN-1 binding to telomeres in unperturbed cycling cells. Our results confirm a conserved collaboration of human RecQ helicases with FEN-1 and suggest both overlapping and specialized roles of RECQ1 in the processing of DNA structure intermediates proposed to arise during replication, repair and recombination.
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95
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Abstract
The ends of linear chromosomes are capped by nucleoprotein structures called telomeres. A dysfunctional telomere may resemble a DNA double-strand break (DSB), which is a severe form of DNA damage. The presence of one DSB is sufficient to drive cell cycle arrest and cell death. Therefore cells have evolved mechanisms to repair DSBs such as homologous recombination (HR). HR-mediated repair of telomeres can lead to genome instability, a hallmark of cancer cells, which is why such repair is normally inhibited. However, some HR-mediated processes are required for proper telomere function. The need for some recombination activities at telomeres but not others necessitates careful and complex regulation, defects in which can lead to catastrophic consequences. Furthermore, some cell types can maintain telomeres via telomerase-independent, recombination-mediated mechanisms. In humans, these mechanisms are called alternative lengthening of telomeres (ALT) and are used in a subset of human cancer cells. In this review, we summarize the different recombination activities occurring at telomeres and discuss how they are regulated. Much of the current knowledge is derived from work using yeast models, which is the focus of this review, but relevant studies in mammals are also included.
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Affiliation(s)
- Clémence Claussin
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Michael Chang
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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96
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Muraki K, Han L, Miller D, Murnane JP. Processing by MRE11 is involved in the sensitivity of subtelomeric regions to DNA double-strand breaks. Nucleic Acids Res 2015. [PMID: 26209132 PMCID: PMC4652756 DOI: 10.1093/nar/gkv714] [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] [Indexed: 12/26/2022] Open
Abstract
The caps on the ends of chromosomes, called telomeres, keep the ends of chromosomes from appearing as DNA double-strand breaks (DSBs) and prevent chromosome fusion. However, subtelomeric regions are sensitive to DSBs, which in normal cells is responsible for ionizing radiation-induced cell senescence and protection against oncogene-induced replication stress, but promotes chromosome instability in cancer cells that lack cell cycle checkpoints. We have previously reported that I-SceI endonuclease-induced DSBs near telomeres in a human cancer cell line are much more likely to generate large deletions and gross chromosome rearrangements (GCRs) than interstitial DSBs, but found no difference in the frequency of I-SceI-induced small deletions at interstitial and subtelomeric DSBs. We now show that inhibition of MRE11 3′–5′ exonuclease activity with Mirin reduces the frequency of large deletions and GCRs at both interstitial and subtelomeric DSBs, but has little effect on the frequency of small deletions. We conclude that large deletions and GCRs are due to excessive processing of DSBs, while most small deletions occur during classical nonhomologous end joining (C-NHEJ). The sensitivity of subtelomeric regions to DSBs is therefore because they are prone to undergo excessive processing, and not because of a deficiency in C-NHEJ in subtelomeric regions.
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Affiliation(s)
- Keiko Muraki
- Department of Radiation Oncology, University of California, San Francisco, 2340 Sutter St. San Francisco, CA 94143-1330, USA
| | - Limei Han
- Department of Radiation Oncology, University of California, San Francisco, 2340 Sutter St. San Francisco, CA 94143-1330, USA
| | - Douglas Miller
- Department of Radiation Oncology, University of California, San Francisco, 2340 Sutter St. San Francisco, CA 94143-1330, USA
| | - John P Murnane
- Department of Radiation Oncology, University of California, San Francisco, 2340 Sutter St. San Francisco, CA 94143-1330, USA
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97
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Bellon M, Nicot C. Multiple Pathways Control the Reactivation of Telomerase in HTLV-I-Associated Leukemia. ACTA ACUST UNITED AC 2015; 2. [PMID: 26430700 DOI: 10.15436/2377-0902.15.017] [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] [Indexed: 12/29/2022]
Abstract
While telomerase (hTERT) activity is absent from normal somatic cells, reactivation of hTERT expression is a hallmark of cancer cells. Telomerase activity is required for avoiding replicative senescence and supports immortalization of cellular proliferation. Only a minority of cancer cells rely on a telomerase-independent process known as alternative lengthening of telomeres, ALT, to sustain cancer cell proliferation. Multiple genetic, epigenetic, and viral mechanisms have been found to de-regulate telomerase gene expression, thereby increasing the risk of cellular transformation. Here, we review the different strategies used by the Human T-cell leukemia virus type 1, HTLV-I, to activate hTERT expression and stimulate its enzymatic activity in virally infected CD4 T cells. The implications of hTERT reactivation in HTLV-I pathogenesis and disease treatment are discussed.
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Affiliation(s)
- Marcia Bellon
- Department of Pathology and Laboratory Medicine, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Christophe Nicot
- Department of Pathology and Laboratory Medicine, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
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98
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Mytych J, Pacyk K, Pepek M, Zebrowski J, Lewinska A, Wnuk M. Nanoparticle-mediated decrease of lamin B1 pools promotes a TRF protein-based adaptive response in cultured cells. Biomaterials 2015; 53:107-16. [PMID: 25890711 DOI: 10.1016/j.biomaterials.2015.02.072] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 02/08/2015] [Accepted: 02/15/2015] [Indexed: 12/30/2022]
Abstract
In general, nanoparticle-based materials are promising candidates for use in biological systems for diagnostic and therapeutic approaches. However, these materials' actions at the molecular level remain poorly understood. Nanoparticle (silica, silver and diamond)-induced oxidative stress and activation of the NF-κB pathway lead to the depletion of lamin B1 pools, which, in turn, results in upregulation of telomeric repeat binding factor (TRF) protein expression and maintenance of telomere length. In cancer cells, the TRF-based response is independent of the p53 pathway. In fibroblasts with active p53/p21 signaling, the levels of p53 and p21 are elevated and stress-induced premature senescence is observed. These results suggest that nanoparticles promote a telomere-focused cell adaptive response.
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Affiliation(s)
- Jennifer Mytych
- Department of Genetics, University of Rzeszow, Rejtana 16C, 35-959 Rzeszow, Poland
| | - Karolina Pacyk
- Department of Genetics, University of Rzeszow, Rejtana 16C, 35-959 Rzeszow, Poland
| | - Monika Pepek
- Department of Genetics, University of Rzeszow, Rejtana 16C, 35-959 Rzeszow, Poland
| | - Jacek Zebrowski
- Department of Plant Physiology, University of Rzeszow, Werynia 502, 36-100 Kolbuszowa, Poland
| | - Anna Lewinska
- Department of Biochemistry and Cell Biology, University of Rzeszow, Zelwerowicza 4, 35-601 Rzeszow, Poland
| | - Maciej Wnuk
- Department of Genetics, University of Rzeszow, Rejtana 16C, 35-959 Rzeszow, Poland.
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99
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Osterwald S, Deeg KI, Chung I, Parisotto D, Wörz S, Rohr K, Erfle H, Rippe K. PML induces compaction, TRF2 depletion and DNA damage signaling at telomeres and promotes their alternative lengthening. J Cell Sci 2015; 128:1887-1900. [DOI: 10.1242/jcs.148296] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
ABSTRACT
The alternative lengthening of telomeres (ALT) mechanism allows cancer cells to escape senescence and apoptosis in the absence of active telomerase. A characteristic feature of this pathway is the assembly of ALT-associated promyelocytic leukemia (PML) nuclear bodies (APBs) at telomeres. Here, we dissected the role of APBs in a human ALT cell line by performing an RNA interference screen using an automated 3D fluorescence microscopy platform and advanced 3D image analysis. We identified 29 proteins that affected APB formation, which included proteins involved in telomere and chromatin organization, protein sumoylation and DNA repair. By integrating and extending these findings, we found that APB formation induced clustering of telomere repeats, telomere compaction and concomitant depletion of the shelterin protein TRF2 (also known as TERF2). These APB-dependent changes correlated with the induction of a DNA damage response at telomeres in APBs as evident by a strong enrichment of the phosphorylated form of the ataxia telangiectasia mutated (ATM) kinase. Accordingly, we propose that APBs promote telomere maintenance by inducing a DNA damage response in ALT-positive tumor cells through changing the telomeric chromatin state to trigger ATM phosphorylation.
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Affiliation(s)
- Sarah Osterwald
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
| | - Katharina I. Deeg
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
| | - Inn Chung
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
| | - Daniel Parisotto
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
| | - Stefan Wörz
- Department of Bioinformatics and Functional Genomics, Biomedical Computer Vision Group, University of Heidelberg & DKFZ, BioQuant, IPMB, 69120 Heidelberg, Germany
| | - Karl Rohr
- Department of Bioinformatics and Functional Genomics, Biomedical Computer Vision Group, University of Heidelberg & DKFZ, BioQuant, IPMB, 69120 Heidelberg, Germany
| | - Holger Erfle
- ViroQuant-CellNetworks RNAi Screening Facility, University of Heidelberg & BioQuant, 69120 Heidelberg, Germany
| | - Karsten Rippe
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
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100
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Feuerhahn S, Chen LY, Luke B, Porro A. No DDRama at chromosome ends: TRF2 takes centre stage. Trends Biochem Sci 2015; 40:275-85. [DOI: 10.1016/j.tibs.2015.03.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 03/06/2015] [Accepted: 03/06/2015] [Indexed: 12/13/2022]
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