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Córdova-Oriz I, Polonio AM, Cuadrado-Torroglosa I, Chico-Sordo L, Medrano M, García-Velasco JA, Varela E. Chromosome ends and the theory of marginotomy: implications for reproduction. Biogerontology 2024; 25:227-248. [PMID: 37943366 DOI: 10.1007/s10522-023-10071-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/21/2023] [Indexed: 11/10/2023]
Abstract
Telomeres are the protective structures located at the ends of linear chromosomes. They were first described in the 1930s, but their biology remained unexplored until the early 70s, when Alexey M. Olovnikov, a theoretical biologist, suggested that telomeres cannot be fully copied during DNA replication. He proposed a theory that linked this phenomenon with the limit of cell proliferation capacity and the "duration of life" (theory of marginotomy), and suggested a potential of telomere lenghthening for the prevention of aging (anti-marginotomy). The impact of proliferative telomere shortening on life expectancy was later confirmed. In humans, telomere shortening is counteracted by telomerase, an enzyme that is undetectable in most adult somatic cells, but present in cancer cells and adult and embryonic stem and germ cells. Although telomere length dynamics are different in male and female gametes during gametogenesis, telomere lengths are reset at the blastocyst stage, setting the initial length of the species. The role of the telomere pathway in reproduction has been explored for years, mainly because of increased infertility resulting from delayed childbearing. Short telomere length in ovarian somatic cells is associated to decreased fertility and higher aneuploidy rates in embryos. Consequently, there is a growing interest in telomere lengthening strategies, aimed at improving fertility. It has also been observed that lifestyle factors can affect telomere length and improve fertility outcomes. In this review, we discuss the implications of telomere theory in fertility, especially in oocytes, spermatozoa, and embryos, as well as therapies to enhance reproductive success.
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Affiliation(s)
- Isabel Córdova-Oriz
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Alba M Polonio
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Isabel Cuadrado-Torroglosa
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Lucía Chico-Sordo
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Marta Medrano
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Juan A García-Velasco
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
- IVIRMA Global Research Alliance, IVIRMA Madrid, Madrid, Spain
- Department of Medical Specialties and Public Health, Edificio Departamental II, Rey Juan Carlos University, Av. de Atenas, s/n, 28922, Alcorcón, Madrid, Spain
| | - Elisa Varela
- IVIRMA Global Research Alliance, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain.
- Department of Medical Specialties and Public Health, Edificio Departamental II, Rey Juan Carlos University, Av. de Atenas, s/n, 28922, Alcorcón, Madrid, Spain.
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2
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Bournaka S, Badra-Fajardo N, Arbi M, Taraviras S, Lygerou Z. The cell cycle revisited: DNA replication past S phase preserves genome integrity. Semin Cancer Biol 2024; 99:45-55. [PMID: 38346544 DOI: 10.1016/j.semcancer.2024.02.002] [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] [Received: 11/27/2023] [Revised: 01/23/2024] [Accepted: 02/05/2024] [Indexed: 02/20/2024]
Abstract
Accurate and complete DNA duplication is critical for maintaining genome integrity. Multiple mechanisms regulate when and where DNA replication takes place, to ensure that the entire genome is duplicated once and only once per cell cycle. Although the bulk of the genome is copied during the S phase of the cell cycle, increasing evidence suggests that parts of the genome are replicated in G2 or mitosis, in a last attempt to secure that daughter cells inherit an accurate copy of parental DNA. Remaining unreplicated gaps may be passed down to progeny and replicated in the next G1 or S phase. These findings challenge the long-established view that genome duplication occurs strictly during the S phase, bridging DNA replication to DNA repair and providing novel therapeutic strategies for cancer treatment.
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Affiliation(s)
- Spyridoula Bournaka
- Department of General Biology, Medical School, University of Patras, Patras 26504, Greece
| | - Nibal Badra-Fajardo
- Department of General Biology, Medical School, University of Patras, Patras 26504, Greece
| | - Marina Arbi
- Department of General Biology, Medical School, University of Patras, Patras 26504, Greece
| | - Stavros Taraviras
- Department of Physiology, Medical School, University of Patras, Patras 26504, Greece
| | - Zoi Lygerou
- Department of General Biology, Medical School, University of Patras, Patras 26504, Greece.
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3
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Udroiu I, Marinaccio J, Sgura A. Effects of p53 and ATRX inhibition on telomeric recombination in aging fibroblasts. Front Oncol 2024; 14:1322438. [PMID: 38333682 PMCID: PMC10850245 DOI: 10.3389/fonc.2024.1322438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/11/2024] [Indexed: 02/10/2024] Open
Abstract
In order to avoid replicative senescence, tumor cells must acquire a telomere maintenance mechanism. Beside telomerase activation, a minority of tumors employs a recombinational mechanism called Alternative Lengthening of Telomeres (ALT). Several studies have investigated the potential ALT stimulation by inactivation of ATRX in tumor cells, obtaining contrasting results. Differently, since ALT can be viewed as a mechanism to overcome telomere shortening-mediated replicative senescence, we have investigated the effects of the inhibition of ATRX and p53 in aging primary fibroblasts. We observed that senescence leads to a phenotype that seems permissive for ALT activity, i.e. high levels of ALT-associated PML bodies (APB), telomeric damage and telomeric cohesion. On the other hand, RAD51 is highly repressed and thus telomeric recombination, upon which the ALT machinery relies, is almost absent. Silencing of ATRX greatly increases telomeric recombination in young cells, but is not able to overcome senescence-induced repression of homologous recombination. Conversely, inhibition of both p53 and ATRX leads to a phenotype reminiscent of some aspects of ALT activity, with a further increase of APB, a decrease of telomere shortening (and increased proliferation) and, above all, an increase of telomeric recombination.
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Affiliation(s)
- Ion Udroiu
- Dipartimento di Scienze, Università “Roma Tre“, Rome, Italy
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4
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Rosso I, Jones-Weinert C, Rossiello F, Cabrini M, Brambillasca S, Munoz-Sagredo L, Lavagnino Z, Martini E, Tedone E, Garre' M, Aguado J, Parazzoli D, Mione M, Shay JW, Mercurio C, d'Adda di Fagagna F. Alternative lengthening of telomeres (ALT) cells viability is dependent on C-rich telomeric RNAs. Nat Commun 2023; 14:7086. [PMID: 37925537 PMCID: PMC10625592 DOI: 10.1038/s41467-023-42831-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 10/23/2023] [Indexed: 11/06/2023] Open
Abstract
Alternative lengthening of telomeres (ALT) is a telomere maintenance mechanism activated in ~10-15% of cancers, characterized by telomeric damage. Telomeric damage-induced long non-coding RNAs (dilncRNAs) are transcribed at dysfunctional telomeres and contribute to telomeric DNA damage response (DDR) activation and repair. Here we observed that telomeric dilncRNAs are preferentially elevated in ALT cells. Inhibition of C-rich (teloC) dilncRNAs with antisense oligonucleotides leads to DNA replication stress responses, increased genomic instability, and apoptosis induction selectively in ALT cells. Cell death is dependent on DNA replication and is increased by DNA replication stress. Mechanistically, teloC dilncRNA inhibition reduces RAD51 and 53BP1 recruitment to telomeres, boosts the engagement of BIR machinery, and increases C-circles and telomeric sister chromatid exchanges, without increasing telomeric non-S phase synthesis. These results indicate that teloC dilncRNA is necessary for a coordinated recruitment of DDR factors to ALT telomeres and it is essential for ALT cancer cells survival.
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Affiliation(s)
- Ilaria Rosso
- IFOM ETS - The AIRC Institute of Molecular Oncology, Milan, Italy
| | - Corey Jones-Weinert
- IFOM ETS - The AIRC Institute of Molecular Oncology, Milan, Italy
- The Salk Institute for Biological Studies, La Jolla, CA, USA
| | | | - Matteo Cabrini
- IFOM ETS - The AIRC Institute of Molecular Oncology, Milan, Italy
| | - Silvia Brambillasca
- IFOM ETS - The AIRC Institute of Molecular Oncology (Experimental Therapeutics Program), Milan, Italy
| | - Leonel Munoz-Sagredo
- Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- School of Medicine, Universidad de Valparaiso, Valparaiso, Chile
| | - Zeno Lavagnino
- IFOM ETS - The AIRC Institute of Molecular Oncology, Milan, Italy
| | - Emanuele Martini
- IFOM ETS - The AIRC Institute of Molecular Oncology, Milan, Italy
- Dipartimento di Oncologia ed Emato-Oncologia, Università degli Studi di Milano, Milan, Italy
| | - Enzo Tedone
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Massimiliano Garre'
- IFOM ETS - The AIRC Institute of Molecular Oncology, Milan, Italy
- RCSI, Royal College of Surgeons in Ireland, Department of Chemistry, Dublin, Ireland
| | - Julio Aguado
- IFOM ETS - The AIRC Institute of Molecular Oncology, Milan, Italy
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD, Australia
| | - Dario Parazzoli
- IFOM ETS - The AIRC Institute of Molecular Oncology, Milan, Italy
| | - Marina Mione
- Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Trento, Italy
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ciro Mercurio
- IFOM ETS - The AIRC Institute of Molecular Oncology (Experimental Therapeutics Program), Milan, Italy
| | - Fabrizio d'Adda di Fagagna
- IFOM ETS - The AIRC Institute of Molecular Oncology, Milan, Italy.
- Institute of Molecular Genetics IGM-CNR "Luigi Luca Cavalli-Sforza", Pavia, Italy.
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5
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Jin R, Niu C, Wu F, Zhou S, Han T, Zhang Z, Li E, Zhang X, Xu S, Wang J, Tian S, Chen W, Ye Q, Cao C, Cheng L. DNA damage contributes to age-associated differences in SARS-CoV-2 infection. Aging Cell 2022; 21:e13729. [PMID: 36254583 PMCID: PMC9741512 DOI: 10.1111/acel.13729] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 09/01/2022] [Accepted: 09/26/2022] [Indexed: 12/14/2022] Open
Abstract
Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is known to disproportionately affect older individuals. How aging processes affect SARS-CoV-2 infection and disease progression remains largely unknown. Here, we found that DNA damage, one of the hallmarks of aging, promoted SARS-CoV-2 infection in vitro and in vivo. SARS-CoV-2 entry was facilitated by DNA damage caused by extrinsic genotoxic stress or telomere dysfunction and hampered by inhibition of the DNA damage response (DDR). Mechanistic analysis revealed that DDR increased expression of angiotensin-converting enzyme 2 (ACE2), the primary receptor of SARS-CoV-2, by activation of transcription factor c-Jun. Importantly, in vivo experiment using a mouse-adapted viral strain also verified the significant roles of DNA damage in viral entry and severity of infection. Expression of ACE2 was elevated in the older human and mice tissues and positively correlated with γH2AX, a DNA damage biomarker, and phosphorylated c-Jun (p-c-Jun). Finally, nicotinamide mononucleotide (NMN) and MDL-800, which promote DNA repair, alleviated SARS-CoV-2 infection and disease severity in vitro and in vivo. Taken together, our data provide insights into the age-associated differences in SARS-CoV-2 infection and a novel approach for antiviral intervention.
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Affiliation(s)
- Rui Jin
- Beijing Institute of BiotechnologyBeijingChina
| | - Chang Niu
- College of Life SciencesCapital Normal UniversityBeijingChina
| | - Fengyun Wu
- College of Life SciencesCapital Normal UniversityBeijingChina
| | - Sixin Zhou
- Department of SurgeryChinese PLA General HospitalBeijingChina
| | - Tao Han
- BaYi Children's Hospital, the Seventh Medical CenterChinese PLA General HospitalBeijingChina
| | - Zhe Zhang
- Beijing Institute of BiotechnologyBeijingChina
| | - Entao Li
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research InstituteChinese Academy of Agricultural SciencesChangchunChina
| | - Xiaona Zhang
- College of Life SciencesCapital Normal UniversityBeijingChina
| | - Shanrong Xu
- School of Life ScienceAnqing Normal UniversityAnqingChina
| | - Jiadong Wang
- Department of Radiation Medicine, School of Basic Medical Sciences, Institute of Systems BiomedicinePeking University Health Science CenterBeijingChina
| | - Shen Tian
- College of Life SciencesCapital Normal UniversityBeijingChina
| | - Wei Chen
- Beijing Institute of BiotechnologyBeijingChina
| | - Qinong Ye
- Beijing Institute of BiotechnologyBeijingChina
| | - Cheng Cao
- Beijing Institute of BiotechnologyBeijingChina
| | - Long Cheng
- Beijing Institute of BiotechnologyBeijingChina
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6
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Buemi V, Schillaci O, Santorsola M, Bonazza D, Broccia PV, Zappone A, Bottin C, Dell'Omo G, Kengne S, Cacchione S, Raffa GD, Piazza S, di Fagagna FD, Benetti R, Cortale M, Zanconati F, Del Sal G, Schoeftner S. TGS1 mediates 2,2,7-trimethyl guanosine capping of the human telomerase RNA to direct telomerase dependent telomere maintenance. Nat Commun 2022; 13:2302. [PMID: 35484160 PMCID: PMC9050681 DOI: 10.1038/s41467-022-29907-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 03/25/2022] [Indexed: 11/21/2022] Open
Abstract
Pathways that direct the selection of the telomerase-dependent or recombination-based, alternative lengthening of telomere (ALT) maintenance pathway in cancer cells are poorly understood. Using human lung cancer cells and tumor organoids we show that formation of the 2,2,7-trimethylguanosine (TMG) cap structure at the human telomerase RNA 5′ end by the Trimethylguanosine Synthase 1 (TGS1) is central for recruiting telomerase to telomeres and engaging Cajal bodies in telomere maintenance. TGS1 depletion or inhibition by the natural nucleoside sinefungin impairs telomerase recruitment to telomeres leading to Exonuclease 1 mediated generation of telomere 3′ end protrusions that engage in RAD51-dependent, homology directed recombination and the activation of key features of the ALT pathway. This indicates a critical role for 2,2,7-TMG capping of the RNA component of human telomerase (hTR) in enforcing telomerase-dependent telomere maintenance to restrict the formation of telomeric substrates conductive to ALT. Our work introduces a targetable pathway of telomere maintenance that holds relevance for telomere-related diseases such as cancer and aging. Telomerase protects chromosome ends in stem cells and cancer cells. Here the authors show that Trimethylguaonsine Synthase 1 (TGS-1) – dependent trimethylguanosine capping of the RNA component of the human telomerase complex has an important role in directing telomere dependent telomere maintenance and suppressing the ALT pathway in cancer cells.
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Affiliation(s)
- Valentina Buemi
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy.,Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, London, SM2 5NG, United Kingdom
| | - Odessa Schillaci
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy
| | - Mariangela Santorsola
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy
| | - Deborah Bonazza
- Struttura Complessa di Anatomia ed Istologia Patologica, Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI) Trieste, Strada di Fiume 447, 34149, Trieste, Italy
| | - Pamela Veneziano Broccia
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy
| | - Annie Zappone
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy
| | - Cristina Bottin
- Dipartimento Universitario Clinico di Scienze Mediche Chirurgiche e della Salute, Università degli Studi di Trieste, Ospedale di Cattinara - Strada di Fiume 447, 34149, Trieste, Italy
| | - Giulia Dell'Omo
- IFOM Foundation-FIRC Institute of Molecular Oncology Foundation, Milan, 20139, Italy
| | - Sylvie Kengne
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy
| | - Stefano Cacchione
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy
| | - Grazia Daniela Raffa
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy
| | - Silvano Piazza
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Area Science Park - Padriciano, 34149, Trieste, Italy
| | - Fabrizio d'Adda di Fagagna
- IFOM Foundation-FIRC Institute of Molecular Oncology Foundation, Milan, 20139, Italy.,Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Pavia, 27100, Italy
| | - Roberta Benetti
- Dipartimento di Area Medica (Dame), Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Maurizio Cortale
- Struttura Complessa di Chirurgia Toracica, Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI) Trieste, Strada di Fiume 447, 34149, Trieste, Italy
| | - Fabrizio Zanconati
- Struttura Complessa di Anatomia ed Istologia Patologica, Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI) Trieste, Strada di Fiume 447, 34149, Trieste, Italy.,Dipartimento Universitario Clinico di Scienze Mediche Chirurgiche e della Salute, Università degli Studi di Trieste, Ospedale di Cattinara - Strada di Fiume 447, 34149, Trieste, Italy
| | - Giannino Del Sal
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy.,IFOM Foundation-FIRC Institute of Molecular Oncology Foundation, Milan, 20139, Italy.,International Centre for Genetic Engineering and Biotechnology (ICGEB), Area Science Park - Padriciano, 34149, Trieste, Italy
| | - Stefan Schoeftner
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy.
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7
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CRISPR/Cas: A New Tool in the Research of Telomeres and Telomerase as Well as a Novel Form of Cancer Therapy. Int J Mol Sci 2022; 23:ijms23063002. [PMID: 35328421 PMCID: PMC8953708 DOI: 10.3390/ijms23063002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 02/28/2022] [Accepted: 03/08/2022] [Indexed: 02/01/2023] Open
Abstract
Due to their close connection with senescence, aging, and disease, telomeres and telomerase provide a unique and vital research route for boosting longevity and health span. Despite significant advances during the last three decades, earlier studies into these two biological players were impeded by the difficulty of achieving real-time changes inside living cells. As a result of the clustered regularly interspaced short palindromic repeats (CRISPR)-associated system’s (Cas) method, targeted genetic studies are now underway to change telomerase, the genes that govern it as well as telomeres. This review will discuss studies that have utilized CRISPR-related technologies to target and modify genes relevant to telomeres and telomerase as well as to develop targeted anti-cancer therapies. These studies greatly improve our knowledge and understanding of cellular and molecular mechanisms that underlie cancer development and aging.
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8
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Lezaja A, Panagopoulos A, Wen Y, Carvalho E, Imhof R, Altmeyer M. RPA shields inherited DNA lesions for post-mitotic DNA synthesis. Nat Commun 2021; 12:3827. [PMID: 34158486 PMCID: PMC8219667 DOI: 10.1038/s41467-021-23806-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 05/11/2021] [Indexed: 02/05/2023] Open
Abstract
The paradigm that checkpoints halt cell cycle progression for genome repair has been challenged by the recent discovery of heritable DNA lesions escaping checkpoint control. How such inherited lesions affect genome function and integrity is not well understood. Here, we identify a new class of heritable DNA lesions, which is marked by replication protein A (RPA), a protein primarily known for shielding single-stranded DNA in S/G2. We demonstrate that post-mitotic RPA foci occur at low frequency during unperturbed cell cycle progression, originate from the previous cell cycle, and are exacerbated upon replication stress. RPA-marked inherited ssDNA lesions are found at telomeres, particularly of ALT-positive cancer cells. We reveal that RPA protects these replication remnants in G1 to allow for post-mitotic DNA synthesis (post-MiDAS). Given that ALT-positive cancer cells exhibit high levels of replication stress and telomere fragility, targeting post-MiDAS might be a new therapeutic opportunity.
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Affiliation(s)
- Aleksandra Lezaja
- grid.7400.30000 0004 1937 0650Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Andreas Panagopoulos
- grid.7400.30000 0004 1937 0650Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Yanlin Wen
- grid.7400.30000 0004 1937 0650Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Edison Carvalho
- grid.7400.30000 0004 1937 0650Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Ralph Imhof
- grid.7400.30000 0004 1937 0650Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- grid.7400.30000 0004 1937 0650Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
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9
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Nie M, Oravcová M, Jami‐Alahmadi Y, Wohlschlegel JA, Lazzerini‐Denchi E, Boddy MN. FAM111A induces nuclear dysfunction in disease and viral restriction. EMBO Rep 2021; 22:e50803. [PMID: 33369867 PMCID: PMC7857424 DOI: 10.15252/embr.202050803] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 11/17/2020] [Accepted: 11/20/2020] [Indexed: 12/13/2022] Open
Abstract
Mutations in the nuclear trypsin-like serine protease FAM111A cause Kenny-Caffey syndrome (KCS2) with hypoparathyroidism and skeletal dysplasia or perinatally lethal osteocraniostenosis (OCS). In addition, FAM111A was identified as a restriction factor for certain host range mutants of the SV40 polyomavirus and VACV orthopoxvirus. However, because FAM111A function is poorly characterized, its roles in restricting viral replication and the etiology of KCS2 and OCS remain undefined. We find that FAM111A KCS2 and OCS patient mutants are hyperactive and cytotoxic, inducing apoptosis-like phenotypes such as disruption of nuclear structure and pore distribution, in a protease-dependent manner. Moreover, wild-type FAM111A activity causes similar nuclear phenotypes, including the loss of nuclear barrier function, when SV40 host range mutants attempt to replicate in restrictive cells. Interestingly, pan-caspase inhibitors do not block these FAM111A-induced phenotypes, implying it acts independently or upstream of caspases. In this regard, we identify nucleoporins and the associated GANP transcription/replication factor as FAM111A interactors and candidate targets. Overall, we reveal a potentially unifying mechanism through which deregulated FAM111A activity restricts viral replication and causes KCS2 and OCS.
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Affiliation(s)
- Minghua Nie
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaCAUSA
| | - Martina Oravcová
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaCAUSA
| | - Yasaman Jami‐Alahmadi
- Department of Biological ChemistryDavid Geffen School of MedicineUniversity of CaliforniaLos AngelesCAUSA
| | - James A Wohlschlegel
- Department of Biological ChemistryDavid Geffen School of MedicineUniversity of CaliforniaLos AngelesCAUSA
| | | | - Michael N Boddy
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaCAUSA
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10
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Fani L, Hilal S, Sedaghat S, Broer L, Licher S, Arp PP, van Meurs JBJ, Ikram MK, Ikram MA. Telomere Length and the Risk of Alzheimer's Disease: The Rotterdam Study. J Alzheimers Dis 2020; 73:707-714. [PMID: 31839608 PMCID: PMC7029372 DOI: 10.3233/jad-190759] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
There is a wide interest in biomarkers that capture the burden of detrimental factors as these accumulate with the passage of time, i.e., increasing age. Telomere length has received considerable attention as such a marker, because it is easily quantified and it may aid in disentangling the etiology of dementia or serve as predictive marker. We determined the association of telomere length with risk of Alzheimer’s disease and all-cause dementia in a population-based setting. Within the Rotterdam Study, we performed quantitative PCR to measure mean leukocyte telomere length in blood. We determined the association of telomere length with risk of Alzheimer’s disease until 2016, using Cox regression models. Of 1,961 participants (mean age 71.4±9.3 years, 57.1% women) with a median follow-up of 8.3 years, 237 individuals were diagnosed with Alzheimer’s disease. We found a U-shaped association between telomere length and risk of Alzheimer’s disease: compared to the middle tertile the adjusted hazard ratio was 1.59 (95% confidence interval (CI), 1.13–2.23) for the lowest tertile and 1.47 (1.03–2.10) for the highest tertile. Results were similarly U-shaped but slightly attenuated for all-cause dementia. In conclusion, shorter and longer telomere length are both associated with an increased risk of Alzheimer’s disease in the general population.
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Affiliation(s)
- Lana Fani
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Saima Hilal
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands.,Department of Neurology, Erasmus MC, Rotterdam, The Netherlands
| | - Sanaz Sedaghat
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands.,Department of Preventive Medicine, Feinberg School of Medicine Northwestern University, Chicago, IL, USA
| | - Linda Broer
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Silvan Licher
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Pascal P Arp
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | | | - M Kamran Ikram
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands.,Department of Neurology, Erasmus MC, Rotterdam, The Netherlands
| | - M Arfan Ikram
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands
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11
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Shi G, Hu Y, Zhu X, Jiang Y, Pang J, Wang C, Huang W, Zhao Y, Ma W, Liu D, Huang J, Songyang Z. A critical role of telomere chromatin compaction in ALT tumor cell growth. Nucleic Acids Res 2020; 48:6019-6031. [PMID: 32379321 PMCID: PMC7293046 DOI: 10.1093/nar/gkaa224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/17/2020] [Accepted: 04/18/2020] [Indexed: 01/15/2023] Open
Abstract
ALT tumor cells often contain abundant DNA damage foci at telomeres and rely on the alternative lengthening of telomeres (ALT) mechanism to maintain their telomeres. How the telomere chromatin is regulated and maintained in these cells remains largely unknown. In this study, we present evidence that heterochromatin protein 1 binding protein 3 (HP1BP3) can localize to telomeres and is particularly enriched on telomeres in ALT cells. HP1BP3 inhibition led to preferential growth inhibition of ALT cells, which was accompanied by telomere chromatin decompaction, increased presence of C-circles, more pronounced ALT-associated phenotypes and elongated telomeres. Furthermore, HP1BP3 appeared to participate in regulating telomere histone H3K9me3 epigenetic marks. Taken together, our data suggest that HP1BP3 functions on telomeres to maintain telomere chromatin and represents a novel target for inhibiting ALT cancer cells.
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Affiliation(s)
- Guang Shi
- MOE Key Laboratory of Gene Function and Regulation, Guangzhou Key Laboratory of Healthy Aging Research and SYSU-BCM Joint Research Center, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.,Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Yang Hu
- MOE Key Laboratory of Gene Function and Regulation, Guangzhou Key Laboratory of Healthy Aging Research and SYSU-BCM Joint Research Center, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Xing Zhu
- MOE Key Laboratory of Gene Function and Regulation, Guangzhou Key Laboratory of Healthy Aging Research and SYSU-BCM Joint Research Center, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Yuanling Jiang
- MOE Key Laboratory of Gene Function and Regulation, Guangzhou Key Laboratory of Healthy Aging Research and SYSU-BCM Joint Research Center, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Junjie Pang
- MOE Key Laboratory of Gene Function and Regulation, Guangzhou Key Laboratory of Healthy Aging Research and SYSU-BCM Joint Research Center, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Chuanle Wang
- MOE Key Laboratory of Gene Function and Regulation, Guangzhou Key Laboratory of Healthy Aging Research and SYSU-BCM Joint Research Center, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Wenjun Huang
- MOE Key Laboratory of Gene Function and Regulation, Guangzhou Key Laboratory of Healthy Aging Research and SYSU-BCM Joint Research Center, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Yong Zhao
- MOE Key Laboratory of Gene Function and Regulation, Guangzhou Key Laboratory of Healthy Aging Research and SYSU-BCM Joint Research Center, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Wenbin Ma
- MOE Key Laboratory of Gene Function and Regulation, Guangzhou Key Laboratory of Healthy Aging Research and SYSU-BCM Joint Research Center, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Dan Liu
- Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA 77030
| | - Junjiu Huang
- MOE Key Laboratory of Gene Function and Regulation, Guangzhou Key Laboratory of Healthy Aging Research and SYSU-BCM Joint Research Center, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.,Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Zhou Songyang
- MOE Key Laboratory of Gene Function and Regulation, Guangzhou Key Laboratory of Healthy Aging Research and SYSU-BCM Joint Research Center, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.,Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China.,Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA 77030.,State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
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12
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Guterres AN, Villanueva J. Targeting telomerase for cancer therapy. Oncogene 2020; 39:5811-5824. [PMID: 32733068 PMCID: PMC7678952 DOI: 10.1038/s41388-020-01405-w] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 07/02/2020] [Accepted: 07/23/2020] [Indexed: 12/20/2022]
Abstract
Telomere maintenance via telomerase reactivation is a nearly universal hallmark of cancer cells which enables replicative immortality. In contrast, telomerase activity is silenced in most adult somatic cells. Thus, telomerase represents an attractive target for highly selective cancer therapeutics. However, development of telomerase inhibitors has been challenging and thus far there are no clinically approved strategies exploiting this cancer target. The discovery of prevalent mutations in the TERT promoter region in many cancers and recent advances in telomerase biology has led to a renewed interest in targeting this enzyme. Here we discuss recent efforts targeting telomerase, including immunotherapies and direct telomerase inhibitors, as well as emerging approaches such as targeting TERT gene expression driven by TERT promoter mutations. We also address some of the challenges to telomerase-directed therapies including potential therapeutic resistance and considerations for future therapeutic applications and translation into the clinical setting. Although much work remains to be done, effective strategies targeting telomerase will have a transformative impact for cancer therapy and the prospect of clinically effective drugs is boosted by recent advances in structural models of human telomerase.
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Affiliation(s)
- Adam N Guterres
- Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, PA, USA
| | - Jessie Villanueva
- Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, PA, USA.
- Melanoma Research Center, The Wistar Institute, Philadelphia, PA, USA.
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13
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Loe TK, Li JSZ, Zhang Y, Azeroglu B, Boddy MN, Denchi EL. Telomere length heterogeneity in ALT cells is maintained by PML-dependent localization of the BTR complex to telomeres. Genes Dev 2020; 34:650-662. [PMID: 32217664 PMCID: PMC7197349 DOI: 10.1101/gad.333963.119] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 02/26/2020] [Indexed: 12/11/2022]
Abstract
In this study, Loe et al. sought to understand ALT-associated PML bodies (APBs) and their function in the alternative lengthening of telomeres (ALT) pathway, a telomerase-independent mechanism of telomere extension that some cancer cells that use. Using CRISPR/Cas9 to delete PML and APB components from ALT-positive cells, they found that PML is required for the ALT mechanism, and that this necessity stems from APBs’ role in localizing the BLM–TOP3A–RMI (BTR) complex to ALT telomere ends, suggesting that BTR localization to telomeres is sufficient to sustain ALT activity. Telomeres consist of TTAGGG repeats bound by protein complexes that serve to protect the natural end of linear chromosomes. Most cells maintain telomere repeat lengths by using the enzyme telomerase, although there are some cancer cells that use a telomerase-independent mechanism of telomere extension, termed alternative lengthening of telomeres (ALT). Cells that use ALT are characterized, in part, by the presence of specialized PML nuclear bodies called ALT-associated PML bodies (APBs). APBs localize to and cluster telomeric ends together with telomeric and DNA damage factors, which led to the proposal that these bodies act as a platform on which ALT can occur. However, the necessity of APBs and their function in the ALT pathway has remained unclear. Here, we used CRISPR/Cas9 to delete PML and APB components from ALT-positive cells to cleanly define the function of APBs in ALT. We found that PML is required for the ALT mechanism, and that this necessity stems from APBs’ role in localizing the BLM–TOP3A–RMI (BTR) complex to ALT telomere ends. Strikingly, recruitment of the BTR complex to telomeres in a PML-independent manner bypasses the need for PML in the ALT pathway, suggesting that BTR localization to telomeres is sufficient to sustain ALT activity.
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Affiliation(s)
- Taylor K Loe
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Julia Su Zhou Li
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093, USA
| | - Yuxiang Zhang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Benura Azeroglu
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Michael Nicholas Boddy
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Eros Lazzerini Denchi
- Laboratory of Genome Integrity, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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14
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Sommer A, Royle NJ. ALT: A Multi-Faceted Phenomenon. Genes (Basel) 2020; 11:E133. [PMID: 32012790 PMCID: PMC7073516 DOI: 10.3390/genes11020133] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/17/2020] [Accepted: 01/22/2020] [Indexed: 01/13/2023] Open
Abstract
One of the hallmarks of cancer cells is their indefinite replicative potential, made possible by the activation of a telomere maintenance mechanism (TMM). The majority of cancers reactivate the reverse transcriptase, telomerase, to maintain their telomere length but a minority (10% to 15%) utilize an alternative lengthening of telomeres (ALT) pathway. Here, we review the phenotypes and molecular markers specific to ALT, and investigate the significance of telomere mutations and sequence variation in ALT cell lines. We also look at the recent advancements in understanding the different mechanisms behind ALT telomere elongation and finally, the progress made in identifying potential ALT-targeted therapies, including those already in use for the treatment of both hematological and solid tumors.
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Affiliation(s)
| | - Nicola J. Royle
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK;
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15
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Kent T, Gracias D, Shepherd S, Clynes D. Alternative Lengthening of Telomeres in Pediatric Cancer: Mechanisms to Therapies. Front Oncol 2020; 9:1518. [PMID: 32039009 PMCID: PMC6985284 DOI: 10.3389/fonc.2019.01518] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 12/17/2019] [Indexed: 12/26/2022] Open
Abstract
Achieving replicative immortality is a crucial step in tumorigenesis and requires both bypassing cell cycle checkpoints and the extension of telomeres, sequences that protect the distal ends of chromosomes during replication. In the majority of cancers this is achieved through the enzyme telomerase, however a subset of cancers instead utilize a telomerase-independent mechanism of telomere elongation-the Alternative Lengthening of Telomeres (ALT) pathway. Recent work has aimed to decipher the exact mechanism that underlies this pathway. To this end, this pathway has now been shown to extend telomeres through exploitation of DNA repair machinery in a unique process that may present a number of druggable targets. The identification of such targets, and the subsequent development or repurposing of therapies to these targets may be crucial to improving the prognosis for many ALT-positive cancers, wherein mean survival is lower than non-ALT counterparts and the cancers themselves are particularly unresponsive to standard of care therapies. In this review we summarize the recent identification of many aspects of the ALT pathway, and the therapies that may be employed to exploit these new targets.
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Affiliation(s)
- Thomas Kent
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Deanne Gracias
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Samuel Shepherd
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - David Clynes
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
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16
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Graham MK, Kim J, Da J, Brosnan-Cashman JA, Rizzo A, Baena Del Valle JA, Chia L, Rubenstein M, Davis C, Zheng Q, Cope L, Considine M, Haffner MC, De Marzo AM, Meeker AK, Heaphy CM. Functional Loss of ATRX and TERC Activates Alternative Lengthening of Telomeres (ALT) in LAPC4 Prostate Cancer Cells. Mol Cancer Res 2019; 17:2480-2491. [PMID: 31611308 DOI: 10.1158/1541-7786.mcr-19-0654] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/06/2019] [Accepted: 10/07/2019] [Indexed: 01/06/2023]
Abstract
A key hallmark of cancer, unlimited replication, requires cancer cells to evade both replicative senescence and potentially lethal chromosomal instability induced by telomere dysfunction. The majority of cancers overcome these critical barriers by upregulating telomerase, a telomere-specific reverse transcriptase. However, a subset of cancers maintains telomere lengths by the telomerase-independent Alternative Lengthening of Telomeres (ALT) pathway. The presence of ALT is strongly associated with recurrent cancer-specific somatic inactivating mutations in the ATRX-DAXX chromatin-remodeling complex. Here, we generate an ALT-positive adenocarcinoma cell line following functional inactivation of ATRX and telomerase in a telomerase-positive adenocarcinoma cell line. Inactivating mutations in ATRX were introduced using CRISPR-cas9 nickase into two prostate cancer cell lines, LAPC-4 (derived from a lymph node metastasis) and CWR22Rv1 (sourced from a xenograft established from a primary prostate cancer). In LAPC-4, but not CWR22Rv1, abolishing ATRX was sufficient to induce multiple ALT-associated hallmarks, including the presence of ALT-associated promyelocytic leukemia bodies (APB), extrachromosomal telomere C-circles, and dramatic telomere length heterogeneity. However, telomerase activity was still present in these ATRXKO cells. Telomerase activity was subsequently crippled in these LAPC-4 ATRXKO cells by introducing mutations in the TERC locus, the essential RNA component of telomerase. These LAPC-4 ATRXKO TERCmut cells continued to proliferate long-term and retained ALT-associated hallmarks, thereby demonstrating their reliance on the ALT mechanism for telomere maintenance. IMPLICATIONS: These prostate cancer cell line models provide a unique system to explore the distinct molecular alterations that occur upon induction of ALT, and may be useful tools to screen for ALT-specific therapies.
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Affiliation(s)
- Mindy K Graham
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jiyoung Kim
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Joseph Da
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Anthony Rizzo
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Lionel Chia
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Michael Rubenstein
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland
| | - Christine Davis
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Qizhi Zheng
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Leslie Cope
- Department of Oncology Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Michael Considine
- Department of Oncology Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Michael C Haffner
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Angelo M De Marzo
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Oncology Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Alan K Meeker
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Oncology Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Christopher M Heaphy
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland. .,Department of Oncology Johns Hopkins University School of Medicine, Baltimore, Maryland
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17
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Affiliation(s)
- Jaewon Min
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jerry W. Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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18
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Replication Stress Response Links RAD52 to Protecting Common Fragile Sites. Cancers (Basel) 2019; 11:cancers11101467. [PMID: 31569559 PMCID: PMC6826974 DOI: 10.3390/cancers11101467] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 09/20/2019] [Accepted: 09/23/2019] [Indexed: 12/20/2022] Open
Abstract
Rad52 in yeast is a key player in homologous recombination (HR), but mammalian RAD52 is dispensable for HR as shown by the lack of a strong HR phenotype in RAD52-deficient cells and in RAD52 knockout mice. RAD52 function in mammalian cells first emerged with the discovery of its important backup role to BRCA (breast cancer genes) in HR. Recent new evidence further demonstrates that RAD52 possesses multiple activities to cope with replication stress. For example, replication stress-induced DNA repair synthesis in mitosis (MiDAS) and oncogene overexpression-induced DNA replication are dependent on RAD52. RAD52 becomes essential in HR to repair DSBs containing secondary structures, which often arise at collapsed replication forks. RAD52 is also implicated in break-induced replication (BIR) and is found to inhibit excessive fork reversal at stalled replication forks. These various functions of RAD52 to deal with replication stress have been linked to the protection of genome stability at common fragile sites, which are often associated with the DNA breakpoints in cancer. Therefore, RAD52 has important recombination roles under special stress conditions in mammalian cells, and presents as a promising anti-cancer therapy target.
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19
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Min J, Wright WE, Shay JW. Clustered telomeres in phase-separated nuclear condensates engage mitotic DNA synthesis through BLM and RAD52. Genes Dev 2019; 33:814-827. [PMID: 31171703 PMCID: PMC6601508 DOI: 10.1101/gad.324905.119] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/24/2019] [Indexed: 11/25/2022]
Abstract
Alternative lengthening of telomeres (ALT) is a telomerase-independent telomere maintenance mechanism that occurs in a subset of cancers. One of the hallmarks of ALT cancer is the excessively clustered telomeres in promyelocytic leukemia (PML) bodies, represented as large bright telomere foci. Here, we present a model system that generates telomere clustering in nuclear polySUMO (small ubiquitin-like modification)/polySIM (SUMO-interacting motif) condensates, analogous to PML bodies, and thus artificially engineered ALT-associated PML body (APB)-like condensates in vivo. We observed that the ALT-like phenotypes (i.e., a small fraction of heterogeneous telomere lengths and formation of C circles) are rapidly induced by introducing the APB-like condensates together with BLM through its helicase domain, accompanied by ssDNA generation and RPA accumulation at telomeres. Moreover, these events lead to mitotic DNA synthesis (MiDAS) at telomeres mediated by RAD52 through its highly conserved N-terminal domain. We propose that the clustering of large amounts of telomeres in human cancers promotes ALT that is mediated by MiDAS, analogous to Saccharomyces cerevisiae type II ALT survivors.
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Affiliation(s)
- Jaewon Min
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, USA
| | - Woodring E Wright
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, USA
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, USA
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20
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Alnafakh RAA, Adishesh M, Button L, Saretzki G, Hapangama DK. Telomerase and Telomeres in Endometrial Cancer. Front Oncol 2019; 9:344. [PMID: 31157162 PMCID: PMC6533802 DOI: 10.3389/fonc.2019.00344] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/15/2019] [Indexed: 12/11/2022] Open
Abstract
Telomeres at the termini of human chromosomes are shortened with each round of cell division due to the “end replication problem” as well as oxidative stress. During carcinogenesis, cells acquire or retain mechanisms to maintain telomeres to avoid initiation of cellular senescence or apoptosis and halting cell division by critically short telomeres. The unique reverse transcriptase enzyme complex, telomerase, catalyzes the maintenance of telomeres but most human somatic cells do not have sufficient telomerase activity to prevent telomere shortening. Tissues with high and prolonged replicative potential demonstrate adequate cellular telomerase activity to prevent telomere erosion, and high telomerase activity appears to be a critical feature of most (80–90%) epithelial cancers, including endometrial cancer. Endometrial cancers regress in response to progesterone which is frequently used to treat advanced endometrial cancer. Endometrial telomerase is inhibited by progestogens and deciphering telomere and telomerase biology in endometrial cancer is therefore important, as targeting telomerase (a downstream target of progestogens) in endometrial cancer may provide novel and more effective therapeutic avenues. This review aims to examine the available evidence for the role and importance of telomere and telomerase biology in endometrial cancer.
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Affiliation(s)
- Rafah A A Alnafakh
- Liverpool Women's Hospital NHS Foundation Trust, Liverpool, United Kingdom.,Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Meera Adishesh
- Liverpool Women's Hospital NHS Foundation Trust, Liverpool, United Kingdom.,Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Lucy Button
- Liverpool Women's Hospital NHS Foundation Trust, Liverpool, United Kingdom.,Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Gabriele Saretzki
- The Ageing Biology Centre and Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Dharani K Hapangama
- Liverpool Women's Hospital NHS Foundation Trust, Liverpool, United Kingdom.,Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
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21
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Al Khleifat A, Iacoangeli A, Shatunov A, Fang T, Sproviero W, Jones AR, Opie-Martin S, Morrison KE, Shaw PJ, Shaw CE, Powell JF, Dobson R, Newhouse SJ, Al-Chalabi A. Telomere length is greater in ALS than in controls: a whole genome sequencing study. Amyotroph Lateral Scler Frontotemporal Degener 2019; 20:229-234. [PMID: 30931641 PMCID: PMC6567548 DOI: 10.1080/21678421.2019.1586951] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 02/06/2019] [Accepted: 02/10/2019] [Indexed: 12/30/2022]
Abstract
Background: Amyotrophic lateral sclerosis is a neurodegenerative disease of motor neurons resulting in progressive paralysis and death, typically within 3-5 years. Although the heritability of ALS is about 60%, only about 11% is explained by common gene variants, suggesting that other forms of genetic variation are important. Telomeres maintain DNA integrity during cellular replication and shorten naturally with age. Gender and age are risk factors for ALS and also associated with telomere length. We therefore investigated telomere length in ALS. Methods: We estimated telomere length by applying a bioinformatics analysis to whole genome sequence data of leukocyte-derived DNA from people with ALS and age and gender-matched matched controls in a UK population. We tested the association of telomere length with ALS and ALS survival. Results: There were 1241 people with ALS and 335 controls. The median age for ALS was 62.5 years and for controls, 60.1 years, with a male-female ratio of 62:38. Accounting for age and sex, there was a 9% increase of telomere length in ALS compared to matched controls. Those with longer telomeres had a 16% increase in median survival. Of nine SNPs associated with telomere length, two were also associated with ALS: rs8105767 near the ZNF208 gene (p = 1.29 × 10-4) and rs6772228 (p = 0.001), which is in an intron for the PXK gene. Conclusions: Longer telomeres in leukocyte-derived DNA are associated with ALS, and with increased survival in those with ALS.
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Affiliation(s)
- Ahmad Al Khleifat
- Department of Basic and Clinical Neuroscience, King’s College London, Maurice Wohl Clinical Neuroscience Institute, London, UK
| | - Alfredo Iacoangeli
- Department of Basic and Clinical Neuroscience, King’s College London, Maurice Wohl Clinical Neuroscience Institute, London, UK
- Department of Biostatistics and Health Informatics, King’s College London, London, UK
| | - Aleksey Shatunov
- Department of Basic and Clinical Neuroscience, King’s College London, Maurice Wohl Clinical Neuroscience Institute, London, UK
| | - Ton Fang
- Department of Basic and Clinical Neuroscience, King’s College London, Maurice Wohl Clinical Neuroscience Institute, London, UK
| | - William Sproviero
- Department of Basic and Clinical Neuroscience, King’s College London, Maurice Wohl Clinical Neuroscience Institute, London, UK
| | - Ashley R. Jones
- Department of Basic and Clinical Neuroscience, King’s College London, Maurice Wohl Clinical Neuroscience Institute, London, UK
| | - Sarah Opie-Martin
- Department of Basic and Clinical Neuroscience, King’s College London, Maurice Wohl Clinical Neuroscience Institute, London, UK
| | - Karen E. Morrison
- Faculty of Medicine, University of Southampton, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Pamela J. Shaw
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Christopher E. Shaw
- Department of Basic and Clinical Neuroscience, King’s College London, Maurice Wohl Clinical Neuroscience Institute, London, UK
- King’s College Hospital, London, UK
- Psychology and Neuroscience, United Kingdom Dementia Research Institute, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, King’s College London, London, UK, and
| | - John F. Powell
- Department of Basic and Clinical Neuroscience, King’s College London, Maurice Wohl Clinical Neuroscience Institute, London, UK
| | - Richard Dobson
- Department of Biostatistics and Health Informatics, King’s College London, London, UK
- Farr Institute of Health Informatics Research, UCL Institute of Health Informatics, University College London, London, UK
| | - Steven J. Newhouse
- Department of Biostatistics and Health Informatics, King’s College London, London, UK
- Farr Institute of Health Informatics Research, UCL Institute of Health Informatics, University College London, London, UK
| | - Ammar Al-Chalabi
- Department of Basic and Clinical Neuroscience, King’s College London, Maurice Wohl Clinical Neuroscience Institute, London, UK
- King’s College Hospital, London, UK
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22
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Wang F, Cheng Y, Zhang C, Chang G, Geng X. A novel antisense oligonucleotide anchored on the intronic splicing enhancer of hTERT pre-mRNA inhibits telomerase activity and induces apoptosis in glioma cells. J Neurooncol 2019; 143:57-68. [PMID: 30887243 DOI: 10.1007/s11060-019-03150-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Accepted: 03/11/2019] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Alternative splicing of hTERT pre-mRNA is an important step in the regulation of telomerase activity, but the regulation mechanisms and functions remain unclear. METHODS RT-PCR analysis was used to detect hTERT splicing in glioma cell lines and brain tissues. TRAP assay was used to detect the telomerase activity. Then, we designed and synthesized 2'-O-methyl-RNA phosphorothioate AONs and transfected them into glioma cells to detect the changes in telomerase activity. MTT assay, plate colony formation assay, western blotting and Annexin V/PI assay were used to detect cell proliferation and apoptosis. At last, bioinformatics analyses were used to predict the expression and function of splicing protein SRSF2 in gliomas. RESULTS hTERT splicing occurs both in glioma cell lines and glioma patients' tissues. The telomerase activity was related to the expression level of the full-length hTERT, rather than the total hTERT transcript level. AON-Ex726 was complementary to the sequence of the intronic splicing enhancer (ISE) in intron six, and significantly altered the splicing pattern of hTERT pre-mRNA, reducing the expression level of the full-length hTERT mRNA and increasing the expression level of the -β hTERT mRNA. After transfection with AON-Ex726, the level of apoptosis was increased, while telomerase activity and cell proliferation were significantly decreased. By bioinformatic predictions, we found the AON-Ex726 anchoring sequence in ISE overlaps the binding site of SRSF2 protein, which is up-regulated during the development of gliomas. CONCLUSIONS Our findings provided new targets and important clues for the gene therapy of gliomas by regulating the alternative splicing pattern of hTERT pre-mRNA.
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Affiliation(s)
- Fei Wang
- Department of Neurology, General Hospital, Tianjin Medical University, Tianjin, 300052, China
| | - Yajing Cheng
- Department of Neurology, General Hospital, Tianjin Medical University, Tianjin, 300052, China
| | - Chi Zhang
- Department of Neurology, General Hospital, Tianjin Medical University, Tianjin, 300052, China
| | - Guangming Chang
- Department of Clinical Laboratory, General Hospital, Tianjin Medical University, Tianjin, 300052, China
| | - Xin Geng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, 22nd Qixiangtai Road, Tianjin, 300070, China.
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Brane AC, Tollefsbol TO. Targeting Telomeres and Telomerase: Studies in Aging and Disease Utilizing CRISPR/Cas9 Technology. Cells 2019; 8:E186. [PMID: 30795542 PMCID: PMC6406488 DOI: 10.3390/cells8020186] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/14/2019] [Accepted: 02/20/2019] [Indexed: 12/11/2022] Open
Abstract
Telomeres and telomerase provide a unique and important avenue of study in improving both life expectancy and quality of life due to their close association with aging and disease. While major advances in our understanding of these two biological mediators have characterized the last two decades, previous studies have been limited by the inability to affect change in real time within living cells. The last three years, however, have witnessed a huge step forward to overcome this limitation. The advent of the clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR/Cas) system has led to a wide array of targeted genetic studies that are already being employed to modify telomeres and telomerase, as well as the genes that affect them. In this review, we analyze studies utilizing the technology to target and modify telomeres, telomerase, and their closely associated genes. We also discuss how these studies can provide insight into the biology and mechanisms that underlie aging, cancer, and other diseases.
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Affiliation(s)
- Andrew C Brane
- Department of Biology, University of Alabama at Birmingham, 1300 University Boulevard, Birmingham, AL 35294, USA.
| | - Trygve O Tollefsbol
- Department of Biology, University of Alabama at Birmingham, 1300 University Boulevard, Birmingham, AL 35294, USA.
- Comprehensive Center for Healthy Aging, University of Alabama Birmingham, 1530 3rd Avenue South, Birmingham, AL 35294, USA.
- Comprehensive Cancer Center, University of Alabama Birmingham, 1802 6th Avenue South, Birmingham, AL 35294, USA.
- Nutrition Obesity Research Center, University of Alabama Birmingham, 1675 University Boulevard, Birmingham, AL 35294, USA.
- Comprehensive Diabetes Center, University of Alabama Birmingham, 1825 University Boulevard, Birmingham, AL 35294, USA.
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24
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Zhang T, Zhang Z, Shengzhao G, Li X, Liu H, Zhao Y. Strand break-induced replication fork collapse leads to C-circles, C-overhangs and telomeric recombination. PLoS Genet 2019; 15:e1007925. [PMID: 30716077 PMCID: PMC6382176 DOI: 10.1371/journal.pgen.1007925] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 02/20/2019] [Accepted: 01/01/2019] [Indexed: 12/16/2022] Open
Abstract
Telomerase-independent ALT (alternative lengthening of telomeres) cells are characterized by high frequency of telomeric homologous recombination (HR), C-rich extrachromosomal circles (C-circles) and C-rich terminal 5' overhangs (C-overhangs). However, underlying mechanism is poorly understood. Here, we show that both C-circle and C-overhang form when replication fork collapse is induced by strand break at telomeres. We find that endogenous DNA break predominantly occur on C-rich strand of telomeres in ALT cells, resulting in high frequency of replication fork collapse. While collapsed forks could be rescued by replication fork regression leading to telomeric homologous recombination, those unresolved are converted to C-circles and C-overhang at lagging and leading synthesized strand, respectively. Meanwhile, multiple hallmarks of ALT are provoked, suggesting that strand break-induced replication stress underlies ALT. These findings provide a molecular basis underlying telomeric HR and biogenesis of C-circle and C-overhang, thus implicating the specific mechanism to resolve strand break-induced replication defect at telomeres in ALT cells. 10 to 15% human cancers utilize telomerase-independent alternative lengthening of telomeres (ALT) to maintain their telomere length. Unexpectedly, we find that endogenous C-strand breaks predominantly exist in telomeres of ALT cells, which induce high frequency of replication fork collapse. While collapsed fork triggers fork regression machinery to restart the replication, leading to telomeric homologous recombination; those unresolved are converted to C-circle and C-overhang. These findings suggest that the formation of C-circle and C-overhang represents a unique manner for ALT cells to prevent chromosome instability induced by replication defect at telomeres. Moreover, multiple hallmarks of ALT are provoked during this process, demonstrating that DNA strand break at telomeres underlies ALT mechanism.
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Affiliation(s)
- Tianpeng Zhang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China
| | - Zepeng Zhang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China
| | - Gong Shengzhao
- School of Chemical Engineering and Technology, Guangdong Engineering Technical Research Center for Green Household Chemicals, Guangdong Industry Technical College, Guangzhou, P.R.China
| | - Xiaocui Li
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China
| | - Haiying Liu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China
| | - Yong Zhao
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China
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25
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Abstract
The maintenance of genome stability in eukaryotic cells relies on accurate and efficient replication along each chromosome following every cell division. The terminal position, repetitive sequence, and structural complexities of the telomeric DNA make the telomere an inherently difficult region to replicate within the genome. Thus, despite functioning to protect genome stability mammalian telomeres are also a source of replication stress and have been recognized as common fragile sites within the genome. Telomere fragility is exacerbated at telomeres that rely on the Alternative Lengthening of Telomeres (ALT) pathway. Like common fragile sites, ALT telomeres are prone to chromosome breaks and are frequent sites of recombination suggesting that ALT telomeres are subjected to chronic replication stress. Here, we will review the features of telomeric DNA that challenge the replication machinery and also how the cell overcomes these challenges to maintain telomere stability and ensure the faithful duplication of the human genome.
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Affiliation(s)
- Emily Mason-Osann
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
- Department of Medicine, Cancer Center, Boston University School of Medicine, Boston, MA, USA
| | - Himabindu Gali
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
- Department of Medicine, Cancer Center, Boston University School of Medicine, Boston, MA, USA
| | - Rachel Litman Flynn
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA.
- Department of Medicine, Cancer Center, Boston University School of Medicine, Boston, MA, USA.
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26
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da Silva MS, Hovel-Miner GA, Briggs EM, Elias MC, McCulloch R. Evaluation of mechanisms that may generate DNA lesions triggering antigenic variation in African trypanosomes. PLoS Pathog 2018; 14:e1007321. [PMID: 30440029 PMCID: PMC6237402 DOI: 10.1371/journal.ppat.1007321] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Antigenic variation by variant surface glycoprotein (VSG) coat switching in African trypanosomes is one of the most elaborate immune evasion strategies found among pathogens. Changes in the identity of the transcribed VSG gene, which is always flanked by 70-bp and telomeric repeats, can be achieved either by transcriptional or DNA recombination mechanisms. The major route of VSG switching is DNA recombination, which occurs in the bloodstream VSG expression site (ES), a multigenic site transcribed by RNA polymerase I. Recombinogenic VSG switching is frequently catalyzed by homologous recombination (HR), a reaction normally triggered by DNA breaks. However, a clear understanding of how such breaks arise-including whether there is a dedicated and ES-focused mechanism-is lacking. Here, we synthesize data emerging from recent studies that have proposed a range of mechanisms that could generate these breaks: action of a nuclease or nucleases; repetitive DNA, most notably the 70-bp repeats, providing an intra-ES source of instability; DNA breaks derived from the VSG-adjacent telomere; DNA breaks arising from high transcription levels at the active ES; and DNA lesions arising from replication-transcription conflicts in the ES. We discuss the evidence that underpins these switch-initiation models and consider what features and mechanisms might be shared or might allow the models to be tested further. Evaluation of all these models highlights that we still have much to learn about the earliest acting step in VSG switching, which may have the greatest potential for therapeutic intervention in order to undermine the key reaction used by trypanosomes for their survival and propagation in the mammalian host.
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Affiliation(s)
- Marcelo Santos da Silva
- Laboratório Especial de Ciclo Celular, Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, Brazil
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Galadriel A. Hovel-Miner
- The George Washington University, Department of Microbiology Immunology, and Tropical Medicine, Washington, DC, United States of America
| | - Emma M. Briggs
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Maria Carolina Elias
- Laboratório Especial de Ciclo Celular, Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, Brazil
| | - Richard McCulloch
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
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27
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Haider S, Li P, Khiali S, Munnur D, Ramanathan A, Parkinson GN. Holliday Junctions Formed from Human Telomeric DNA. J Am Chem Soc 2018; 140:15366-15374. [PMID: 30376323 DOI: 10.1021/jacs.8b08699] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cells have evolved inherent mechanisms, like homologous recombination (HR), to repair damaged DNA. However, repairs at telomeres can lead to genomic instability, often associated with cancer. While most rapidly dividing cells employ telomerase, the others maintain telomere length through HR-dependent alternative lengthening of telomeres (ALT) pathways. Here we describe the crystal structures of Holliday junction intermediates of the HR-dependent ALT mechanism. Using an extended human telomeric repeat, we also report the crystal structure of two Holliday junctions in close proximity, which associate together through strand exchange to form a hemicatenated double Holliday junction. Our combined structural results demonstrate that ACC nucleotides in the C-rich lagging strand (5'-CTAACCCTAA-3') at the telomere repeat sequence constitute a conserved structural feature that constrains crossover geometry and is a preferred site for Holliday junction formation in telomeres.
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Affiliation(s)
- Shozeb Haider
- UCL School of Pharmacy , University College London , London WC1N 1AX , United Kingdom
| | - Pengfei Li
- UCL School of Pharmacy , University College London , London WC1N 1AX , United Kingdom
| | - Soraia Khiali
- UCL School of Pharmacy , University College London , London WC1N 1AX , United Kingdom
| | - Deeksha Munnur
- Dunn School of Pathology , University of Oxford , Oxford OX1 3RE , United Kingdom
| | - Arvind Ramanathan
- Computational Science and Engineering Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37830 , United States
| | - Gary N Parkinson
- UCL School of Pharmacy , University College London , London WC1N 1AX , United Kingdom
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28
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Brosnan-Cashman JA, Yuan M, Graham MK, Rizzo AJ, Myers KM, Davis C, Zhang R, Esopi DM, Raabe EH, Eberhart CG, Heaphy CM, Meeker AK. ATRX loss induces multiple hallmarks of the alternative lengthening of telomeres (ALT) phenotype in human glioma cell lines in a cell line-specific manner. PLoS One 2018; 13:e0204159. [PMID: 30226859 PMCID: PMC6143253 DOI: 10.1371/journal.pone.0204159] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 09/03/2018] [Indexed: 12/05/2022] Open
Abstract
Cancers must maintain their telomeres at lengths sufficient for cell survival. In several cancer subtypes, a recombination-like mechanism termed alternative lengthening of telomeres (ALT), is frequently used for telomere length maintenance. Cancers utilizing ALT often have lost functional ATRX, a chromatin remodeling protein, through mutation or deletion, thereby strongly implicating ATRX as an ALT suppressor. Herein, we have generated functional ATRX knockouts in four telomerase-positive, ALT-negative human glioma cell lines: MOG-G-UVW, SF188, U-251 and UW479. After loss of ATRX, two of the four cell lines (U-251 and UW479) show multiple characteristics of ALT-positive cells, including ultrabright telomeric DNA foci, ALT-associated PML bodies, and c-circles. However, telomerase activity and overall telomere length heterogeneity are unaffected after ATRX loss, regardless of cellular context. The two cell lines that showed ALT hallmarks after complete ATRX loss also did so upon ATRX depletion via shRNA-mediated knockdown. These results suggest that other genomic or epigenetic events, in addition to ATRX loss, are necessary for the induction of ALT in human cancer.
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Affiliation(s)
| | - Ming Yuan
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Mindy K. Graham
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Anthony J. Rizzo
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Kaylar M. Myers
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Christine Davis
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Rebecca Zhang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - David M. Esopi
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Eric H. Raabe
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- Department of Pediatric Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Charles G. Eberhart
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Christopher M. Heaphy
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Alan K. Meeker
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
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29
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Pompili L, Leonetti C, Biroccio A, Salvati E. Diagnosis and treatment of ALT tumors: is Trabectedin a new therapeutic option? JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2017; 36:189. [PMID: 29273061 PMCID: PMC5741932 DOI: 10.1186/s13046-017-0657-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 12/01/2017] [Indexed: 12/22/2022]
Abstract
Telomeres are specialized nucleoprotein structures responsible for protecting chromosome ends in order to prevent the loss of genomic information. Telomere maintenance is required for achieving immortality by neoplastic cells. While most cancer cells rely on telomerase re-activation for linear chromosome maintenance and sustained proliferation, a significant population of cancers (10-15%) employs telomerase-independent strategies, collectively referred to as Alternative Lengthening of Telomeres (ALT). ALT mechanisms involve different types of homology-directed telomere recombination and synthesis. These processes are facilitated by loss of the ATRX or DAXX chromatin-remodeling factors and by abnormalities of the telomere nucleoprotein architecture. Although the functional consequences of telomerase and ALT up-regulation are similar in that they both prevent overall telomere shortening in tumors, these telomere maintenance mechanisms (TMMs) differ in several aspects which may account for their differential prognostic significance and response to therapy in various tumor types. Therefore, reliable methods for detecting telomerase activity and ALT are likely to become an important pre-requisite for the use of treatments targeting one or other of these mechanisms. However, the question whether ALT presence can confer sensitivity to rationally designed anti-cancer therapies is still open. Here we review the latest discoveries in terms of mechanisms of ALT activation and maintenance in human tumors, methods for ALT identification in cell lines and human tissues and biomarkers validation. Then, original results on sensitivity to rational based pre-clinical and clinical anti-tumor drugs in ALT vs hTERT positive cells will be presented.
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Affiliation(s)
- Luca Pompili
- UOSD SAFU, Regina Elena National Cancer Institute, Rome, Italy.,University of Tuscia, Viterbo, Italy
| | - Carlo Leonetti
- UOSD SAFU, Regina Elena National Cancer Institute, Rome, Italy
| | - Annamaria Biroccio
- Oncogenomic and Epigenetic Unit, Regina Elena National Cancer Institute, Via Elio Chianesi, 53 -, 00144, Rome, Italy
| | - Erica Salvati
- Oncogenomic and Epigenetic Unit, Regina Elena National Cancer Institute, Via Elio Chianesi, 53 -, 00144, Rome, Italy.
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30
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Lai TP, Zhang N, Noh J, Mender I, Tedone E, Huang E, Wright WE, Danuser G, Shay JW. A method for measuring the distribution of the shortest telomeres in cells and tissues. Nat Commun 2017; 8:1356. [PMID: 29116081 PMCID: PMC5676791 DOI: 10.1038/s41467-017-01291-z] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 09/07/2017] [Indexed: 01/23/2023] Open
Abstract
Improved methods to measure the shortest (not just average) telomere lengths (TLs) are needed. We developed Telomere Shortest Length Assay (TeSLA), a technique that detects telomeres from all chromosome ends from <1 kb to 18 kb using small amounts of input DNA. TeSLA improves the specificity and efficiency of TL measurements that is facilitated by user friendly image-processing software to automatically detect and annotate band sizes, calculate average TL, as well as the percent of the shortest telomeres. Compared with other TL measurement methods, TeSLA provides more information about the shortest telomeres. The length of telomeres was measured longitudinally in peripheral blood mononuclear cells during human aging, in tissues during colon cancer progression, in telomere-related diseases such as idiopathic pulmonary fibrosis, as well as in mice and other organisms. The results indicate that TeSLA is a robust method that provides a better understanding of the shortest length of telomeres. Short telomeres are a hallmark of senescence and can result in genomic instability as well as cancer progression. Here, the authors present TeSLA, a technique to accurately detect telomeres under 1 kb in length.
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Affiliation(s)
- Tsung-Po Lai
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Ning Zhang
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA.,Department of Bioinformatics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Jungsik Noh
- Department of Bioinformatics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Ilgen Mender
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Enzo Tedone
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Ejun Huang
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Woodring E Wright
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Gaudenz Danuser
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA.,Department of Bioinformatics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA.
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31
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Alternative Lengthening of Telomeres Mediated by Mitotic DNA Synthesis Engages Break-Induced Replication Processes. Mol Cell Biol 2017; 37:MCB.00226-17. [PMID: 28760773 DOI: 10.1128/mcb.00226-17] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 07/20/2017] [Indexed: 01/05/2023] Open
Abstract
Alternative lengthening of telomeres (ALT) is a telomerase-independent telomere maintenance mechanism that occurs in a subset of cancers. By analyzing telomerase-positive cells and their human TERC knockout-derived ALT human cell lines, we show that ALT cells harbor more fragile telomeres representing telomere replication problems. ALT-associated replication defects trigger mitotic DNA synthesis (MiDAS) at telomeres in a RAD52-dependent, but RAD51-independent, manner. Telomeric MiDAS is a conservative DNA synthesis process, potentially mediated by break-induced replication, similar to type II ALT survivors in Saccharomyces cerevisiae Replication stresses induced by ectopic oncogenic expression of cyclin E, G-quadruplexes, or R-loop formation facilitate the ALT pathway and lead to telomere clustering, a hallmark of ALT cancers. The TIMELESS/TIPIN complex suppresses telomere clustering and telomeric MiDAS, whereas the SMC5/6 complex promotes them. In summary, ALT cells exhibit more telomere replication defects that result in persistent DNA damage responses at telomeres, leading to the engagement of telomeric MiDAS (spontaneous mitotic telomere synthesis) that is triggered by DNA replication stress, a potential driver of genomic duplications in cancer.
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32
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Stabilization of Telomere G-Quadruplexes Interferes with Human Herpesvirus 6A Chromosomal Integration. J Virol 2017; 91:JVI.00402-17. [PMID: 28468887 DOI: 10.1128/jvi.00402-17] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 04/29/2017] [Indexed: 11/20/2022] Open
Abstract
Human herpesviruses 6A and 6B (HHV-6A/B) can integrate their genomes into the telomeres of human chromosomes using a mechanism that remains poorly understood. To achieve a better understanding of the HHV-6A/B integration mechanism, we made use of BRACO-19, a compound that stabilizes G-quadruplex secondary structures and prevents telomere elongation by the telomerase complex. First, we analyzed the folding of telomeric sequences into G-quadruplex structures and their binding to BRACO-19 using G-quadruplex-specific antibodies and surface plasmon resonance. Circular dichroism studies indicate that BRACO-19 modifies the conformation and greatly stabilizes the G-quadruplexes formed in G-rich telomeric DNA. Subsequently we assessed the effects of BRACO-19 on the HHV-6A initial phase of infection. Our results indicate that BRACO-19 does not affect entry of HHV-6A DNA into cells. We next investigated if stabilization of G-quadruplexes by BRACO-19 affected HHV-6A's ability to integrate its genome into host chromosomes. Incubation of telomerase-expressing cells with BRACO-19, such as HeLa and MCF-7, caused a significant reduction in the HHV-6A integration frequency (P < 0.002); in contrast, BRACO-19 had no effect on HHV-6 integration frequency in U2OS cells that lack telomerase activity and elongate their telomeres through alternative lengthening mechanisms. Our data suggest that the fluidity of telomeres is important for efficient chromosomal integration of HHV-6A and that interference with telomerase activity negatively affects the generation of cellular clones containing integrated HHV-6A.IMPORTANCE HHV-6A/B can integrate their genomes into the telomeres of infected cells. Telomeres consist of repeated hexanucleotides (TTAGGG) of various lengths (up to several kilobases) and end with a single-stranded 3' extension. To avoid recognition and induce a DNA damage response, the single-stranded overhang folds back on itself and forms a telomeric loop (T-loop) or adopts a tertiary structure, referred to as a G-quadruplex. In the current study, we have examined the effects of a G-quadruplex binding and stabilizing agent, BRACO-19, on HHV-6A chromosomal integration. By stabilizing G-quadruplex structures, BRACO-19 affects the ability of the telomerase complex to elongate telomeres. Our results indicate that BRACO-19 reduces the number of clones harboring integrated HHV-6A. This study is the first of its kind and suggests that telomerase activity is essential to restore a functional telomere of adequate length following HHV-6A integration.
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33
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Naderlinger E, Holzmann K. Epigenetic Regulation of Telomere Maintenance for Therapeutic Interventions in Gliomas. Genes (Basel) 2017; 8:E145. [PMID: 28513547 PMCID: PMC5448019 DOI: 10.3390/genes8050145] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/08/2017] [Accepted: 05/12/2017] [Indexed: 02/07/2023] Open
Abstract
High-grade astrocytoma of WHO grade 4 termed glioblastoma multiforme (GBM) is a common human brain tumor with poor patient outcome. Astrocytoma demonstrates two known telomere maintenance mechanisms (TMMs) based on telomerase activity (TA) and on alternative lengthening of telomeres (ALT). ALT is associated with lower tumor grades and better outcome. In contrast to ALT, regulation of TA in tumors by direct mutation and epigenetic activation of the hTERT promoter is well established. Here, we summarize the genetic background of TMMs in non-malignant cells and in cancer, in addition to clinical and pathological features of gliomas. Furthermore, we present new evidence for epigenetic mechanisms (EMs) involved in regulation of ALT and TA with special emphasis on human diffuse gliomas as potential therapeutic drug targets. We discuss the role of TMM associated telomeric chromatin factors such as DNA and histone modifying enzymes and non-coding RNAs including microRNAs and long telomeric TERRA transcripts.
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Affiliation(s)
- Elisabeth Naderlinger
- Institute of Cancer Research, Comprehensive Cancer Center, Medical University of Vienna, Borschkegasse 8a, Vienna 1090, Austria.
| | - Klaus Holzmann
- Institute of Cancer Research, Comprehensive Cancer Center, Medical University of Vienna, Borschkegasse 8a, Vienna 1090, Austria.
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