1
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Zhao R, Xu M, Yu X, Wondisford AR, Lackner RM, Salsman J, Dellaire G, Chenoweth DM, O'Sullivan RJ, Zhao X, Zhang H. SUMO promotes DNA repair protein collaboration to support alternative telomere lengthening in the absence of PML. Genes Dev 2024; 38:614-630. [PMID: 39038850 PMCID: PMC11368244 DOI: 10.1101/gad.351667.124] [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: 02/29/2024] [Accepted: 07/08/2024] [Indexed: 07/24/2024]
Abstract
The alternative lengthening of telomeres (ALT) pathway maintains telomere length in a significant fraction of cancers that are associated with poor clinical outcomes. A better understanding of ALT mechanisms is therefore necessary for developing new treatment strategies for ALT cancers. SUMO modification of telomere proteins contributes to the formation of ALT telomere-associated PML bodies (APBs), in which telomeres are clustered and DNA repair proteins are enriched to promote homology-directed telomere DNA synthesis in ALT. However, it is still unknown whether-and if so, how-SUMO supports ALT beyond APB formation. Here, we show that SUMO condensates that contain DNA repair proteins enable telomere maintenance in the absence of APBs. In PML knockout ALT cell lines that lack APBs, we found that SUMOylation is required for manifesting ALT features independent of PML and APBs. Chemically induced telomere targeting of SUMO produces condensate formation and ALT features in PML-null cells. This effect requires both SUMOylation and interactions between SUMO and SUMO interaction motifs (SIMs). Mechanistically, SUMO-induced effects are associated with the accumulation of DNA repair proteins, including Rad52, Rad51AP1, RPA, and BLM, at telomeres. Furthermore, Rad52 can undergo phase separation, enrich SUMO at telomeres, and promote telomere DNA synthesis in collaboration with the BLM helicase in a SUMO-dependent manner. Collectively, our findings suggest that SUMO condensate formation promotes collaboration among DNA repair factors to support ALT telomere maintenance without PML. Given the promising effects of SUMOylation inhibitors in cancer treatment, our findings suggest their potential use in perturbing telomere maintenance in ALT cancer cells.
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Affiliation(s)
- Rongwei Zhao
- Department of Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Meng Xu
- Department of Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Xiaoyang Yu
- Department of Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Anne R Wondisford
- Department of Pharmacology and Chemical Biology, University of Pittsburgh Medical Center Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
| | - Rachel M Lackner
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19014, USA
| | - Jayme Salsman
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Graham Dellaire
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - David M Chenoweth
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19014, USA
| | - Roderick J O'Sullivan
- Department of Pharmacology and Chemical Biology, University of Pittsburgh Medical Center Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Huaiying Zhang
- Department of Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA;
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2
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Downs JA, Gasser SM. Chromatin remodeling and spatial concerns in DNA double-strand break repair. Curr Opin Cell Biol 2024; 90:102405. [PMID: 39083951 DOI: 10.1016/j.ceb.2024.102405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 07/07/2024] [Accepted: 07/11/2024] [Indexed: 08/02/2024]
Abstract
The substrate for the repair of DNA damage in living cells is not DNA but chromatin. Chromatin bears a range of modifications, which in turn bind ligands that compact or open chromatin structure, and determine its spatial organization within the nucleus. In some cases, RNA in the form of RNA:DNA hybrids or R-loops modulates DNA accessibility. Each of these parameters can favor particular pathways of repair. Chromatin or nucleosome remodelers are key regulators of chromatin structure, and a number of remodeling complexes are implicated in DNA repair. We cover novel insights into the impact of chromatin structure, nuclear organization, R-loop formation, nuclear actin, and nucleosome remodelers in DNA double-strand break repair, focusing on factors that alter repair functional upon ablation.
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Affiliation(s)
- Jessica A Downs
- Epigenetics and Genome Stability Team, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - Susan M Gasser
- ISREC Foundation, and University of Lausanne, Agora Cancer Research Center, Rue du Bugnon 25a, 1005 Lausanne, Switzerland.
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3
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Panda S, Roychowdhury T, Dutta A, Chakraborty S, Das T, Chatterjee S. ALTering Cancer by Triggering Telomere Replication Stress through the Stabilization of Promoter G-Quadruplex in SMARCAL1. ACS Chem Biol 2024; 19:1433-1439. [PMID: 38959478 DOI: 10.1021/acschembio.4c00285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Most of the human cancers are dependent on telomerase to extend the telomeres. But ∼10% of all cancers use a telomerase-independent, homologous recombination mediated pathway called alternative lengthening of telomeres (ALT). Due to the poor prognosis, ALT status is not being considered yet in the diagnosis of cancer. No such specific treatment is available to date for ALT positive cancers. ALT positive cancers are dependent on replication stress to deploy DNA repair pathways to the telomeres to execute homologous recombination mediated telomere extension. SMARCAL1 (SWI/SNF related, matrix-associated, actin-dependent regulator of chromatin, subfamily A-like 1) is associated with the ALT telomeres to resolve replication stress thus providing telomere stability. Thus, the dependency on replication stress regulatory factors like SMARCAL1 made it a suitable therapeutic target for the treatment of ALT positive cancers. In this study, we found a significant downregulation of SMARCAL1 expression by stabilizing the G-quadruplex (G4) motif found in the promoter of SMARCAL1 by potent G4 stabilizers, like TMPyP4 and BRACO-19. SMARCAL1 downregulation led toward the increased localization of PML (promyelocytic leukemia) bodies in ALT telomeres and triggered the formation of APBs (ALT-associated promyelocytic leukemia bodies) in ALT positive cell lines, increasing telomere replication stress and DNA damage at a genomic level. Induction of replication stress and hyper-recombinogenic phenotype in ALT positive cells mediated by G4 stabilizing molecules already highlighted their possible application as a new therapeutic window to target ALT positive tumors. In accordance with this, our study will also provide a valuable insight toward the development of G4-based ALT therapeutics targeting SMARCAL1.
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Affiliation(s)
- Suman Panda
- Department of Biophysics, Bose Institute, EN 80, Sector V, Bidhan Nagar, Kolkata 700091 West Bengal, India
| | - Tanaya Roychowdhury
- Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, New York 10065, United States of America
| | - Anindya Dutta
- Department of Biophysics, Bose Institute, EN 80, Sector V, Bidhan Nagar, Kolkata 700091 West Bengal, India
| | - Sourio Chakraborty
- Division of Molecular Medicine, Centenary Campus, Bose Institute, P-1/12 C.I.T. Scheme VII-M, Kolkata 700054, India
| | - Tanya Das
- Division of Molecular Medicine, Centenary Campus, Bose Institute, P-1/12 C.I.T. Scheme VII-M, Kolkata 700054, India
| | - Subhrangsu Chatterjee
- Department of Biophysics, Bose Institute, EN 80, Sector V, Bidhan Nagar, Kolkata 700091 West Bengal, India
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4
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Gaela VM, Hsia HY, Joseph NA, Tzeng WY, Ting PC, Shen YL, Tsai CT, Boudier T, Chen LY. Orphan nuclear receptors-induced ALT-associated PML bodies are targets for ALT inhibition. Nucleic Acids Res 2024; 52:6472-6489. [PMID: 38752489 PMCID: PMC11194075 DOI: 10.1093/nar/gkae389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 04/23/2024] [Accepted: 05/08/2024] [Indexed: 06/25/2024] Open
Abstract
Orphan nuclear receptors (NRs), such as COUP-TF1, COUP-TF2, EAR2, TR2 and TR4, are implicated in telomerase-negative cancers that maintain their telomeres through the alternative lengthening of telomeres (ALT) mechanism. However, how telomere association of orphan NRs is involved in ALT activation remains unclear. Here, we demonstrate that telomeric tethering of orphan NRs in human fibroblasts initiates formation of ALT-associated PML bodies (APBs) and features of ALT activity, including ALT telomere DNA synthesis, telomere sister chromatid exchange, and telomeric C-circle generation, suggesting de novo ALT induction. Overexpression of orphan NRs exacerbates ALT phenotypes in ALT cells, while their depletion limits ALT. Orphan NRs initiate ALT via the zinc finger protein 827, suggesting the involvement of chromatin structure alterations for ALT activation. Furthermore, we found that orphan NRs and deficiency of the ALT suppressor ATRX-DAXX complex operate in concert to promote ALT activation. Moreover, PML depletion by gene knockout or arsenic trioxide treatment inhibited ALT induction in fibroblasts and ALT cancer cells, suggesting that APB formation underlies the orphan NR-induced ALT activation. Importantly, arsenic trioxide administration abolished APB formation and features of ALT activity in ALT cancer cell line-derived mouse xenografts, suggesting its potential for further therapeutic development to treat ALT cancers.
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Affiliation(s)
- Venus Marie Gaela
- Molecular and Cell Biology, Taiwan International Graduate Program, Academia Sinica and Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 11529, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Hsuan-Yu Hsia
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Nithila A Joseph
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Wan-Yi Tzeng
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
- Insitute of Molecular and Cellular Biology, National Taiwan University, Taipei 106319, Taiwan
| | - Pin-Chao Ting
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
- Department and Graduate Institute of Microbiology and Immunology, National Defense Medical Center, Taipei 11490, Taiwan
| | - Yi-Ling Shen
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Chia-Tsen Tsai
- Molecular and Cell Biology, Taiwan International Graduate Program, Academia Sinica and Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 11529, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Thomas Boudier
- CENTURI multi-engineering platform, Aix-Marseille Université, Marseille 13288, France
| | - Liuh-Yow Chen
- Molecular and Cell Biology, Taiwan International Graduate Program, Academia Sinica and Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 11529, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
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5
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Chu LX, Wang WJ, Gu XP, Wu P, Gao C, Zhang Q, Wu J, Jiang DW, Huang JQ, Ying XW, Shen JM, Jiang Y, Luo LH, Xu JP, Ying YB, Chen HM, Fang A, Feng ZY, An SH, Li XK, Wang ZG. Spatiotemporal multi-omics: exploring molecular landscapes in aging and regenerative medicine. Mil Med Res 2024; 11:31. [PMID: 38797843 PMCID: PMC11129507 DOI: 10.1186/s40779-024-00537-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 05/07/2024] [Indexed: 05/29/2024] Open
Abstract
Aging and regeneration represent complex biological phenomena that have long captivated the scientific community. To fully comprehend these processes, it is essential to investigate molecular dynamics through a lens that encompasses both spatial and temporal dimensions. Conventional omics methodologies, such as genomics and transcriptomics, have been instrumental in identifying critical molecular facets of aging and regeneration. However, these methods are somewhat limited, constrained by their spatial resolution and their lack of capacity to dynamically represent tissue alterations. The advent of emerging spatiotemporal multi-omics approaches, encompassing transcriptomics, proteomics, metabolomics, and epigenomics, furnishes comprehensive insights into these intricate molecular dynamics. These sophisticated techniques facilitate accurate delineation of molecular patterns across an array of cells, tissues, and organs, thereby offering an in-depth understanding of the fundamental mechanisms at play. This review meticulously examines the significance of spatiotemporal multi-omics in the realms of aging and regeneration research. It underscores how these methodologies augment our comprehension of molecular dynamics, cellular interactions, and signaling pathways. Initially, the review delineates the foundational principles underpinning these methods, followed by an evaluation of their recent applications within the field. The review ultimately concludes by addressing the prevailing challenges and projecting future advancements in the field. Indubitably, spatiotemporal multi-omics are instrumental in deciphering the complexities inherent in aging and regeneration, thus charting a course toward potential therapeutic innovations.
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Affiliation(s)
- Liu-Xi Chu
- Affiliated Cixi Hospital, Wenzhou Medical University, Ningbo, 315300, Zhejiang, China
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Wen-Jia Wang
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing, 210096, China
| | - Xin-Pei Gu
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Screening, Southern Medical University, Guangzhou, 510515, China
- Department of Human Anatomy, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, 271000, Shandong, China
| | - Ping Wu
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Chen Gao
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing, 210096, China
| | - Quan Zhang
- Integrative Muscle Biology Laboratory, Division of Regenerative and Rehabilitative Sciences, University of Tennessee Health Science Center, Memphis, TN, 38163, United States
| | - Jia Wu
- Key Laboratory for Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Da-Wei Jiang
- Affiliated Cixi Hospital, Wenzhou Medical University, Ningbo, 315300, Zhejiang, China
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Jun-Qing Huang
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
- Key Laboratory of Imaging Diagnosis and Minimally Invasive Intervention Research, Institute of Imaging Diagnosis and Minimally Invasive Intervention Research, the Fifth Affiliated Hospital of Wenzhou Medical University, Lishui Hospital of Zhejiang University, Lishui, 323000, Zhejiang, China
| | - Xin-Wang Ying
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Jia-Men Shen
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Yi Jiang
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Li-Hua Luo
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, 324025, Zhejiang, China
| | - Jun-Peng Xu
- Affiliated Cixi Hospital, Wenzhou Medical University, Ningbo, 315300, Zhejiang, China
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Yi-Bo Ying
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Hao-Man Chen
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Ao Fang
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Zun-Yong Feng
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.
- Departments of Diagnostic Radiology, Surgery, Chemical and Biomolecular Engineering, and Biomedical Engineering, Yong Loo Lin School of Medicine and College of Design and Engineering, National University of Singapore, Singapore, 119074, Singapore.
- Clinical Imaging Research Centre, Centre for Translational Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117599, Singapore.
- Nanomedicine Translational Research Program, NUS Center for Nanomedicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research (A*STAR), Singapore, 138673, Singapore.
| | - Shu-Hong An
- Department of Human Anatomy, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, 271000, Shandong, China.
| | - Xiao-Kun Li
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.
| | - Zhou-Guang Wang
- Affiliated Cixi Hospital, Wenzhou Medical University, Ningbo, 315300, Zhejiang, China.
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.
- National Key Laboratory of Macromolecular Drug Development and Manufacturing, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.
- Key Laboratory of Imaging Diagnosis and Minimally Invasive Intervention Research, Institute of Imaging Diagnosis and Minimally Invasive Intervention Research, the Fifth Affiliated Hospital of Wenzhou Medical University, Lishui Hospital of Zhejiang University, Lishui, 323000, Zhejiang, China.
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6
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Zhao R, Xu M, Wondisford AR, Lackner RM, Salsman J, Dellaire G, Chenoweth DM, O’Sullivan RJ, Zhao X, Zhang H. SUMO Promotes DNA Repair Protein Collaboration to Support Alterative Telomere Lengthening in the Absence of PML. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.29.582813. [PMID: 38463993 PMCID: PMC10925274 DOI: 10.1101/2024.02.29.582813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Alternative lengthening of telomeres (ALT) pathway maintains telomeres in a significant fraction of cancers associated with poor clinical outcomes. A better understanding of ALT mechanisms can provide a basis for developing new treatment strategies for ALT cancers. SUMO modification of telomere proteins plays a critical role in the formation of ALT telomere-associated PML bodies (APBs), where telomeres are clustered and DNA repair proteins are enriched to promote homology-directed telomere DNA synthesis in ALT. However, whether and how SUMO contributes to ALT beyond APB formation remains elusive. Here, we report that SUMO promotes collaboration among DNA repair proteins to achieve APB-independent telomere maintenance. By using ALT cancer cells with PML protein knocked out and thus devoid of APBs, we show that sumoylation is required for manifesting ALT features, including telomere clustering and telomeric DNA synthesis, independent of PML and APBs. Further, small molecule-induced telomere targeting of SUMO produces signatures of phase separation and ALT features in PML null cells in a manner depending on both sumoylation and SUMO interaction with SUMO interaction motifs (SIMs). Mechanistically, SUMO-induced effects are linked to the enrichment of DNA repair proteins, including Rad52, Rad51AP1, and BLM, to the SUMO-containing telomere foci. Finally, we find that Rad52 can undergo phase separation, enrich SUMO on telomeres, and promote telomere DNA synthesis in collaboration with the BLM helicase in a SUMO-dependent manner. Collectively, our findings suggest that, in addition to forming APBs, SUMO also promotes collaboration among DNA repair proteins to support telomere maintenance in ALT cells. Given the promising effects of sumoylation inhibitors in cancer treatment, our findings suggest their potential use in perturbing telomere maintenance in ALT cancer cells.
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Affiliation(s)
- Rongwei Zhao
- Department of Biology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Meng Xu
- Department of Biology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Anne R. Wondisford
- Department of Pharmacology and Chemical Biology, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Rachel M. Lackner
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19014 , USA
| | - Jayme Salsman
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Graham Dellaire
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | - David M. Chenoweth
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19014 , USA
| | - Roderick J. O’Sullivan
- Department of Pharmacology and Chemical Biology, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Huaiying Zhang
- Department of Biology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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7
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Rai R, Sodeinde T, Boston A, Chang S. Telomeres cooperate with the nuclear envelope to maintain genome stability. Bioessays 2024; 46:e2300184. [PMID: 38047499 DOI: 10.1002/bies.202300184] [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: 09/25/2023] [Revised: 11/12/2023] [Accepted: 11/14/2023] [Indexed: 12/05/2023]
Abstract
Mammalian telomeres have evolved safeguards to prevent their recognition as DNA double-stranded breaks by suppressing the activation of various DNA sensing and repair proteins. We have shown that the telomere-binding proteins TRF2 and RAP1 cooperate to prevent telomeres from undergoing aberrant homology-directed recombination by mediating t-loop protection. Our recent findings also suggest that mammalian telomere-binding proteins interact with the nuclear envelope to maintain chromosome stability. RAP1 interacts with nuclear lamins through KU70/KU80, and disruption of RAP1 and TRF2 function result in nuclear envelope rupture, promoting telomere-telomere recombination to form structures termed ultrabright telomeres. In this review, we discuss the importance of the interactions between shelterin components and the nuclear envelope to maintain telomere homeostasis and genome stability.
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Affiliation(s)
- Rekha Rai
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Tori Sodeinde
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Ava Boston
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sandy Chang
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut, USA
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8
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Spegg V, Altmeyer M. Genome maintenance meets mechanobiology. Chromosoma 2024; 133:15-36. [PMID: 37581649 PMCID: PMC10904543 DOI: 10.1007/s00412-023-00807-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/20/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023]
Abstract
Genome stability is key for healthy cells in healthy organisms, and deregulated maintenance of genome integrity is a hallmark of aging and of age-associated diseases including cancer and neurodegeneration. To maintain a stable genome, genome surveillance and repair pathways are closely intertwined with cell cycle regulation and with DNA transactions that occur during transcription and DNA replication. Coordination of these processes across different time and length scales involves dynamic changes of chromatin topology, clustering of fragile genomic regions and repair factors into nuclear repair centers, mobilization of the nuclear cytoskeleton, and activation of cell cycle checkpoints. Here, we provide a general overview of cell cycle regulation and of the processes involved in genome duplication in human cells, followed by an introduction to replication stress and to the cellular responses elicited by perturbed DNA synthesis. We discuss fragile genomic regions that experience high levels of replication stress, with a particular focus on telomere fragility caused by replication stress at the ends of linear chromosomes. Using alternative lengthening of telomeres (ALT) in cancer cells and ALT-associated PML bodies (APBs) as examples of replication stress-associated clustered DNA damage, we discuss compartmentalization of DNA repair reactions and the role of protein properties implicated in phase separation. Finally, we highlight emerging connections between DNA repair and mechanobiology and discuss how biomolecular condensates, components of the nuclear cytoskeleton, and interfaces between membrane-bound organelles and membraneless macromolecular condensates may cooperate to coordinate genome maintenance in space and time.
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Affiliation(s)
- Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
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9
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Zhang Y, Hou K, Tong J, Zhang H, Xiong M, Liu J, Jia S. The Altered Functions of Shelterin Components in ALT Cells. Int J Mol Sci 2023; 24:16830. [PMID: 38069153 PMCID: PMC10706665 DOI: 10.3390/ijms242316830] [Citation(s) in RCA: 3] [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: 10/30/2023] [Revised: 11/23/2023] [Accepted: 11/24/2023] [Indexed: 12/18/2023] Open
Abstract
Telomeres are nucleoprotein complexes that cap the ends of eukaryotic linear chromosomes. Telomeric DNA is bound by shelterin protein complex to prevent telomeric chromosome ends from being recognized as damaged sites for abnormal repair. To overcome the end replication problem, cancer cells mostly preserve their telomeres by reactivating telomerase, but a minority (10-15%) of cancer cells use a homologous recombination-based pathway called alternative lengthening of telomeres (ALT). Recent studies have found that shelterin components play an important role in the ALT mechanism. The binding of TRF1, TRF2, and RAP1 to telomeres attenuates ALT activation, while the maintenance of ALT telomere requires TRF1 and TRF2. POT1 and TPP1 can also influence the occurrence of ALT. The elucidation of how shelterin regulates the initiation of ALT remains elusive. This review presents a comprehensive overview of the current findings on the regulation of ALT by shelterin components, aiming to enhance the insight into the altered functions of shelterin components in ALT cells and to identify potential targets for the treatment of ALT tumor cells.
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Affiliation(s)
| | | | | | | | | | - Jing Liu
- Laboratory of Molecular Genetics of Aging and Tumor, Medical School, Kunming University of Science and Technology, 727 Jing Ming Nan Road, Kunming 650500, China; (Y.Z.); (K.H.); (J.T.); (H.Z.); (M.X.)
| | - Shuting Jia
- Laboratory of Molecular Genetics of Aging and Tumor, Medical School, Kunming University of Science and Technology, 727 Jing Ming Nan Road, Kunming 650500, China; (Y.Z.); (K.H.); (J.T.); (H.Z.); (M.X.)
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10
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Chojak R, Fares J, Petrosyan E, Lesniak MS. Cellular senescence in glioma. J Neurooncol 2023; 164:11-29. [PMID: 37458855 DOI: 10.1007/s11060-023-04387-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 07/01/2023] [Indexed: 08/29/2023]
Abstract
INTRODUCTION Glioma is the most common primary brain tumor and is often associated with treatment resistance and poor prognosis. Standard treatment typically involves radiotherapy and temozolomide-based chemotherapy, both of which induce cellular senescence-a tumor suppression mechanism. DISCUSSION Gliomas employ various mechanisms to bypass or escape senescence and remain in a proliferative state. Importantly, senescent cells remain viable and secrete a large number of factors collectively known as the senescence-associated secretory phenotype (SASP) that, paradoxically, also have pro-tumorigenic effects. Furthermore, senescent cells may represent one form of tumor dormancy and play a role in glioma recurrence and progression. CONCLUSION In this article, we delineate an overview of senescence in the context of gliomas, including the mechanisms that lead to senescence induction, bypass, and escape. Furthermore, we examine the role of senescent cells in the tumor microenvironment and their role in tumor progression and recurrence. Additionally, we highlight potential therapeutic opportunities for targeting senescence in glioma.
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Affiliation(s)
- Rafał Chojak
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, 676 N. St Clair Street, Suite 2210, Chicago, IL, 60611, USA
- Northwestern Medicine Malnati Brain Tumor Institute, Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jawad Fares
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, 676 N. St Clair Street, Suite 2210, Chicago, IL, 60611, USA
- Northwestern Medicine Malnati Brain Tumor Institute, Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Edgar Petrosyan
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, 676 N. St Clair Street, Suite 2210, Chicago, IL, 60611, USA
- Northwestern Medicine Malnati Brain Tumor Institute, Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Maciej S Lesniak
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, 676 N. St Clair Street, Suite 2210, Chicago, IL, 60611, USA.
- Northwestern Medicine Malnati Brain Tumor Institute, Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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11
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Saha G, Roy S, Basu M, Ghosh MK. USP7 - a crucial regulator of cancer hallmarks. Biochim Biophys Acta Rev Cancer 2023; 1878:188903. [PMID: 37127084 DOI: 10.1016/j.bbcan.2023.188903] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 04/28/2023] [Accepted: 04/28/2023] [Indexed: 05/03/2023]
Abstract
Over the course of three decades of study, the deubiquitinase Herpesvirus associated Ubiquitin-Specific Protease/Ubiquitin-Specific Protease 7 (HAUSP/USP7) has gradually come to be recognized as a crucially important molecule in cellular physiology. The fact that USP7 is overexpressed in a number of cancers, including breast, prostate, colorectal, and lung cancers, supports the idea that USP7 is also an important regulator of tumorigenesis. In this review, we discuss USP7's function in relation to the cancer hallmarks described by Hanahan and Weinberg. This post-translational modifier can support increased proliferation, block unfavorable growth signals, stop cell death, and support an unstable cellular genome by manipulating key players in the pertinent signalling circuit. It is interesting to note that USP7 also aids in the stabilization of molecules that support angiogenesis and metastasis. Targeting USP7 has now emerged as a crucial component of USP7 research because pharmacological inhibition of USP7 supports p53-mediated cell cycle arrest and apoptosis. Efficacious USP7 inhibition is currently being investigated in both synthetic and natural compounds, but issues with selectivity and a lack of co-crystal structure have hindered USP7 inhibition from being tested in clinical settings. Moreover, the development of new, more effective USP7 inhibitors and their encouraging implications by numerous groups give us a glimmer of hope for USP7-targeting medications as effective substitutes for hazardous cancer chemotherapeutics.
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Affiliation(s)
- Gouranga Saha
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology (CSIR-IICB), TRUE Campus, CN-6, Sector-V, Salt Lake, Kolkata-700091 & 4, Raja S.C. Mullick Road, Jadavpur, Kolkata, PIN - 700032, India
| | - Srija Roy
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology (CSIR-IICB), TRUE Campus, CN-6, Sector-V, Salt Lake, Kolkata-700091 & 4, Raja S.C. Mullick Road, Jadavpur, Kolkata, PIN - 700032, India
| | - Malini Basu
- Department of Microbiology, Dhruba Chand Halder College, University of Calcutta, Kolkata, PIN - 743372, India
| | - Mrinal K Ghosh
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology (CSIR-IICB), TRUE Campus, CN-6, Sector-V, Salt Lake, Kolkata-700091 & 4, Raja S.C. Mullick Road, Jadavpur, Kolkata, PIN - 700032, India.
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12
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Broderick R, Cherdyntseva V, Nieminuszczy J, Dragona E, Kyriakaki M, Evmorfopoulou T, Gagos S, Niedzwiedz W. Pathway choice in the alternative telomere lengthening in neoplasia is dictated by replication fork processing mediated by EXD2's nuclease activity. Nat Commun 2023; 14:2428. [PMID: 37105990 PMCID: PMC10140042 DOI: 10.1038/s41467-023-38029-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
Telomerase-independent cancer proliferation via the alternative lengthening of telomeres (ALT) relies upon two distinct, largely uncharacterized, break-induced-replication (BIR) processes. How cancer cells initiate and regulate these terminal repair mechanisms is unknown. Here, we establish that the EXD2 nuclease is recruited to ALT telomeres to direct their maintenance. We demonstrate that EXD2 loss leads to telomere shortening, elevated telomeric sister chromatid exchanges, C-circle formation as well as BIR-mediated telomeric replication. We discover that EXD2 fork-processing activity triggers a switch between RAD52-dependent and -independent ALT-associated BIR. The latter is suppressed by EXD2 but depends specifically on the fork remodeler SMARCAL1 and the MUS81 nuclease. Thus, our findings suggest that processing of stalled replication forks orchestrates elongation pathway choice at ALT telomeres. Finally, we show that co-depletion of EXD2 with BLM, DNA2 or POLD3 confers synthetic lethality in ALT cells, identifying EXD2 as a potential druggable target for ALT-reliant cancers.
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Affiliation(s)
| | - Veronica Cherdyntseva
- Laboratory of Genetics, Center of Clinical Research, Experimental Surgery and Translational Research Biomedical Research Foundation Academy of Athens (BRFAA), Athens, Greece
| | | | - Eleni Dragona
- Laboratory of Genetics, Center of Clinical Research, Experimental Surgery and Translational Research Biomedical Research Foundation Academy of Athens (BRFAA), Athens, Greece
| | - Maria Kyriakaki
- Laboratory of Genetics, Center of Clinical Research, Experimental Surgery and Translational Research Biomedical Research Foundation Academy of Athens (BRFAA), Athens, Greece
| | - Theodora Evmorfopoulou
- Laboratory of Genetics, Center of Clinical Research, Experimental Surgery and Translational Research Biomedical Research Foundation Academy of Athens (BRFAA), Athens, Greece
| | - Sarantis Gagos
- Laboratory of Genetics, Center of Clinical Research, Experimental Surgery and Translational Research Biomedical Research Foundation Academy of Athens (BRFAA), Athens, Greece.
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13
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Kusuma FK, Prabhu A, Tieo G, Ahmed SM, Dakle P, Yong WK, Pathak E, Madan V, Jiang YY, Tam WL, Kappei D, Dröge P, Koeffler HP, Jeitany M. Signalling inhibition by ponatinib disrupts productive alternative lengthening of telomeres (ALT). Nat Commun 2023; 14:1919. [PMID: 37024489 PMCID: PMC10079688 DOI: 10.1038/s41467-023-37633-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 03/24/2023] [Indexed: 04/08/2023] Open
Abstract
Alternative lengthening of telomeres (ALT) supports telomere maintenance in 10-15% of cancers, thus representing a compelling target for therapy. By performing anti-cancer compound library screen on isogenic cell lines and using extrachromosomal telomeric C-circles, as a bona fide marker of ALT activity, we identify a receptor tyrosine kinase inhibitor ponatinib that deregulates ALT mechanisms, induces telomeric dysfunction, reduced ALT-associated telomere synthesis, and targets, in vivo, ALT-positive cells. Using RNA-sequencing and quantitative phosphoproteomic analyses, combined with C-circle level assessment, we find an ABL1-JNK-JUN signalling circuit to be inhibited by ponatinib and to have a role in suppressing telomeric C-circles. Furthermore, transcriptome and interactome analyses suggest a role of JUN in DNA damage repair. These results are corroborated by synergistic drug interactions between ponatinib and either DNA synthesis or repair inhibitors, such as triciribine. Taken together, we describe here a signalling pathway impacting ALT which can be targeted by a clinically approved drug.
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Affiliation(s)
- Frances Karla Kusuma
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Aishvaryaa Prabhu
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Galen Tieo
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Syed Moiz Ahmed
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Pushkar Dakle
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Wai Khang Yong
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Elina Pathak
- Genome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Vikas Madan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Yan Yi Jiang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, P. R. China
| | - Wai Leong Tam
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Genome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Dennis Kappei
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- NUS Center for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Peter Dröge
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - H Phillip Koeffler
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
- Cedars-Sinai Medical Center, Division of Hematology/Oncology, UCLA School of Medicine, Los Angeles, CA, USA
- Department of Hematology-Oncology, National University Cancer Institute of Singapore (NCIS), National University Hospital, Singapore, Singapore
| | - Maya Jeitany
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
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14
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Li F, Wang Y, Hwang I, Jang JY, Xu L, Deng Z, Yu EY, Cai Y, Wu C, Han Z, Huang YH, Huang X, Zhang L, Yao J, Lue NF, Lieberman PM, Ying H, Paik J, Zheng H. Histone demethylase KDM2A is a selective vulnerability of cancers relying on alternative telomere maintenance. Nat Commun 2023; 14:1756. [PMID: 36991019 PMCID: PMC10060224 DOI: 10.1038/s41467-023-37480-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 03/17/2023] [Indexed: 03/31/2023] Open
Abstract
Telomere length maintenance is essential for cellular immortalization and tumorigenesis. 5% - 10% of human cancers rely on a recombination-based mechanism termed alternative lengthening of telomeres (ALT) to sustain their replicative immortality, yet there are currently no targeted therapies. Through CRISPR/Cas9-based genetic screens in an ALT-immortalized isogenic cellular model, here we identify histone lysine demethylase KDM2A as a molecular vulnerability selectively for cells contingent on ALT-dependent telomere maintenance. Mechanistically, we demonstrate that KDM2A is required for dissolution of the ALT-specific telomere clusters following recombination-directed telomere DNA synthesis. We show that KDM2A promotes de-clustering of ALT multitelomeres through facilitating isopeptidase SENP6-mediated SUMO deconjugation at telomeres. Inactivation of KDM2A or SENP6 impairs post-recombination telomere de-SUMOylation and thus dissolution of ALT telomere clusters, leading to gross chromosome missegregation and mitotic cell death. These findings together establish KDM2A as a selective molecular vulnerability and a promising drug target for ALT-dependent cancers.
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Affiliation(s)
- Fei Li
- Department of Neurosurgery, Southwest Hospital, Chongqing, 400038, China
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Yizhe Wang
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Inah Hwang
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, 10065, USA
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Ja-Young Jang
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Libo Xu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
- Key Laboratory of Pathobiology, Ministry of Education, and Department of Pathophysiology, College of Basic Medical Sciences, Jilin University, Changchun, Jilin, China
| | - Zhong Deng
- The Wistar Institute, Philadelphia, PA, 19104, USA
| | - Eun Young Yu
- Department of Microbiology and Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Yiming Cai
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, 77030, USA
| | - Caizhi Wu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Zhenbo Han
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, 77030, USA
| | - Yu-Han Huang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Xiangao Huang
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Ling Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
- Key Laboratory of Pathobiology, Ministry of Education, and Department of Pathophysiology, College of Basic Medical Sciences, Jilin University, Changchun, Jilin, China
| | - Jun Yao
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, 77030, USA
| | - Neal F Lue
- Department of Microbiology and Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, New York, NY, 10065, USA
| | | | - Haoqiang Ying
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, 77030, USA
| | - Jihye Paik
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, 10065, USA.
| | - Hongwu Zheng
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, 10065, USA.
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15
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Clatterbuck Soper SF, Meltzer PS. ATRX/DAXX: Guarding the Genome against the Hazards of ALT. Genes (Basel) 2023; 14:genes14040790. [PMID: 37107548 PMCID: PMC10137841 DOI: 10.3390/genes14040790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023] Open
Abstract
Proliferating cells must enact a telomere maintenance mechanism to ensure genomic stability. In a subset of tumors, telomeres are maintained not by telomerase, but through a homologous recombination-based mechanism termed Alternative Lengthening of Telomeres or ALT. The ALT process is linked to mutations in the ATRX/DAXX/H3.3 histone chaperone complex. This complex is responsible for depositing non-replicative histone variant H3.3 at pericentric and telomeric heterochromatin but has also been found to have roles in ameliorating replication in repeat sequences and in promoting DNA repair. In this review, we will discuss ways in which ATRX/DAXX helps to protect the genome, and how loss of this complex allows ALT to take hold.
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16
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Histone demethylase KDM2A is a selective vulnerability of cancers relying on alternative telomere maintenance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.10.528023. [PMID: 36798426 PMCID: PMC9934630 DOI: 10.1101/2023.02.10.528023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Telomere length maintenance is essential for cellular immortalization and tumorigenesis. 5% - 10% of human cancers rely on a recombination-based mechanism termed alternative lengthening of telomeres (ALT) to sustain their replicative immortality, yet there are currently no targeted therapies. Through CRISPR/Cas9-based genetic screens in an ALT-immortalized isogenic cellular model, here we identify histone lysine demethylase KDM2A as a molecular vulnerability selectively for cells contingent on ALT-dependent telomere maintenance. Mechanistically, we demonstrate that KDM2A is required for dissolution of the ALT-specific telomere clusters following homology-directed telomere DNA synthesis. We show that KDM2A promotes de-clustering of ALT multitelomeres through facilitating isopeptidase SENP6-mediated SUMO deconjugation at telomeres. Inactivation of KDM2A or SENP6 impairs post-recombination telomere de-SUMOylation and thus dissolution of ALT telomere clusters, leading to gross chromosome missegregation and mitotic cell death. These findings together establish KDM2A as a selective molecular vulnerability and a promising drug target for ALT-dependent cancers.
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17
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Sun H, Chen G, Guo B, Lv S, Yuan G. Potential clinical treatment prospects behind the molecular mechanism of alternative lengthening of telomeres (ALT). J Cancer 2023; 14:417-433. [PMID: 36860927 PMCID: PMC9969575 DOI: 10.7150/jca.80097] [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: 10/22/2022] [Accepted: 12/25/2022] [Indexed: 02/04/2023] Open
Abstract
Normal somatic cells inevitably experience replicative stress and senescence during proliferation. Somatic cell carcinogenesis can be prevented in part by limiting the reproduction of damaged or old cells and removing them from the cell cycle [1, 2]. However, Cancer cells must overcome the issues of replication pressure and senescence as well as preserve telomere length in order to achieve immortality, in contrast to normal somatic cells [1, 2]. Although telomerase accounts for the bulk of telomere lengthening methods in human cancer cells, there is a non-negligible portion of telomere lengthening pathways that depend on alternative lengthening of telomeres (ALT) [3]. For the selection of novel possible therapeutic targets for ALT-related disorders, a thorough understanding of the molecular biology of these diseases is crucial [4]. The roles of ALT, typical ALT tumor cell traits, the pathophysiology and molecular mechanisms of ALT tumor disorders, such as adrenocortical carcinoma (ACC), are all summarized in this work. Additionally, this research compiles as many of its hypothetically viable but unproven treatment targets as it can (ALT-associated PML bodies (APB), etc.). This review is intended to contribute as much as possible to the development of research, while also trying to provide a partial information for prospective investigations on ALT pathways and associated diseases.
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Affiliation(s)
- Haolu Sun
- Department of Pathophysiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, 230011, China
| | - Guijuan Chen
- School of Environment and Chemical Engineering, Anhui Vocational and Technical College, Hefei, 230011, China
| | - Baochang Guo
- Rehabilitation Department of Traditional Chinese Medicine, 969 Hospital of the Joint Support Force of the Chinese People's Liberation Army, Hohhot, 010000, China
| | - Shushu Lv
- Department of Pathology, The First Affiliated Hospital of Huzhou University, Huzhou 313000, China
| | - Guojun Yuan
- School of Environment and Chemical Engineering, Anhui Vocational and Technical College, Hefei, 230011, China
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18
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Ren J, Zhang Z, Zong Z, Zhang L, Zhou F. Emerging Implications of Phase Separation in Cancer. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202855. [PMID: 36117111 PMCID: PMC9631093 DOI: 10.1002/advs.202202855] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 08/26/2022] [Indexed: 05/19/2023]
Abstract
In eukaryotic cells, biological activities are executed in distinct cellular compartments or organelles. Canonical organelles with membrane-bound structures are well understood. Cells also inherently contain versatile membrane-less organelles (MLOs) that feature liquid or gel-like bodies. A biophysical process termed liquid-liquid phase separation (LLPS) elucidates how MLOs form through dynamic biomolecule assembly. LLPS-related molecules often have multivalency, which is essential for low-affinity inter- or intra-molecule interactions to trigger phase separation. Accumulating evidence shows that LLPS concentrates and organizes desired molecules or segregates unneeded molecules in cells. Thus, MLOs have tunable functional specificity in response to environmental stimuli and metabolic processes. Aberrant LLPS is widely associated with several hallmarks of cancer, including sustained proliferative signaling, growth suppressor evasion, cell death resistance, telomere maintenance, DNA damage repair, etc. Insights into the molecular mechanisms of LLPS provide new insights into cancer therapeutics. Here, the current understanding of the emerging concepts of LLPS and its involvement in cancer are comprehensively reviewed.
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Affiliation(s)
- Jiang Ren
- School of MedicineZhejiang University City CollegeHangzhou215123China
- The Eighth Affiliated HospitalSun Yat‐sen UniversityShenzhen518033China
| | - Zhenyu Zhang
- Department of NeurosurgeryThe First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan450003China
| | - Zhi Zong
- MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling NetworkLife Sciences InstituteZhejiang UniversityHangzhou310058China
| | - Long Zhang
- MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling NetworkLife Sciences InstituteZhejiang UniversityHangzhou310058China
- International Biomed‐X Research Center, Second Affiliated Hospital of Zhejiang University School of MedicineZhejiang UniversityHangzhouChina
- Cancer CenterZhejiang UniversityHangzhou215123China
| | - Fangfang Zhou
- School of MedicineZhejiang University City CollegeHangzhou215123China
- Institutes of Biology and Medical SciencesSoochow UniversitySuzhou215123China
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19
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Geiller HEB, Harvey A, Jones RE, Grimstead JW, Cleal K, Hendrickson EA, Baird DM. ATRX modulates the escape from a telomere crisis. PLoS Genet 2022; 18:e1010485. [PMID: 36350851 PMCID: PMC9678338 DOI: 10.1371/journal.pgen.1010485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 11/21/2022] [Accepted: 10/20/2022] [Indexed: 11/11/2022] Open
Abstract
Telomerase activity is the principal telomere maintenance mechanism in human cancers, however 15% of cancers utilise a recombination-based mechanism referred to as alternative lengthening of telomeres (ALT) that leads to long and heterogenous telomere length distributions. Loss-of-function mutations in the Alpha Thalassemia/Mental Retardation Syndrome X-Linked (ATRX) gene are frequently found in ALT cancers. Here, we demonstrate that the loss of ATRX, coupled with telomere dysfunction during crisis, is sufficient to initiate activation of the ALT pathway and that it confers replicative immortality in human fibroblasts. Additionally, loss of ATRX combined with a telomere-driven crisis in HCT116 epithelial cancer cells led to the initiation of an ALT-like pathway. In these cells, a rapid and precise telomeric elongation and the induction of C-circles was observed; however, this process was transient and the telomeres ultimately continued to erode such that the cells either died or the escape from crisis was associated with telomerase activation. In both of these instances, telomere sequencing revealed that all alleles, irrespective of whether they were elongated, were enriched in variant repeat types, that appeared to be cell-line specific. Thus, our data show that the loss of ATRX combined with telomere dysfunction during crisis induces the ALT pathway in fibroblasts and enables a transient activation of ALT in epithelial cells.
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Affiliation(s)
- Helene E. B. Geiller
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, United Kingdom
| | - Adam Harvey
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Rhiannon E. Jones
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, United Kingdom
| | - Julia W. Grimstead
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, United Kingdom
| | - Kez Cleal
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, United Kingdom
| | - Eric A. Hendrickson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Duncan M. Baird
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, United Kingdom
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20
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Guh CY, Shen HJ, Chen LW, Chiu PC, Liao IH, Lo CC, Chen Y, Hsieh YH, Chang TC, Yen CP, Chen YY, Chen TWW, Chen LY, Wu CS, Egly JM, Chu HPC. XPF activates break-induced telomere synthesis. Nat Commun 2022; 13:5781. [PMID: 36184605 PMCID: PMC9527253 DOI: 10.1038/s41467-022-33428-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 09/16/2022] [Indexed: 11/09/2022] Open
Abstract
Alternative Lengthening of Telomeres (ALT) utilizes a recombination mechanism and break-induced DNA synthesis to maintain telomere length without telomerase, but it is unclear how cells initiate ALT. TERRA, telomeric repeat-containing RNA, forms RNA:DNA hybrids (R-loops) at ALT telomeres. We show that depleting TERRA using an RNA-targeting Cas9 system reduces ALT-associated PML bodies, telomere clustering, and telomere lengthening. TERRA interactome reveals that TERRA interacts with an extensive subset of DNA repair proteins in ALT cells. One of TERRA interacting proteins, the endonuclease XPF, is highly enriched at ALT telomeres and recruited by telomeric R-loops to induce DNA damage response (DDR) independent of CSB and SLX4, and thus triggers break-induced telomere synthesis and lengthening. The attraction of BRCA1 and RAD51 at telomeres requires XPF in FANCM-deficient cells that accumulate telomeric R-loops. Our results suggest that telomeric R-loops activate DDR via XPF to promote homologous recombination and telomere replication to drive ALT.
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Affiliation(s)
- Chia-Yu Guh
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - Hong-Jhih Shen
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - Liv WeiChien Chen
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - Pei-Chen Chiu
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - I-Hsin Liao
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - Chen-Chia Lo
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - Yunfei Chen
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - Yu-Hung Hsieh
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - Ting-Chia Chang
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - Chien-Ping Yen
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - Yi-Yun Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Tom Wei-Wu Chen
- Department of Oncology, National Taiwan University Hospital and Graduate Institute of Oncology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Liuh-Yow Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Ching-Shyi Wu
- Department of Pharmacology, National Taiwan University, Taipei, Taiwan
| | - Jean-Marc Egly
- Department of Functional Genomics and Cancer, IGBMC, CNRS/INSERM/University of Strasbourg, Strasbourg, France.,College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hsueh-Ping Catherine Chu
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan.
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21
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Lacroix E, Audas TE. Keeping up with the condensates: The retention, gain, and loss of nuclear membrane-less organelles. Front Mol Biosci 2022; 9:998363. [PMID: 36203874 PMCID: PMC9530788 DOI: 10.3389/fmolb.2022.998363] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 08/19/2022] [Indexed: 12/04/2022] Open
Abstract
In recent decades, a growing number of biomolecular condensates have been identified in eukaryotic cells. These structures form through phase separation and have been linked to a diverse array of cellular processes. While a checklist of established membrane-bound organelles is present across the eukaryotic domain, less is known about the conservation of membrane-less subcellular structures. Many of these structures can be seen throughout eukaryotes, while others are only thought to be present in metazoans or a limited subset of species. In particular, the nucleus is a hub of biomolecular condensates. Some of these subnuclear domains have been found in a broad range of organisms, which is a characteristic often attributed to essential functionality. However, this does not always appear to be the case. For example, the nucleolus is critical for ribosomal biogenesis and is present throughout the eukaryotic domain, while the Cajal bodies are believed to be similarly conserved, yet these structures are dispensable for organismal survival. Likewise, depletion of the Drosophila melanogaster omega speckles reduces viability, despite the apparent absence of this domain in higher eukaryotes. By reviewing primary research that has analyzed the presence of specific condensates (nucleoli, Cajal bodies, amyloid bodies, nucleolar aggresomes, nuclear speckles, nuclear paraspeckles, nuclear stress bodies, PML bodies, omega speckles, NUN bodies, mei2 dots) in a cross-section of organisms (e.g., human, mouse, D. melanogaster, Caenorhabditis elegans, yeast), we adopt a human-centric view to explore the emergence, retention, and absence of a subset of nuclear biomolecular condensates. This overview is particularly important as numerous biomolecular condensates have been linked to human disease, and their presence in additional species could unlock new and well characterized model systems for health research.
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Affiliation(s)
- Emma Lacroix
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Timothy E. Audas
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, BC, Canada
- *Correspondence: Timothy E. Audas,
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22
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Soranno A, Incicco JJ, De Bona P, Tomko EJ, Galburt EA, Holehouse AS, Galletto R. Shelterin Components Modulate Nucleic Acids Condensation and Phase Separation in the Context of Telomeric DNA. J Mol Biol 2022; 434:167685. [PMID: 35724929 PMCID: PMC9378516 DOI: 10.1016/j.jmb.2022.167685] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/26/2022] [Accepted: 06/10/2022] [Indexed: 01/13/2023]
Abstract
Telomeres are nucleoprotein complexes that protect the ends of chromosomes and are essential for chromosome stability in Eukaryotes. In cells, individual telomeres form distinct globules of finite size that appear to be smaller than expected for bare DNA. Moreover, telomeres can cluster together, form telomere-induced-foci or co-localize with promyelocytic leukemia (PML) nuclear bodies. The physical basis for collapse of individual telomeres and coalescence of multiple ones remains unclear, as does the relationship between these two phenomena. By combining single-molecule force spectroscopy measurements, optical microscopy, turbidity assays, and simulations, we show that the telomere scaffolding protein TRF2 can condense individual DNA chains and drives coalescence of multiple DNA molecules, leading to phase separation and the formation of liquid-like droplets. Addition of the TRF2 binding protein hRap1 modulates phase boundaries and tunes the specificity of solution demixing while simultaneously altering the degree of DNA compaction. Our results suggest that the condensation of single telomeres and formation of biomolecular condensates containing multiple telomeres are two different outcomes driven by the same set of molecular interactions. Moreover, binding partners, such as other telomere components, can alter those interactions to promote single-chain DNA compaction over multiple-chain phase separation.
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Affiliation(s)
- Andrea Soranno
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, United States; Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, United States.
| | - J Jeremías Incicco
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Paolo De Bona
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Eric J Tomko
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Eric A Galburt
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, United States; Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, United States
| | - Roberto Galletto
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, United States.
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23
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Patient-Derived iPSCs Reveal Evidence of Telomere Instability and DNA Repair Deficiency in Coats Plus Syndrome. Genes (Basel) 2022; 13:genes13081395. [PMID: 36011306 PMCID: PMC9407572 DOI: 10.3390/genes13081395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/26/2022] [Accepted: 08/02/2022] [Indexed: 12/11/2022] Open
Abstract
Coats plus (CP) syndrome is an inherited autosomal recessive condition that results from mutations in the conserved telomere maintenance component 1 gene (CTC1). The CTC1 protein functions as a part of the CST protein complex, a protein heterotrimer consisting of CTC1-STN1-TEN1 which promotes telomere DNA synthesis and inhibits telomerase-mediated telomere elongation. However, it is unclear how CTC1 mutations may have an effect on telomere structure and function. For that purpose, we established the very first induced pluripotent stem cell lines (iPSCs) from a compound heterozygous patient with CP carrying deleterious mutations in both alleles of CTC1. Telomere dysfunction and chromosomal instability were assessed in both circulating lymphocytes and iPSCs from the patient and from healthy controls of similar age. The circulating lymphocytes and iPSCs from the CP patient were characterized by their higher telomere length heterogeneity and telomere aberrations compared to those in control cells from healthy donors. Moreover, in contrast to iPSCs from healthy controls, the high levels of telomerase were associated with activation of the alternative lengthening of telomere (ALT) pathway in CP-iPSCs. This was accompanied by inappropriate activation of the DNA repair proteins γH2AX, 53BP1, and ATM, as well as with accumulation of DNA damage, micronuclei, and anaphase bridges. CP-iPSCs presented features of cellular senescence and increased radiation sensitivity. Clonal dicentric chromosomes were identified only in CP-iPSCs after exposure to radiation, thus mirroring the role of telomere dysfunction in their formation. These data demonstrate that iPSCs derived from CP patients can be used as a model system for molecular studies of the CP syndrome and underscores the complexity of telomere dysfunction associated with the defect of DNA repair machinery in the CP syndrome.
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24
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Udagawa O, Kato-Udagawa A, Hirano S. Promyelocytic leukemia nuclear body-like structures can assemble in mouse oocytes. Biol Open 2022; 11:275379. [PMID: 35579421 PMCID: PMC9194678 DOI: 10.1242/bio.059130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 05/06/2022] [Indexed: 11/29/2022] Open
Abstract
Promyelocytic leukemia (PML) nuclear bodies (PML-NBs), a class of membrane-less cellular organelles, participate in various biological activities. PML-NBs are known as the core-shell-type nuclear body, harboring ‘client’ proteins in their core. Although multiple membrane-less organelles work in the oocyte nucleus, PML-NBs have been predicted to be absent from oocytes. Here, we show that some well-known PML clients (but not endogenous PML) co-localized with small ubiquitin-related modifier (SUMO) protein in the nucleolus and peri-centromeric heterochromatin of maturing oocytes. In oocytes devoid of PML-NBs, endogenous PML protein localized in the vicinity of chromatin. During and after meiotic resumption, PML co-localized with SUMO gathering around chromosomes. To examine the benefit of the PML-NB-free intranuclear milieu in oocytes, we deliberately assembled PML-NBs by microinjecting human PML-encoding plasmids into oocytes. Under conditions of limited SUMO availability, assembled PML-NBs tended to cluster. Upon proteotoxic stress, SUMO delocalized from peri-centromeric heterochromatin and co-localized with SC35 (a marker of nuclear speckles)-positive large compartments, which was disturbed by pre-assembled PML-NBs. These observations suggest that the PML-NB-free intranuclear environment helps reserve SUMO for emergent responses by redirecting the flux of SUMO otherwise needed to maintain PML-NB dynamics. Summary: PML-NB-free intranuclear environment in the oocyte helps reserve SUMO for emergent responses by redirecting the flux of SUMO otherwise needed to maintain PML-NB dynamics.
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Affiliation(s)
- Osamu Udagawa
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Japan
| | - Ayaka Kato-Udagawa
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Japan
| | - Seishiro Hirano
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Japan
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25
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Bhargava R, Lynskey ML, O’Sullivan RJ. New twists to the ALTernative endings at telomeres. DNA Repair (Amst) 2022; 115:103342. [DOI: 10.1016/j.dnarep.2022.103342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/02/2022] [Accepted: 05/05/2022] [Indexed: 11/30/2022]
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26
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PITX1 Is a Regulator of TERT Expression in Prostate Cancer with Prognostic Power. Cancers (Basel) 2022; 14:cancers14051267. [PMID: 35267575 PMCID: PMC8909694 DOI: 10.3390/cancers14051267] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 02/05/2023] Open
Abstract
Simple Summary Most prostate cancer is of an indolent form and is curable. However, some prostate cancer belongs to rather aggressive subtypes leading to metastasis and death, and immediate therapy is mandatory. However, for these, the therapeutic options are highly invasive, such as radical prostatectomy, radiation or brachytherapy. Hence, a precise diagnosis of these tumor subtypes is needed, and the thus far applied diagnostic means are insufficient for this. Besides this, for their endless cell divisions, prostate cancer cells need the enzyme telomerase to elongate their telomeres (chromatin endings). In this study, we developed a gene regulatory model based on large data from transcription profiles from prostate cancer and chromatin-immuno-precipitation studies. We identified the developmental regulator PITX1 regulating telomerase. Besides observing experimental evidence of PITX1′s functional role in telomerase regulation, we also found PITX1 serving as a prognostic marker, as concluded from an analysis of more than 15,000 prostate cancer samples. Abstract The current risk stratification in prostate cancer (PCa) is frequently insufficient to adequately predict disease development and outcome. One hallmark of cancer is telomere maintenance. For telomere maintenance, PCa cells exclusively employ telomerase, making it essential for this cancer entity. However, TERT, the catalytic protein component of the reverse transcriptase telomerase, itself does not suit as a prognostic marker for prostate cancer as it is rather low expressed. We investigated if, instead of TERT, transcription factors regulating TERT may suit as prognostic markers. To identify transcription factors regulating TERT, we developed and applied a new gene regulatory modeling strategy to a comprehensive transcriptome dataset of 445 primary PCa. Six transcription factors were predicted as TERT regulators, and most prominently, the developmental morphogenic factor PITX1. PITX1 expression positively correlated with telomere staining intensity in PCa tumor samples. Functional assays and chromatin immune-precipitation showed that PITX1 activates TERT expression in PCa cells. Clinically, we observed that PITX1 is an excellent prognostic marker, as concluded from an analysis of more than 15,000 PCa samples. PITX1 expression in tumor samples associated with (i) increased Ki67 expression indicating increased tumor growth, (ii) a worse prognosis, and (iii) correlated with telomere length.
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27
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Dan J, Zhou Z, Wang F, Wang H, Guo R, Keefe DL, Liu L. Zscan4 Contributes to Telomere Maintenance in Telomerase-Deficient Late Generation Mouse ESCs and Human ALT Cancer Cells. Cells 2022; 11:cells11030456. [PMID: 35159266 PMCID: PMC8834411 DOI: 10.3390/cells11030456] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 02/06/2023] Open
Abstract
Proper telomere length is essential for indefinite self-renewal of embryonic stem (ES) cells and cancer cells. Telomerase-deficient late generation mouse ES cells and human ALT cancer cells are able to propagate for numerous passages, suggesting telomerase-independent mechanisms responding for telomere maintenance. However, the underlying mechanisms ensuring the telomere length maintenance are unclear. Here, using late generation telomerase KO (G4 Terc-/-) ESCs as a model, we show that Zscan4, highly upregulated in G4 Terc-/- ESCs, is responsible for the prolonged culture of these cells with stably short telomeres. Mechanistically, G4 Terc-/- ESCs showed reduced levels of DNA methylation and H3K9me3 at Zscan4 promoter and subtelomeres, which relieved the expression of Zscan4. Similarly, human ZSCAN4 was also derepressed by reduced H3K9me3 at its promoter in ALT U2 OS cells, and depletion of ZSCAN4 significantly shortened telomeres. Our results define a similar conserved pathway contributing to the telomere maintenance in telomerase-deficient late generation mESCs and human ALT U2OS cancer cells.
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Affiliation(s)
- Jiameng Dan
- State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin 300071, China; (Z.Z.); (H.W.); (R.G.)
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, Yunnan 650500, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan 650500, China
- Correspondence: (J.D.); (L.L.)
| | - Zhongcheng Zhou
- State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin 300071, China; (Z.Z.); (H.W.); (R.G.)
| | - Fang Wang
- Department of Obstetrics and Gynecology, New York University Langone Medical Center, New York, NY 10016, USA; (F.W.); (D.L.K.)
| | - Hua Wang
- State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin 300071, China; (Z.Z.); (H.W.); (R.G.)
| | - Renpeng Guo
- State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin 300071, China; (Z.Z.); (H.W.); (R.G.)
| | - David L. Keefe
- Department of Obstetrics and Gynecology, New York University Langone Medical Center, New York, NY 10016, USA; (F.W.); (D.L.K.)
| | - Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin 300071, China; (Z.Z.); (H.W.); (R.G.)
- Correspondence: (J.D.); (L.L.)
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28
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Jack A, Kim Y, Strom AR, Lee DSW, Williams B, Schaub JM, Kellogg EH, Finkelstein IJ, Ferro LS, Yildiz A, Brangwynne CP. Compartmentalization of telomeres through DNA-scaffolded phase separation. Dev Cell 2022; 57:277-290.e9. [PMID: 35077681 PMCID: PMC8988007 DOI: 10.1016/j.devcel.2021.12.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 08/25/2021] [Accepted: 12/15/2021] [Indexed: 12/20/2022]
Abstract
Telomeres form unique nuclear compartments that prevent degradation and fusion of chromosome ends by recruiting shelterin proteins and regulating access of DNA damage repair factors. To understand how these dynamic components protect chromosome ends, we combine in vivo biophysical interrogation and in vitro reconstitution of human shelterin. We show that shelterin components form multicomponent liquid condensates with selective biomolecular partitioning on telomeric DNA. Tethering and anomalous diffusion prevent multiple telomeres from coalescing into a single condensate in mammalian cells. However, telomeres coalesce when brought into contact via an optogenetic approach. TRF1 and TRF2 subunits of shelterin drive phase separation, and their N-terminal domains specify interactions with telomeric DNA in vitro. Telomeric condensates selectively recruit telomere-associated factors and regulate access of DNA damage repair factors. We propose that shelterin mediates phase separation of telomeric chromatin, which underlies the dynamic yet persistent nature of the end-protection mechanism.
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Affiliation(s)
- Amanda Jack
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA
| | - Yoonji Kim
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Amy R Strom
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Daniel S W Lee
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Byron Williams
- Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
| | - Jeffrey M Schaub
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | | | - Ilya J Finkelstein
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Luke S Ferro
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
| | - Ahmet Yildiz
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA; Physics Department, University of California, Berkeley, CA 94720, USA.
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton University, Princeton NJ 08544, USA.
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29
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Barroso-González J, García-Expósito L, Galaviz P, Lynskey ML, Allen JAM, Hoang S, Watkins SC, Pickett HA, O'Sullivan RJ. Anti-recombination function of MutSα restricts telomere extension by ALT-associated homology-directed repair. Cell Rep 2021; 37:110088. [PMID: 34879271 PMCID: PMC8724847 DOI: 10.1016/j.celrep.2021.110088] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/13/2021] [Accepted: 11/10/2021] [Indexed: 01/02/2023] Open
Abstract
Alternative lengthening of telomeres (ALT) is a telomere-elongation mechanism observed in ~15% of cancer subtypes. Current models indicate that ALT is mediated by homology-directed repair mechanisms. By disrupting MSH6 gene expression, we show that the deficiency of MutSα (MSH2/MSH6) DNA mismatch repair complex causes striking telomere hyperextension. Mechanistically, we show MutSα is specifically recruited to telomeres in ALT cells by associating with the proliferating-cell nuclear antigen (PCNA) subunit of the ALT telomere replisome. We also provide evidence that MutSα counteracts Bloom (BLM) helicase, which adopts a crucial role in stabilizing hyper-extended telomeres and maintaining the survival of MutSα-deficient ALT cancer cells. Lastly, we propose a model in which MutSα deficiency impairs heteroduplex rejection, leading to premature initiation of telomere DNA synthesis that coincides with an accumulation of telomere variant repeats (TVRs). These findings provide evidence that the MutSα DNA mismatch repair complex acts to restrain unwarranted ALT. Barroso-Gonzalez et al. show that the mismatch repair complex MutSα restricts the alternative lengthening of telomeres (ALT) pathway in cancer cells. MutSα has an anti-recombination function and limits recombination between heteroduplex sequences at telomeres, in part by counteracting the Bloom helicase (BLM).
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Affiliation(s)
- Jonathan Barroso-González
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Laura García-Expósito
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Pablo Galaviz
- Bioinformatics Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Michelle Lee Lynskey
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Joshua A M Allen
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - SongMy Hoang
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Simon C Watkins
- Department of Cell Biology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Hilda A Pickett
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Roderick J O'Sullivan
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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30
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Peng Q, Zhou M, Zuo S, Liu Y, Li X, Yang Y, He Q, Yu X, Zhou J, He Z, He Q. Nuclear Factor Related to KappaB Binding Protein ( NFRKB) Is a Telomere-Associated Protein and Involved in Liver Cancer Development. DNA Cell Biol 2021; 40:1298-1307. [PMID: 34591601 DOI: 10.1089/dna.2021.0486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Alternative lengthening of telomeres (ALT) is a homologous recombination-based telomere maintenance mechanism activated in 10-15% of human cancers. Although significant progress has been made, the key regulators of the ALT pathway and its role in cancer development remain elusive. Bioinformatics methods were used to predict novel telomere-associated proteins (TAPs) by analysis of large-scale ChIP-Seq data. Immunostaining and fluorescence in situ hybridization experiments were applied to detect the subcellular location of target genes and telomeres. Western blot and reverse transcription-polymerase chain reaction (RT-PCR) were used to examine the expression of targeting genes. Overall survival (OS) analyses were used to evaluate the relationship between gene expression and survival time; immunohistochemistry was used to detect the distribution of target genes in liver cancer tissues. We found that nuclear factor related to kappaB binding protein (NFRKB), a metazoan-specific subunit of the INO80 complex, can associate with telomeres in human ALT cells. Loss of NFRKB induces dysfunction of telomeres and less PML bodies in U2OS cells. In addition, NFRKB is low/moderately expressed in cytoplasm of normal hepatocytes but heavily accumulating in the nucleus of liver cancer cells. Finally, the high expression of NFRKB is associated with short OS time and poor prognosis. NFRKB is a TAP and protects telomeres from DNA damage in ALT cells. It is highly expressed in hepatocellular carcinoma (HCC) cells and predicts a poor prognosis. NFRKB may be a promising prognostic biomarker for the treatment of HCC in the future.
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Affiliation(s)
- Qiyao Peng
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, Hunan Normal University School of Medicine, Changsha, China
| | - Mingqing Zhou
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, Hunan Normal University School of Medicine, Changsha, China
| | - Shanru Zuo
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, Hunan Normal University School of Medicine, Changsha, China
| | - Yucong Liu
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, Hunan Normal University School of Medicine, Changsha, China
| | - Xueguang Li
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, Hunan Normal University School of Medicine, Changsha, China
| | - Yide Yang
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, Hunan Normal University School of Medicine, Changsha, China
| | - Quanze He
- The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, China
| | - Xing Yu
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, Hunan Normal University School of Medicine, Changsha, China
| | - Junhua Zhou
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, Hunan Normal University School of Medicine, Changsha, China
| | - Zuping He
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, Hunan Normal University School of Medicine, Changsha, China
| | - Quanyuan He
- The Key Laboratory of Model Animals and Stem Cell Biology in Hunan Province, Hunan Normal University School of Medicine, Changsha, China
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31
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Wang C, Songyang Z, Huang Y. TRIM28 inhibits alternative lengthening of telomere phenotypes by protecting SETDB1 from degradation. Cell Biosci 2021; 11:149. [PMID: 34330324 PMCID: PMC8325274 DOI: 10.1186/s13578-021-00660-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 07/15/2021] [Indexed: 01/04/2023] Open
Abstract
Background About 10–15% of tumor cells extend telomeres through the alternative lengthening of telomeres (ALT) mechanism, which is a recombination-dependent replication pathway. It is generally believed that ALT cells are related to the chromatin modification of telomeres. However, the mechanism of ALT needs to be further explored. Results Here we found that TRIM28/KAP1 is preferentially located on the telomeres of ALT cells and interacts with telomeric shelterin/telosome complex. Knocking down TRIM28 in ALT cells delayed cell growth, decreased the level of C-circle which is one kind of extrachromosomal circular telomeric DNA, increased the frequency of ALT-associated promyelocytic leukemia bodies (APBs), led to telomere prolongation and increased the telomere sister chromatid exchange in ALT cells. Mechanistically, TRIM28 protects telomere histone methyltransferase SETDB1 from degradation, thus maintaining the H3K9me3 heterochromatin state of telomere DNA. Conclusions Our work provides a model that TRIM28 inhibits alternative lengthening of telomere phenotypes by protecting SETDB1 from degradation. In general, our results reveal the mechanism of telomere heterochromatin maintenance and its effect on ALT, and TRIM28 may serve as a target for the treatment of ALT tumor cells. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-021-00660-y.
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Affiliation(s)
- 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
| | - 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, 77030, USA.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 510005, China
| | - Yan 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.
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32
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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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MacKenzie D, Watters AK, To JT, Young MW, Muratori J, Wilkoff MH, Abraham RG, Plummer MM, Zhang D. ALT Positivity in Human Cancers: Prevalence and Clinical Insights. Cancers (Basel) 2021; 13:2384. [PMID: 34069193 PMCID: PMC8156225 DOI: 10.3390/cancers13102384] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/07/2021] [Accepted: 05/11/2021] [Indexed: 02/08/2023] Open
Abstract
Many exciting advances in cancer-related telomere biology have been made in the past decade. Of these recent advances, great progress has also been made with respect to the Alternative Lengthening of Telomeres (ALT) pathway. Along with a better understanding of the molecular mechanism of this unique telomere maintenance pathway, many studies have also evaluated ALT activity in various cancer subtypes. We first briefly review and assess a variety of commonly used ALT biomarkers. Then, we provide both an update on ALT-positive (ALT+) tumor prevalence as well as a systematic clinical assessment of the presently studied ALT+ malignancies. Additionally, we discuss the pathogenetic alterations in ALT+ cancers, for example, the mutation status of ATRX and DAXX, and their correlations with the activation of the ALT pathway. Finally, we highlight important ALT+ clinical associations within each cancer subtype and subdivisions within, as well as their prognoses. We hope this alternative perspective will allow scientists, clinicians, and drug developers to have greater insight into the ALT cancers so that together, we may develop more efficacious treatments and improved management strategies to meet the urgent needs of cancer patients.
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Affiliation(s)
| | | | | | | | | | | | | | - Maria M. Plummer
- Department of Biomedical Sciences, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY 11568, USA; (D.M.J.); (A.K.W.); (J.T.T.); (M.W.Y.); (J.M.); (M.H.W.); (R.G.A.)
| | - Dong Zhang
- Department of Biomedical Sciences, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY 11568, USA; (D.M.J.); (A.K.W.); (J.T.T.); (M.W.Y.); (J.M.); (M.H.W.); (R.G.A.)
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34
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Mutations inhibiting KDM4B drive ALT activation in ATRX-mutated glioblastomas. Nat Commun 2021; 12:2584. [PMID: 33972520 PMCID: PMC8110556 DOI: 10.1038/s41467-021-22543-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 03/16/2021] [Indexed: 12/24/2022] Open
Abstract
Alternative Lengthening of Telomeres (ALT) is a telomere maintenance pathway utilised in 15% of cancers. ALT cancers are strongly associated with inactivating mutations in ATRX; yet loss of ATRX alone is insufficient to trigger ALT, suggesting that additional cooperating factors are involved. We identify H3.3G34R and IDH1/2 mutations as two such factors in ATRX-mutated glioblastomas. Both mutations are capable of inactivating histone demethylases, and we identify KDM4B as the key demethylase inactivated in ALT. Mouse embryonic stem cells inactivated for ATRX, TP53, TERT and KDM4B (KDM4B knockout or H3.3G34R) show characteristic features of ALT. Conversely, KDM4B over-expression in ALT cancer cells abrogates ALT-associated features. In this work, we demonstrate that inactivation of KDM4B, through H3.3G34R or IDH1/2 mutations, acts in tandem with ATRX mutations to promote ALT in glioblastomas. Alternative Lengthening of Telomeres (ALT) is a telomere maintenance pathway utilised in 15% of cancers that have been associated with mutations in ATRX. Here the authors reveal a functional role of histone demethylases KDM4B in regulating ALT activation.
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35
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Segura-Bayona S, Villamor-Payà M, Attolini CSO, Koenig LM, Sanchiz-Calvo M, Boulton SJ, Stracker TH. Tousled-Like Kinases Suppress Innate Immune Signaling Triggered by Alternative Lengthening of Telomeres. Cell Rep 2021; 32:107983. [PMID: 32755577 PMCID: PMC7408502 DOI: 10.1016/j.celrep.2020.107983] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/30/2020] [Accepted: 07/09/2020] [Indexed: 12/11/2022] Open
Abstract
The Tousled-like kinases 1 and 2 (TLK1/2) control histone deposition through the ASF1 histone chaperone and influence cell cycle progression and genome maintenance, yet the mechanisms underlying TLK-mediated genome stability remain uncertain. Here, we show that TLK loss results in severe chromatin decompaction and altered genome accessibility, particularly affecting heterochromatic regions. Failure to maintain heterochromatin increases spurious transcription of repetitive elements and induces features of alternative lengthening of telomeres (ALT). TLK depletion culminates in a cGAS-STING-TBK1-mediated innate immune response that is independent of replication-stress signaling and attenuated by the depletion of factors required to produce extra-telomeric DNA. Analysis of human cancers reveals that chromosomal instability correlates with high TLK2 and low STING levels in many cohorts. Based on these findings, we propose that high TLK levels contribute to immune evasion in chromosomally unstable and ALT+ cancers. TLK-deficient cells have increased accessibility at heterochromatin regions TLK1/2 suppress spurious transcription and telomere hyper-recombination Extra-telomeric DNA generated upon TLK loss promotes innate immune signaling cGAS-STING-TBK1 signaling in TLK-deficient cells is independent of replication stress
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Affiliation(s)
- Sandra Segura-Bayona
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain; The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
| | - Marina Villamor-Payà
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain
| | - Camille Stephan-Otto Attolini
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain
| | - Lars M Koenig
- Division of Clinical Pharmacology, University Hospital, LMU Munich, 80337 Munich, Germany
| | - Maria Sanchiz-Calvo
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain
| | - Simon J Boulton
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Travis H Stracker
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain.
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36
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Zhao R, Chenoweth DM, Zhang H. Chemical Dimerization-Induced Protein Condensates on Telomeres. J Vis Exp 2021. [PMID: 33900288 DOI: 10.3791/62173] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Chromatin-associated condensates are implicated in many nuclear processes, but the underlying mechanisms remain elusive. This protocol describes a chemically-induced protein dimerization system to create condensates on telomeres. The chemical dimerizer consists of two linked ligands that can each bind to a protein: Halo ligand to Halo-enzyme and trimethoprim (TMP) to E. coli dihydrofolate reductase (eDHFR), respectively. Fusion of Halo enzyme to a telomere protein anchors dimerizers to telomeres through covalent Halo ligand-enzyme binding. Binding of TMP to eDHFR recruits eDHFR-fused phase separating proteins to telomeres and induces condensate formation. Because TMP-eDHFR interaction is non-covalent, condensation can be reversed by using excess free TMP to compete with the dimerizer for eDHFR binding. An example of inducing promyelocytic leukemia (PML) nuclear body formation on telomeres and determining condensate growth, dissolution, localization and composition is shown. This method can be easily adapted to induce condensates at other genomic locations by fusing Halo to a protein that directly binds to the local chromatin or to dCas9 that is targeted to the genomic locus with a guide RNA. By offering the temporal resolution required for single cell live imaging while maintaining phase separation in a population of cells for biochemical assays, this method is suitable for probing both the formation and function of chromatin-associated condensates.
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Affiliation(s)
- Rongwei Zhao
- Department of Biological Sciences, Mellon College of Science, Carnegie Mellon University
| | - David M Chenoweth
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania
| | - Huaiying Zhang
- Department of Biological Sciences, Mellon College of Science, Carnegie Mellon University;
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37
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Yang CW, Hsieh MH, Sun HJ, Teng SC. Nuclear envelope tethering inhibits the formation of ALT-associated PML bodies in ALT cells. Aging (Albany NY) 2021; 13:10490-10516. [PMID: 33820871 PMCID: PMC8064153 DOI: 10.18632/aging.202810] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 02/16/2021] [Indexed: 12/12/2022]
Abstract
Telomere length homeostasis is essential for maintaining genomic stability and cancer proliferation. Telomerase-negative cancer cells undergo recombination-mediated alternative lengthening of telomeres. Telomeres associate with the nuclear envelope through the shelterin RAP1 and nuclear envelope SUN1 proteins. However, how the associations between telomeres and the nuclear envelope affect the progression of telomere recombination is not understood. Here, we show that telomere anchorage might inhibit telomere-telomere recombination. SUN1 depletion stimulates the formation of alternative lengthening of telomeres-associated promyelocytic leukemia bodies in ALT cells. In contrast, overexpression of a telomere-nuclear envelope-tethering chimera protein, RAP1-SUN1, suppresses APB formation. Moreover, inhibition of this nuclear envelope attachment alleviates the requirement of TOP3α for resolving the supercoiling pressure during telomere recombination. A coimmunoprecipitation assay revealed that the SUN1 N-terminal nucleoplasmic domain interacts with the RAP1 middle coil domain, and phosphorylation-mimetic mutations in RAP1 inhibit this interaction. However, abolishing the RAP1-SUN1 interaction does not hinder APB formation, which hints at the existence of another SUN1-dependent telomere anchorage pathway. In summary, our results reveal an inhibitory role of telomere-nuclear envelope association in telomere-telomere recombination and imply the presence of redundant pathways for the telomere-nuclear envelope association in ALT cells.
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Affiliation(s)
- Chia-Wei Yang
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
| | - Meng-Hsun Hsieh
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
| | - Hao-Jhe Sun
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
| | - Shu-Chun Teng
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan.,Center of Precision Medicine, National Taiwan University, Taipei 10051, Taiwan
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38
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Kaur E, Agrawal R, Sengupta S. Functions of BLM Helicase in Cells: Is It Acting Like a Double-Edged Sword? Front Genet 2021; 12:634789. [PMID: 33777104 PMCID: PMC7994599 DOI: 10.3389/fgene.2021.634789] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 02/11/2021] [Indexed: 12/14/2022] Open
Abstract
DNA damage repair response is an important biological process involved in maintaining the fidelity of the genome in eukaryotes and prokaryotes. Several proteins that play a key role in this process have been identified. Alterations in these key proteins have been linked to different diseases including cancer. BLM is a 3′−5′ ATP-dependent RecQ DNA helicase that is one of the most essential genome stabilizers involved in the regulation of DNA replication, recombination, and both homologous and non-homologous pathways of double-strand break repair. BLM structure and functions are known to be conserved across many species like yeast, Drosophila, mouse, and human. Genetic mutations in the BLM gene cause a rare, autosomal recessive disorder, Bloom syndrome (BS). BS is a monogenic disease characterized by genomic instability, premature aging, predisposition to cancer, immunodeficiency, and pulmonary diseases. Hence, these characteristics point toward BLM being a tumor suppressor. However, in addition to mutations, BLM gene undergoes various types of alterations including increase in the copy number, transcript, and protein levels in multiple types of cancers. These results, along with the fact that the lack of wild-type BLM in these cancers has been associated with increased sensitivity to chemotherapeutic drugs, indicate that BLM also has a pro-oncogenic function. While a plethora of studies have reported the effect of BLM gene mutations in various model organisms, there is a dearth in the studies undertaken to investigate the effect of its oncogenic alterations. We propose to rationalize and integrate the dual functions of BLM both as a tumor suppressor and maybe as a proto-oncogene, and enlist the plausible mechanisms of its deregulation in cancers.
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Affiliation(s)
- Ekjot Kaur
- Signal Transduction Laboratory-2, National Institute of Immunology, New Delhi, India
| | - Ritu Agrawal
- Signal Transduction Laboratory-2, National Institute of Immunology, New Delhi, India
| | - Sagar Sengupta
- Signal Transduction Laboratory-2, National Institute of Immunology, New Delhi, India
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39
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Zhang JM, Genois MM, Ouyang J, Lan L, Zou L. Alternative lengthening of telomeres is a self-perpetuating process in ALT-associated PML bodies. Mol Cell 2021; 81:1027-1042.e4. [PMID: 33453166 PMCID: PMC8245000 DOI: 10.1016/j.molcel.2020.12.030] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 11/03/2020] [Accepted: 12/15/2020] [Indexed: 01/16/2023]
Abstract
Alternative lengthening of telomeres (ALT) is mediated by break-induced replication (BIR), but how BIR is regulated at telomeres is poorly understood. Here, we show that telomeric BIR is a self-perpetuating process. By tethering PML-IV to telomeres, we induced telomere clustering in ALT-associated PML bodies (APBs) and a POLD3-dependent ATR response at telomeres, showing that BIR generates replication stress. Ablation of BLM helicase activity in APBs abolishes telomere synthesis but causes multiple chromosome bridges between telomeres, revealing a function of BLM in processing inter-telomere BIR intermediates. Interestingly, the accumulation of BLM in APBs requires its own helicase activity and POLD3, suggesting that BIR triggers a feedforward loop to further recruit BLM. Enhancing BIR induces PIAS4-mediated TRF2 SUMOylation, and PIAS4 loss deprives APBs of repair proteins and compromises ALT telomere synthesis. Thus, a BLM-driven and PIAS4-mediated feedforward loop operates in APBs to perpetuate BIR, providing a critical mechanism to extend ALT telomeres.
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Affiliation(s)
- Jia-Min Zhang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Marie-Michelle Genois
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Jian Ouyang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Li Lan
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
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40
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Corpet A, Kleijwegt C, Roubille S, Juillard F, Jacquet K, Texier P, Lomonte P. PML nuclear bodies and chromatin dynamics: catch me if you can! Nucleic Acids Res 2020; 48:11890-11912. [PMID: 33068409 PMCID: PMC7708061 DOI: 10.1093/nar/gkaa828] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/15/2020] [Accepted: 09/18/2020] [Indexed: 12/17/2022] Open
Abstract
Eukaryotic cells compartmentalize their internal milieu in order to achieve specific reactions in time and space. This organization in distinct compartments is essential to allow subcellular processing of regulatory signals and generate specific cellular responses. In the nucleus, genetic information is packaged in the form of chromatin, an organized and repeated nucleoprotein structure that is a source of epigenetic information. In addition, cells organize the distribution of macromolecules via various membrane-less nuclear organelles, which have gathered considerable attention in the last few years. The macromolecular multiprotein complexes known as Promyelocytic Leukemia Nuclear Bodies (PML NBs) are an archetype for nuclear membrane-less organelles. Chromatin interactions with nuclear bodies are important to regulate genome function. In this review, we will focus on the dynamic interplay between PML NBs and chromatin. We report how the structure and formation of PML NBs, which may involve phase separation mechanisms, might impact their functions in the regulation of chromatin dynamics. In particular, we will discuss how PML NBs participate in the chromatinization of viral genomes, as well as in the control of specific cellular chromatin assembly pathways which govern physiological mechanisms such as senescence or telomere maintenance.
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Affiliation(s)
- Armelle Corpet
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, LabEx DEVweCAN, Institut NeuroMyoGène (INMG), team Chromatin Dynamics, Nuclear Domains, Virus F-69008, Lyon, France
| | - Constance Kleijwegt
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, LabEx DEVweCAN, Institut NeuroMyoGène (INMG), team Chromatin Dynamics, Nuclear Domains, Virus F-69008, Lyon, France
| | - Simon Roubille
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, LabEx DEVweCAN, Institut NeuroMyoGène (INMG), team Chromatin Dynamics, Nuclear Domains, Virus F-69008, Lyon, France
| | - Franceline Juillard
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, LabEx DEVweCAN, Institut NeuroMyoGène (INMG), team Chromatin Dynamics, Nuclear Domains, Virus F-69008, Lyon, France
| | - Karine Jacquet
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, LabEx DEVweCAN, Institut NeuroMyoGène (INMG), team Chromatin Dynamics, Nuclear Domains, Virus F-69008, Lyon, France
| | - Pascale Texier
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, LabEx DEVweCAN, Institut NeuroMyoGène (INMG), team Chromatin Dynamics, Nuclear Domains, Virus F-69008, Lyon, France
| | - Patrick Lomonte
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, LabEx DEVweCAN, Institut NeuroMyoGène (INMG), team Chromatin Dynamics, Nuclear Domains, Virus F-69008, Lyon, France
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41
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Jiang S, Fagman JB, Chen C, Alberti S, Liu B. Protein phase separation and its role in tumorigenesis. eLife 2020; 9:60264. [PMID: 33138914 PMCID: PMC7609067 DOI: 10.7554/elife.60264] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 10/21/2020] [Indexed: 12/13/2022] Open
Abstract
Cancer is a disease characterized by uncontrolled cell proliferation, but the precise pathological mechanisms underlying tumorigenesis often remain to be elucidated. In recent years, condensates formed by phase separation have emerged as a new principle governing the organization and functional regulation of cells. Increasing evidence links cancer-related mutations to aberrantly altered condensate assembly, suggesting that condensates play a key role in tumorigenesis. In this review, we summarize and discuss the latest progress on the formation, regulation, and function of condensates. Special emphasis is given to emerging evidence regarding the link between condensates and the initiation and progression of cancers.
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Affiliation(s)
- Shan Jiang
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Johan Bourghardt Fagman
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Changyan Chen
- Department of Oncology at the Department of Clinical Sciences, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Simon Alberti
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Beidong Liu
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.,Center for Large-scale cell-based screening, Faculty of Science, University of Gothenburg, Gothenburg, Sweden
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42
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Wassing IE, Esashi F. RAD51: Beyond the break. Semin Cell Dev Biol 2020; 113:38-46. [PMID: 32938550 PMCID: PMC8082279 DOI: 10.1016/j.semcdb.2020.08.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/14/2020] [Accepted: 08/28/2020] [Indexed: 01/30/2023]
Abstract
As the primary catalyst of homologous recombination (HR) in vertebrates, RAD51 has been extensively studied in the context of repair of double-stranded DNA breaks (DSBs). With recent advances in the understanding of RAD51 function extending beyond DSBs, the importance of RAD51 throughout DNA metabolism has become increasingly clear. Here we review the suggested roles of RAD51 beyond HR, specifically focusing on their interplay with DNA replication and the maintenance of genomic stability, in which RAD51 function emerges as a double-edged sword.
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Affiliation(s)
- Isabel E Wassing
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Fumiko Esashi
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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43
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Valles GJ, Bezsonova I, Woodgate R, Ashton NW. USP7 Is a Master Regulator of Genome Stability. Front Cell Dev Biol 2020; 8:717. [PMID: 32850836 PMCID: PMC7419626 DOI: 10.3389/fcell.2020.00717] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/13/2020] [Indexed: 12/25/2022] Open
Abstract
Genetic alterations, including DNA mutations and chromosomal abnormalities, are primary drivers of tumor formation and cancer progression. These alterations can endow cells with a selective growth advantage, enabling cancers to evade cell death, proliferation limits, and immune checkpoints, to metastasize throughout the body. Genetic alterations occur due to failures of the genome stability pathways. In many cancers, the rate of alteration is further accelerated by the deregulation of these processes. The deubiquitinating enzyme ubiquitin specific protease 7 (USP7) has recently emerged as a key regulator of ubiquitination in the genome stability pathways. USP7 is also deregulated in many cancer types, where deviances in USP7 protein levels are correlated with cancer progression. In this work, we review the increasingly evident role of USP7 in maintaining genome stability, the links between USP7 deregulation and cancer progression, as well as the rationale of targeting USP7 in cancer therapy.
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Affiliation(s)
- Gabrielle J Valles
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, United States
| | - Irina Bezsonova
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, United States
| | - Roger Woodgate
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Nicholas W Ashton
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
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Aramburu T, Plucinsky S, Skordalakes E. POT1-TPP1 telomere length regulation and disease. Comput Struct Biotechnol J 2020; 18:1939-1946. [PMID: 32774788 PMCID: PMC7385035 DOI: 10.1016/j.csbj.2020.06.040] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/24/2020] [Accepted: 06/27/2020] [Indexed: 12/27/2022] Open
Abstract
Telomeres are DNA repeats at the ends of linear chromosomes and are replicated by telomerase, a ribonucleoprotein reverse transcriptase. Telomere length regulation and chromosome end capping are essential for genome stability and are mediated primarily by the shelterin and CST complexes. POT1-TPP1, a subunit of shelterin, binds the telomeric overhang, suppresses ATR-dependent DNA damage response, and recruits telomerase to telomeres for DNA replication. POT1 localization to telomeres and chromosome end protection requires its interaction with TPP1. Therefore, the POT1-TPP1 complex is critical to telomere maintenance and full telomerase processivity. The aim of this mini-review is to summarize recent POT1-TPP1 structural studies and discuss how the complex contributes to telomere length regulation. In addition, we review how disruption of POT1-TPP1 function leads to human disease.
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Key Words
- ATM, Ataxia Telangiectasia Mutated protein
- ATR, Ataxia Telangiectasia and Rad3-related Protein
- CST, CTC1, Stn1 and Ten1
- CTC1, Conserved Telomere Capping Protein 1
- POT1
- POT1, Protection of telomere 1
- RAP1, Repressor/Activator Protein 1
- RPA, Replication Protein A
- SMCHD1, Structural Maintenance Of Chromosomes Flexible Hinge Domain Containing 1
- Shelterin
- Stn1, Suppressor of Cdc Thirteen
- TERC, Telomerase RNA
- TERT, Telomerase Reverse Transcriptase
- TIN2, TRF1- and TRF2-Interacting Nuclear Protein 2
- TPP1
- TPP1 also known as ACD, Adrenocortical Dysplasia Protein Homolog
- TRF1, Telomere Repeat binding Factor 1
- TRF2, Telomere Repeat binding Factor 2
- TSPYL5, Testis-specific Y-encoded-like protein 5
- Telomerase
- Telomeres
- Ten1, Telomere Length Regulation Protein
- USP7, ubiquitin-specific-processing protease 7
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Frank L, Rippe K. Repetitive RNAs as Regulators of Chromatin-Associated Subcompartment Formation by Phase Separation. J Mol Biol 2020; 432:4270-4286. [DOI: 10.1016/j.jmb.2020.04.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 04/14/2020] [Accepted: 04/14/2020] [Indexed: 12/21/2022]
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Zhang H, Zhao R, Tones J, Liu M, Dilley RL, Chenoweth DM, Greenberg RA, Lampson MA. Nuclear body phase separation drives telomere clustering in ALT cancer cells. Mol Biol Cell 2020; 31:2048-2056. [PMID: 32579423 PMCID: PMC7543070 DOI: 10.1091/mbc.e19-10-0589] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Telomerase-free cancer cells employ a recombination-based alternative lengthening of telomeres (ALT) pathway that depends on ALT-associated promyelocytic leukemia nuclear bodies (APBs), whose function is unclear. We find that APBs behave as liquid condensates in response to telomere DNA damage, suggesting two potential functions: condensation to enrich DNA repair factors and coalescence to cluster telomeres. To test these models, we developed a chemically induced dimerization approach to induce de novo APB condensation in live cells without DNA damage. We show that telomere-binding protein sumoylation nucleates APB condensation via interactions between small ubiquitin-like modifier (SUMO) and SUMO interaction motif (SIM), and that APB coalescence drives telomere clustering. The induced APBs lack DNA repair factors, indicating that APB functions in promoting telomere clustering can be uncoupled from enriching DNA repair factors. Indeed, telomere clustering relies only on liquid properties of the condensate, as an alternative condensation chemistry also induces clustering independent of sumoylation. Our findings introduce a chemical dimerization approach to manipulate phase separation and demonstrate how the material properties and chemical composition of APBs independently contribute to ALT, suggesting a general framework for how chromatin condensates promote cellular functions.
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Affiliation(s)
- Huaiying Zhang
- Departments of Biology, University of Pennsylvania, Philadelphia, PA 19104.,Departments of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
| | - Rongwei Zhao
- Departments of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
| | - Jason Tones
- Departments of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
| | - Michel Liu
- Departments of Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - Robert L Dilley
- Penn Center for Genome Integrity, University of Pennsylvania, Philadelphia, PA 19104
| | - David M Chenoweth
- Department of Cancer Biology, Basser Center for BRCA, Perelman School of Medicine
| | - Roger A Greenberg
- Penn Center for Genome Integrity, University of Pennsylvania, Philadelphia, PA 19104
| | - Michael A Lampson
- Penn Center for Genome Integrity, University of Pennsylvania, Philadelphia, PA 19104
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Zhang JM, Zou L. Alternative lengthening of telomeres: from molecular mechanisms to therapeutic outlooks. Cell Biosci 2020; 10:30. [PMID: 32175073 PMCID: PMC7063710 DOI: 10.1186/s13578-020-00391-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 02/23/2020] [Indexed: 02/06/2023] Open
Abstract
To escape replicative senescence, cancer cells have to overcome telomere attrition during DNA replication. Most of cancers rely on telomerase to extend and maintain telomeres, but 4-11% of cancers use a homologous recombination-based pathway called alternative lengthening of telomeres (ALT). ALT is prevalent in cancers from the mesenchymal origin and usually associates with poor clinical outcome. Given its critical role in protecting telomeres and genomic integrity in tumor cells, ALT is an Achilles heel of tumors and an attractive target for cancer therapy. Here, we review the recent progress in the mechanistic studies of ALT, and discuss the emerging therapeutic strategies to target ALT-positive cancers.
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Affiliation(s)
- Jia-Min Zhang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129 USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129 USA.,2Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 USA
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Zhang JM, Yadav T, Ouyang J, Lan L, Zou L. Alternative Lengthening of Telomeres through Two Distinct Break-Induced Replication Pathways. Cell Rep 2020; 26:955-968.e3. [PMID: 30673617 PMCID: PMC6366628 DOI: 10.1016/j.celrep.2018.12.102] [Citation(s) in RCA: 174] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 11/09/2018] [Accepted: 12/26/2018] [Indexed: 12/11/2022] Open
Abstract
Alternative lengthening of telomeres (ALT) is a telomerase-independent but recombination-dependent pathway that maintains telomeres. Here, we describe an assay to visualize ALT-mediated telomeric DNA synthesis in ALT-associated PML bodies (APBs) without DNA-damaging agents or replication inhibitors. Using this assay, we find that ALT occurs through two distinct mechanisms. One of the ALT mechanisms requires RAD52, a protein implicated in break-induced DNA replication (BIR). We demonstrate that RAD52 directly promotes telomeric D-loop formation in vitro and is required for maintaining telomeres in ALT-positive cells. Unexpectedly, however, RAD52 is dispensable for C-circle formation, a hallmark of ALT. In RAD52-knockout ALT cells, C-circle formation and RAD52-independent ALT DNA synthesis gradually increase as telomeres are shortened, and these activities are dependent on BLM and BIR proteins POLD3 and POLD4. These results suggest that ALT occurs through a RAD52-dependent and a RAD52-independent BIR pathway, revealing the bifurcated framework and dynamic nature of this process.
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Affiliation(s)
- Jia-Min Zhang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Tribhuwan Yadav
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Jian Ouyang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Li Lan
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
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Srinivas N, Rachakonda S, Kumar R. Telomeres and Telomere Length: A General Overview. Cancers (Basel) 2020; 12:E558. [PMID: 32121056 PMCID: PMC7139734 DOI: 10.3390/cancers12030558] [Citation(s) in RCA: 139] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 02/06/2023] Open
Abstract
Telomeres are highly conserved tandem nucleotide repeats that include proximal double-stranded and distal single-stranded regions that in complex with shelterin proteins afford protection at chromosomal ends to maintain genomic integrity. Due to the inherent limitations of DNA replication and telomerase suppression in most somatic cells, telomeres undergo age-dependent incremental attrition. Short or dysfunctional telomeres are recognized as DNA double-stranded breaks, triggering cells to undergo replicative senescence. Telomere shortening, therefore, acts as a counting mechanism that drives replicative senescence by limiting the mitotic potential of cells. Telomere length, a complex hereditary trait, is associated with aging and age-related diseases. Epidemiological data, in general, support an association with varying magnitudes between constitutive telomere length and several disorders, including cancers. Telomere attrition is also influenced by oxidative damage and replicative stress caused by genetic, epigenetic, and environmental factors. Several single nucleotide polymorphisms at different loci, identified through genome-wide association studies, influence inter-individual variation in telomere length. In addition to genetic factors, environmental factors also influence telomere length during growth and development. Telomeres hold potential as biomarkers that reflect the genetic predisposition together with the impact of environmental conditions and as targets for anti-cancer therapies.
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Affiliation(s)
| | | | - Rajiv Kumar
- Division of Functional Genome Analysis, German Cancer Research Center, Im Neunheimer Feld 580, 69120 Heidelberg, Germany; (N.S.); (S.R.)
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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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