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Martin A, Schabort J, Bartke-Croughan R, Tran S, Preetham A, Lu R, Ho R, Gao J, Jenkins S, Boyle J, Ghanim GE, Jagota M, Song YS, Li H, Hockemeyer D. Active telomere elongation by a subclass of cancer-associated POT1 mutations. Genes Dev 2025; 39:445-462. [PMID: 40015989 PMCID: PMC11960693 DOI: 10.1101/gad.352492.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2024] [Accepted: 01/27/2025] [Indexed: 03/01/2025]
Abstract
Mutations in the shelterin protein POT1 are associated with diverse cancers and thought to drive carcinogenesis by impairing POT1's suppression of aberrant telomere elongation. To classify clinical variants of uncertain significance (VUSs) and identify cancer-driving loss-of-function mutations, we developed a locally haploid human stem cell system to evaluate >1900 POT1 mutations, including >600 VUSs. Unexpectedly, many validated familial cancer-associated POT1 (caPOT1) mutations are haplosufficient for cellular viability, indicating that some pathogenic alleles do not act through a loss-of-function mechanism. Instead, POT1's DNA damage response suppression and telomere length control are genetically separable. ATR inhibition enables isolation of frameshift mutants, demonstrating that the only essential function of POT1 is to repress ATR. Furthermore, comparison of caPOT1 and frameshift alleles reveals a class of caPOT1 mutations that elongate telomeres more rapidly than full loss-of-function alleles. This telomere length-promoting activity is independent from POT1's role in overhang sequestration and fill-in synthesis.
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Affiliation(s)
- Annika Martin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
| | - Johannes Schabort
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
| | - Rebecca Bartke-Croughan
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
| | - Stella Tran
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
| | - Atul Preetham
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
| | - Robert Lu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
| | - Richard Ho
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
| | - Jianpu Gao
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
| | - Shirin Jenkins
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
| | - John Boyle
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
| | - George E Ghanim
- MRC Laboratory of Molecular Biology; Cambridge CB2 0QH, United Kingdom
| | - Milind Jagota
- Computer Science Division, University of California, Berkeley, Berkeley, California 94720, USA
| | - Yun S Song
- Computer Science Division, University of California, Berkeley, Berkeley, California 94720, USA
- Department of Statistics, University of California, Berkeley, Berkeley, California 94720, USA
| | - Hanqin Li
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA;
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, California 94720, USA
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA;
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, California 94720, USA
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2
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Rubtsova MP, Nikishin DA, Vyssokikh MY, Koriagina MS, Vasiliev AV, Dontsova OA. Telomere Reprogramming and Cellular Metabolism: Is There a Link? Int J Mol Sci 2024; 25:10500. [PMID: 39408829 PMCID: PMC11476947 DOI: 10.3390/ijms251910500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2024] [Revised: 09/26/2024] [Accepted: 09/27/2024] [Indexed: 10/20/2024] Open
Abstract
Telomeres-special DNA-protein structures at the ends of linear eukaryotic chromosomes-define the proliferation potential of cells. Extremely short telomeres promote a DNA damage response and cell death to eliminate cells that may have accumulated mutations after multiple divisions. However, telomere elongation is associated with the increased proliferative potential of specific cell types, such as stem and germ cells. This elongation can be permanent in these cells and is activated temporally during immune response activation and regeneration processes. The activation of telomere lengthening mechanisms is coupled with increased proliferation and the cells' need for energy and building resources. To obtain the necessary nutrients, cells are capable of finely regulating energy production and consumption, switching between catabolic and anabolic processes. In this review, we focused on the interconnection between metabolism programs and telomere lengthening mechanisms during programmed activation of proliferation, such as in germ cell maturation, early embryonic development, neoplastic lesion growth, and immune response activation. It is generally accepted that telomere disturbance influences biological processes and promotes dysfunctionality. Here, we propose that metabolic conditions within proliferating cells should be involved in regulating telomere lengthening mechanisms, and telomere length may serve as a marker of defects in cellular functionality. We propose that it is possible to reprogram metabolism in order to regulate the telomere length and proliferative activity of cells, which may be important for the development of approaches to regeneration, immune response modulation, and cancer therapy. However, further investigations in this area are necessary to improve the understanding and manipulation of the molecular mechanisms involved in the regulation of proliferation, metabolism, and aging.
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Affiliation(s)
- Maria P. Rubtsova
- Chemistry Department, Lomonosov Moscow State University, Moscow 119234, Russia; (M.S.K.); (O.A.D.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117437, Russia
| | - Denis A. Nikishin
- Department of Embryology, Faculty of Biology, Lomonosov Moscow State University, Moscow 119234, Russia; (D.A.N.); (A.V.V.)
| | - Mikhail Y. Vyssokikh
- A.N.Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia;
| | - Maria S. Koriagina
- Chemistry Department, Lomonosov Moscow State University, Moscow 119234, Russia; (M.S.K.); (O.A.D.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117437, Russia
| | - Andrey V. Vasiliev
- Department of Embryology, Faculty of Biology, Lomonosov Moscow State University, Moscow 119234, Russia; (D.A.N.); (A.V.V.)
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Olga A. Dontsova
- Chemistry Department, Lomonosov Moscow State University, Moscow 119234, Russia; (M.S.K.); (O.A.D.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117437, Russia
- A.N.Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia;
- Skolkovo Institute of Science and Technology, Center for Molecular and Cellular Biology, Moscow 121205, Russia
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Martin A, Schabort J, Bartke-Croughan R, Tran S, Preetham A, Lu R, Ho R, Gao J, Jenkins S, Boyle J, Ghanim GE, Jagota M, Song YS, Li H, Hockemeyer D. Dissecting the oncogenic mechanisms of POT1 cancer mutations through deep scanning mutagenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.19.608636. [PMID: 39229243 PMCID: PMC11370387 DOI: 10.1101/2024.08.19.608636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Mutations in the shelterin protein POT1 are associated with diverse cancers, but their role in cancer progression remains unclear. To resolve this, we performed deep scanning mutagenesis in POT1 locally haploid human stem cells to assess the impact of POT1 variants on cellular viability and cancer-associated telomeric phenotypes. Though POT1 is essential, frame-shift mutants are rescued by chemical ATR inhibition, indicating that POT1 is not required for telomere replication or lagging strand synthesis. In contrast, a substantial fraction of clinically-validated pathogenic mutations support normal cellular proliferation, but still drive ATR-dependent telomeric DNA damage signaling and ATR-independent telomere elongation. Moreover, this class of cancer-associated POT1 variants elongates telomeres more rapidly than POT1 frame-shifts, indicating they actively drive oncogenesis and are not simple loss-of-function mutations.
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4
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Kallingal A, Krzemieniecki R, Maciejewska N, Brankiewicz-Kopcińska W, Baginski M. TRF1 and TRF2: pioneering targets in telomere-based cancer therapy. J Cancer Res Clin Oncol 2024; 150:353. [PMID: 39012375 PMCID: PMC11252209 DOI: 10.1007/s00432-024-05867-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 06/25/2024] [Indexed: 07/17/2024]
Abstract
This article presents an in-depth exploration of the roles of Telomere Repeat-binding Factors 1 and 2 (TRF1 and TRF2), and the shelterin complex, in the context of cancer biology. It emphasizes their emerging significance as potential biomarkers and targets for therapeutic intervention. Central to the shelterin complex, TRF1 and TRF2 are crucial in maintaining telomere integrity and genomic stability, their dysregulation often being a hallmark of cancerous cells. The article delves into the diagnostic and prognostic capabilities of TRF1 and TRF2 across various cancer types, highlighting their sensitivity and specificity. Furthermore, it reviews current strides in drug discovery targeting the shelterin complex, detailing specific compounds and their modes of action. The review candidly addresses the challenges in developing therapies aimed at the shelterin complex, including drug resistance, off-target effects, and issues in drug delivery. By synthesizing recent research findings, the article sheds light on the intricate relationship between telomere biology and cancer development. It underscores the urgency for continued research to navigate the existing challenges and fully leverage the therapeutic potential of TRF1, TRF2, and the shelterin complex in the realm of cancer treatment.
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Affiliation(s)
- Anoop Kallingal
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Gdansk, 80-233, Poland.
| | - Radosław Krzemieniecki
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Gdansk, 80-233, Poland
| | - Natalia Maciejewska
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Gdansk, 80-233, Poland
| | | | - Maciej Baginski
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Gdansk, 80-233, Poland
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Shoeb M, Meighan T, Kodali VK, Abadin H, Faroon O, Zarus GM, Erdely A, Antonini JM. TERT-independent telomere elongation and shelterin dysregulation after pulmonary exposure to stainless-steel welding fume in-vivo. ENVIRONMENTAL RESEARCH 2024; 250:118515. [PMID: 38373547 PMCID: PMC11375608 DOI: 10.1016/j.envres.2024.118515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/16/2024] [Accepted: 02/16/2024] [Indexed: 02/21/2024]
Abstract
Telomeres are inert DNA sequences (TTAGGG) at the end of chromosomes that protect genetic information and maintain DNA integrity. Emerging evidence has demonstrated that telomere alteration can be closely related to occupational exposure and the development of various disease conditions, including cancer. However, the functions and underlying molecular mechanisms of telomere alteration and shelterin dysregulation after welding fume exposures have not been broadly defined. In this study, we analyzed telomere length and shelterin complex proteins in peripheral blood mononuclear cells (PBMCs) and in lung tissue recovered from male Sprague-Dawley rats following exposure by intratracheal instillation (ITI) to 2 mg/rat of manual metal arc-stainless steel (MMA-SS) welding fume particulate or saline (vehicle control). PBMCs and lung tissue were harvested at 30 d after instillation. Our study identified telomere elongation and shelterin dysregulation in PBMCs and lung tissue after welding fume exposure. Mechanistically, telomere elongation was independent of telomerase reverse transcriptase (TERT) activation. Collectively, our findings demonstrated that welding fume-induced telomere elongation was (a) TERT-independent and (b) associated with shelterin complex dysregulation. It is possible that an alteration of telomere length and its regulatory proteins may be utilized as predictive biomarkers for various disease conditions after welding fume exposure. This needs further investigation.
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Affiliation(s)
- Mohammad Shoeb
- Office of Innovation and Analytics, Agency for Toxic Substances and Disease Registry (ATSDR), Centers for Disease Control and Prevention (CDC), 4770 Buford Highway, Mailstop S106-5, Chamblee, GA, 30341, USA.
| | - Terence Meighan
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
| | - Vamsi K Kodali
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
| | - Henry Abadin
- Office of Innovation and Analytics, Agency for Toxic Substances and Disease Registry (ATSDR), Centers for Disease Control and Prevention (CDC), 4770 Buford Highway, Mailstop S106-5, Chamblee, GA, 30341, USA
| | - Obaid Faroon
- Office of Innovation and Analytics, Agency for Toxic Substances and Disease Registry (ATSDR), Centers for Disease Control and Prevention (CDC), 4770 Buford Highway, Mailstop S106-5, Chamblee, GA, 30341, USA
| | - Gregory M Zarus
- Office of Innovation and Analytics, Agency for Toxic Substances and Disease Registry (ATSDR), Centers for Disease Control and Prevention (CDC), 4770 Buford Highway, Mailstop S106-5, Chamblee, GA, 30341, USA
| | - Aaron Erdely
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
| | - James M Antonini
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
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Carvalho Borges PC, Bouabboune C, Escandell JM, Matmati S, Coulon S, Ferreira MG. Pot1 promotes telomere DNA replication via the Stn1-Ten1 complex in fission yeast. Nucleic Acids Res 2023; 51:12325-12336. [PMID: 37953281 PMCID: PMC10711446 DOI: 10.1093/nar/gkad1036] [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: 01/20/2023] [Revised: 10/19/2023] [Accepted: 10/31/2023] [Indexed: 11/14/2023] Open
Abstract
Telomeres are nucleoprotein complexes that protect the chromosome-ends from eliciting DNA repair while ensuring their complete duplication. Pot1 is a subunit of telomere capping complex that binds to the G-rich overhang and inhibits the activation of DNA damage checkpoints. In this study, we explore new functions of fission yeast Pot1 by using a pot1-1 temperature sensitive mutant. We show that pot1 inactivation impairs telomere DNA replication resulting in the accumulation of ssDNA leading to the complete loss of telomeric DNA. Recruitment of Stn1 to telomeres, an auxiliary factor of DNA lagging strand synthesis, is reduced in pot1-1 mutants and overexpression of Stn1 rescues loss of telomeres and cell viability at restrictive temperature. We propose that Pot1 plays a crucial function in telomere DNA replication by recruiting Stn1-Ten1 and Polα-primase complex to telomeres via Tpz1, thus promoting lagging-strand DNA synthesis at stalled replication forks.
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Affiliation(s)
| | - Chaïnez Bouabboune
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Equipe labellisée par la Ligue Nationale contre le Cancer, Marseille, F-13009, France
| | | | - Samah Matmati
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Equipe labellisée par la Ligue Nationale contre le Cancer, Marseille, F-13009, France
| | - Stéphane Coulon
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Equipe labellisée par la Ligue Nationale contre le Cancer, Marseille, F-13009, France
| | - Miguel Godinho Ferreira
- Instituto Gulbenkian de Ciência, Oeiras, 2781-901, Portugal
- Institute for Research on Cancer and Aging of Nice (IRCAN), INSERM U1081 UMR7284 CNRS, 06107 Nice, France
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Li B. Telomere maintenance in African trypanosomes. Front Mol Biosci 2023; 10:1302557. [PMID: 38074093 PMCID: PMC10704157 DOI: 10.3389/fmolb.2023.1302557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/15/2023] [Indexed: 02/12/2024] Open
Abstract
Telomere maintenance is essential for genome integrity and chromosome stability in eukaryotic cells harboring linear chromosomes, as telomere forms a specialized structure to mask the natural chromosome ends from DNA damage repair machineries and to prevent nucleolytic degradation of the telomeric DNA. In Trypanosoma brucei and several other microbial pathogens, virulence genes involved in antigenic variation, a key pathogenesis mechanism essential for host immune evasion and long-term infections, are located at subtelomeres, and expression and switching of these major surface antigens are regulated by telomere proteins and the telomere structure. Therefore, understanding telomere maintenance mechanisms and how these pathogens achieve a balance between stability and plasticity at telomere/subtelomere will help develop better means to eradicate human diseases caused by these pathogens. Telomere replication faces several challenges, and the "end replication problem" is a key obstacle that can cause progressive telomere shortening in proliferating cells. To overcome this challenge, most eukaryotes use telomerase to extend the G-rich telomere strand. In addition, a number of telomere proteins use sophisticated mechanisms to coordinate the telomerase-mediated de novo telomere G-strand synthesis and the telomere C-strand fill-in, which has been extensively studied in mammalian cells. However, we recently discovered that trypanosomes lack many telomere proteins identified in its mammalian host that are critical for telomere end processing. Rather, T. brucei uses a unique DNA polymerase, PolIE that belongs to the DNA polymerase A family (E. coli DNA PolI family), to coordinate the telomere G- and C-strand syntheses. In this review, I will first briefly summarize current understanding of telomere end processing in mammals. Subsequently, I will describe PolIE-mediated coordination of telomere G- and C-strand synthesis in T. brucei and implication of this recent discovery.
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Affiliation(s)
- Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Arts and Sciences, Cleveland State University, Cleveland, OH, United States
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, United States
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
- Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, OH, United States
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Li Q, Wang X, Liu J, Wu L, Xu S. POT1 involved in telomeric DNA damage repair and genomic stability of cervical cancer cells in response to radiation. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2023; 891:503670. [PMID: 37770150 DOI: 10.1016/j.mrgentox.2023.503670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 07/25/2023] [Accepted: 08/05/2023] [Indexed: 10/03/2023]
Abstract
Though telomeres play a crucial role in maintaining genomic stability in cancer cells and have emerged as attractive therapeutic targets in anticancer therapy, the relationship between telomere dysfunction and genomic instability induced by irradiation is still unclear. In this study, we identified that protection of telomeres 1 (POT1), a single-stranded DNA (ssDNA)-binding protein, was upregulated in γ-irradiated HeLa cells and in cancer patients who exhibit radiation tolerance. Knockdown of POT1 delayed the repair of radiation-induced telomeric DNA damage which was associated with enhanced H3K9 trimethylation and enhanced the radiosensitivity of HeLa cells. The depletion of POT1 also resulted in significant genomic instability, by showing a significant increase in end-to-end chromosomal fusions, and the formation of anaphase bridges and micronuclei. Furthermore, knockdown of POT1 disturbed telomerase recruitment to telomere, and POT1 could interact with phosphorylated ATM (p-ATM) and POT1 depletion decreased the levels of p-ATM induced by irradiation, suggesting that POT1 could regulate the telomerase recruitment to telomeres to repair irradiation-induced telomeric DNA damage of HeLa cells through interactions with p-ATM. The enhancement of radiosensitivity in cancer cells can be achieved through the combination of POT1 and telomerase inhibitors, presenting a potential approach for radiotherapy in cancer treatment.
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Affiliation(s)
- Qian Li
- School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, PR China
| | - Xiaofei Wang
- School of Biology, Food and Environment, Hefei University, Hefei 230601, PR China
| | - Jie Liu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, PR China
| | - Lijun Wu
- School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, PR China; Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, PR China.
| | - Shengmin Xu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, PR China.
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Bhat GR, Jamwal RS, Sethi I, Bhat A, Shah R, Verma S, Sharma M, Sadida HQ, Al-Marzooqi SK, Masoodi T, Mirza S, Haris M, Macha MA, Akil ASA, Bhat AA, Kumar R. Associations between telomere attrition, genetic variants in telomere maintenance genes, and non-small cell lung cancer risk in the Jammu and Kashmir population of North India. BMC Cancer 2023; 23:874. [PMID: 37718447 PMCID: PMC10506276 DOI: 10.1186/s12885-023-11387-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 09/07/2023] [Indexed: 09/19/2023] Open
Abstract
BACKGROUND Telomeres are repetitive DNA sequences located at the ends of chromosomes, playing a vital role in maintaining chromosomal integrity and stability. Dysregulation of telomeres has been implicated in the development of various cancers, including non-small cell lung cancer (NSCLC), which is the most common type of lung cancer. Genetic variations within telomere maintenance genes may influence the risk of developing NSCLC. The present study aimed to evaluate the genetic associations of select variants within telomere maintenance genes in a population from Jammu and Kashmir, North India, and to investigate the relationship between telomere length and NSCLC risk. METHODS We employed the cost-effective and high-throughput MassARRAY MALDI-TOF platform to assess the genetic associations of select variants within telomere maintenance genes in a population from Jammu and Kashmir, North India. Additionally, we used TaqMan genotyping to validate our results. Furthermore, we investigated telomere length variation and its relation to NSCLC risk in the same population using dual-labeled fluorescence-based qPCR. RESULTS Our findings revealed significant associations of TERT rs10069690 and POT1 rs10228682 with NSCLC risk (adjusted p-values = 0.019 and 0.002, respectively), while TERF2 rs251796 and rs2975843 showed no significant associations. The TaqMan genotyping validation further substantiated the associations of TERT rs10069690 and rs2242652 with NSCLC risk (adjusted p-values = 0.02 and 0.003, respectively). Our results also demonstrated significantly shorter telomere lengths in NSCLC patients compared to controls (p = 0.0004). CONCLUSION This study highlights the crucial interplay between genetic variation in telomere maintenance genes, telomere attrition, and NSCLC risk in the Jammu and Kashmir population of North India. Our findings suggest that TERT and POT1 gene variants, along with telomere length, may serve as potential biomarkers and therapeutic targets for NSCLC in this population. Further research is warranted to elucidate the underlying mechanisms and to explore the potential clinical applications of these findings.
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Affiliation(s)
- Gh Rasool Bhat
- School of Biotechnology, Shri Mata Vaishno Devi University, Katra, Jammu and Kashmir, 182320, India
| | - Rajeshwer Singh Jamwal
- School of Biotechnology, Shri Mata Vaishno Devi University, Katra, Jammu and Kashmir, 182320, India
| | - Itty Sethi
- Institute of Human Genetics, University of Jammu, Jammu and Kashmir, 180001, India
| | - Amrita Bhat
- Institute of Human Genetics, University of Jammu, Jammu and Kashmir, 180001, India
| | - Ruchi Shah
- School of Biotechnology, Shri Mata Vaishno Devi University, Katra, Jammu and Kashmir, 182320, India
| | - Sonali Verma
- School of Biotechnology, Shri Mata Vaishno Devi University, Katra, Jammu and Kashmir, 182320, India
| | - Minerva Sharma
- School of Biotechnology, Shri Mata Vaishno Devi University, Katra, Jammu and Kashmir, 182320, India
| | - Hana Q Sadida
- Department of Human Genetics-Precision Medicine in Diabetes, Obesity & Cancer Program, Sidra Medicine, 26999, Doha, Qatar
| | - Sara K Al-Marzooqi
- Department of Human Genetics-Precision Medicine in Diabetes, Obesity & Cancer Program, Sidra Medicine, 26999, Doha, Qatar
| | - Tariq Masoodi
- Laboratory of Cancer Immunology and Genetics, Sidra Medicine, 26999, Doha, Qatar
| | - Sameer Mirza
- Department of Chemistry, College of Sciences, United Arab , Emirates University, 15551, Al-Ain, United Arab Emirates
| | - Mohammad Haris
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | - Muzafar A Macha
- Watson-Crick Centre for Molecular Medicine, Islamic University of Science and Technology, 192122, Jammu and Kashmir, India
| | - Ammira S Alshabeeb Akil
- Department of Human Genetics-Precision Medicine in Diabetes, Obesity & Cancer Program, Sidra Medicine, 26999, Doha, Qatar
| | - Ajaz A Bhat
- Department of Human Genetics-Precision Medicine in Diabetes, Obesity & Cancer Program, Sidra Medicine, 26999, Doha, Qatar.
| | - Rakesh Kumar
- School of Biotechnology, Shri Mata Vaishno Devi University, Katra, Jammu and Kashmir, 182320, India.
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10
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Wolf SE, Shalev I. The shelterin protein expansion of telomere dynamics: Linking early life adversity, life history, and the hallmarks of aging. Neurosci Biobehav Rev 2023; 152:105261. [PMID: 37268182 PMCID: PMC10527177 DOI: 10.1016/j.neubiorev.2023.105261] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 04/10/2023] [Accepted: 05/30/2023] [Indexed: 06/04/2023]
Abstract
Aging is characterized by functional decline occurring alongside changes to several hallmarks of aging. One of the hallmarks includes attrition of repeated DNA sequences found at the ends of chromosomes called telomeres. While telomere attrition is linked to morbidity and mortality, whether and how it causally contributes to lifelong rates of functional decline is unclear. In this review, we propose the shelterin-telomere hypothesis of life history, in which telomere-binding shelterin proteins translate telomere attrition into a range of physiological outcomes, the extent of which may be modulated by currently understudied variation in shelterin protein levels. Shelterin proteins may expand the breadth and timing of consequences of telomere attrition, e.g., by translating early life adversity into acceleration of the aging process. We consider how the pleiotropic roles of shelterin proteins provide novel insights into natural variation in physiology, life history, and lifespan. We highlight key open questions that encourage the integrative, organismal study of shelterin proteins that enhances our understanding of the contribution of the telomere system to aging.
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Affiliation(s)
- Sarah E Wolf
- Department of Biobehavioral Health, Penn State University, University Park, PA 16802, USA.
| | - Idan Shalev
- Department of Biobehavioral Health, Penn State University, University Park, PA 16802, USA
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11
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Tesmer VM, Brenner KA, Nandakumar J. Human POT1 protects the telomeric ds-ss DNA junction by capping the 5' end of the chromosome. Science 2023; 381:771-778. [PMID: 37590346 PMCID: PMC10666826 DOI: 10.1126/science.adi2436] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/19/2023] [Indexed: 08/19/2023]
Abstract
Protection of telomeres 1 (POT1) is the 3' single-stranded overhang-binding telomeric protein that prevents an ataxia telangiectasia and Rad3-related (ATR) DNA damage response (DDR) at chromosome ends. What precludes the DDR machinery from accessing the telomeric double-stranded-single-stranded junction is unknown. We demonstrate that human POT1 binds this junction by recognizing the phosphorylated 5' end of the chromosome. High-resolution crystallographic structures reveal that the junction is capped by POT1 through a "POT-hole" surface, the mutation of which compromises junction protection in vitro and telomeric 5'-end definition and DDR suppression in human cells. Whereas both mouse POT1 paralogs bind the single-stranded overhang, POT1a, not POT1b, contains a POT-hole and binds the junction, which explains POT1a's sufficiency for end protection. Our study shifts the paradigm for DDR suppression at telomeres by highlighting the importance of protecting the double-stranded-single-stranded junction.
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Affiliation(s)
- Valerie M. Tesmer
- Department of Molecular, Cellular and Developmental Biology, University of Michigan; Ann Arbor, 48109, USA
| | - Kirsten A. Brenner
- Department of Molecular, Cellular and Developmental Biology, University of Michigan; Ann Arbor, 48109, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular and Developmental Biology, University of Michigan; Ann Arbor, 48109, USA
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12
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Zade NH, Khattar E. POT1 mutations cause differential effects on telomere length leading to opposing disease phenotypes. J Cell Physiol 2023; 238:1237-1255. [PMID: 37183325 DOI: 10.1002/jcp.31034] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 03/28/2023] [Accepted: 04/17/2023] [Indexed: 05/16/2023]
Abstract
The protection of telomere protein (POT1) is a telomere-binding protein and is an essential component of the six-membered shelterin complex, which is associated with the telomeres. POT1 directly binds to the 3' single-stranded telomeric overhang and prevents the activation of DNA damage response at telomeres thus preventing the telomere-telomere fusions and genomic instability. POT1 also plays a pivotal role in maintaining telomere length by regulating telomerase-mediated telomere elongation. Mutations in POT1 proteins result in three different telomere phenotypes, which include long, short, or aberrant telomere length. Long telomeres predispose individuals to cancer, while short or aberrant telomere phenotypes result in pro-aging diseases referred to as telomeropathies. Here, we review the function of POT1 proteins in telomere length hemostasis and how the spectrum of mutations reported in POT1 can be segregated toward developing very distinct disease phenotypes of cancer and telomeropathies.
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Affiliation(s)
- Nikita Harish Zade
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be) University, Mumbai, India
| | - Ekta Khattar
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be) University, Mumbai, India
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13
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A non-genetic switch triggers alternative telomere lengthening and cellular immortalization in ATRX deficient cells. Nat Commun 2023; 14:939. [PMID: 36805596 PMCID: PMC9941109 DOI: 10.1038/s41467-023-36294-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 01/25/2023] [Indexed: 02/22/2023] Open
Abstract
Alternative Lengthening of Telomeres (ALT) is an aberrant DNA recombination pathway which grants replicative immortality to approximately 10% of all cancers. Despite this high prevalence of ALT in cancer, the mechanism and genetics by which cells activate this pathway remain incompletely understood. A major challenge in dissecting the events that initiate ALT is the extremely low frequency of ALT induction in human cell systems. Guided by the genetic lesions that have been associated with ALT from cancer sequencing studies, we genetically engineered primary human pluripotent stem cells to deterministically induce ALT upon differentiation. Using this genetically defined system, we demonstrate that disruption of the p53 and Rb pathways in combination with ATRX loss-of-function is sufficient to induce all hallmarks of ALT and results in functional immortalization in a cell type-specific manner. We further demonstrate that ALT can be induced in the presence of telomerase, is neither dependent on telomere shortening nor crisis, but is rather driven by continuous telomere instability triggered by the induction of differentiation in ATRX-deficient stem cells.
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14
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Barnes RP, Thosar SA, Opresko PL. Telomere Fragility and MiDAS: Managing the Gaps at the End of the Road. Genes (Basel) 2023; 14:genes14020348. [PMID: 36833275 PMCID: PMC9956152 DOI: 10.3390/genes14020348] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/20/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
Telomeres present inherent difficulties to the DNA replication machinery due to their repetitive sequence content, formation of non-B DNA secondary structures, and the presence of the nucleo-protein t-loop. Especially in cancer cells, telomeres are hot spots for replication stress, which can result in a visible phenotype in metaphase cells termed "telomere fragility". A mechanism cells employ to mitigate replication stress, including at telomeres, is DNA synthesis in mitosis (MiDAS). While these phenomena are both observed in mitotic cells, the relationship between them is poorly understood; however, a common link is DNA replication stress. In this review, we will summarize what is known to regulate telomere fragility and telomere MiDAS, paying special attention to the proteins which play a role in these telomere phenotypes.
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Affiliation(s)
- Ryan P. Barnes
- Department of Environmental and Occupational Health, School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
- UPMC Hillman Cancer Center, University of Pittsburgh, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
- Correspondence: (R.P.B.); (P.L.O.)
| | - Sanjana A. Thosar
- Department of Environmental and Occupational Health, School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
- UPMC Hillman Cancer Center, University of Pittsburgh, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
| | - Patricia L. Opresko
- Department of Environmental and Occupational Health, School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
- UPMC Hillman Cancer Center, University of Pittsburgh, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Correspondence: (R.P.B.); (P.L.O.)
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15
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Fanelli A, Marconato L, Licenziato L, Minoli L, Rouquet N, Aresu L. POT1 mutations are frequent and associated with Ki-67 index in canine diffuse large B-cell lymphoma. Front Vet Sci 2022; 9:968807. [PMID: 36016811 PMCID: PMC9396242 DOI: 10.3389/fvets.2022.968807] [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: 06/14/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Diffuse large B-cell lymphoma (DLBCL) represents one of the most frequent and deadliest neoplasia in dogs worldwide and is characterized by a remarkable degree of clinical heterogeneity, with poor chances to anticipate the outcome. Even if in the last years some recurrently mutated genes have been identified, the genetic origin of canine DLBCL (cDLBCL) is not yet completely understood. The aim of the present study was to assess the prevalence of POT1 mutations in cDLBCL and to elucidate the role of such gene in the pathogenesis of this tumor. Mutations in POT1 were retrieved in 34% of cases, in line with previous reports, but no significant associations with any clinico-pathological variable were identified. Likewise, POT1 mutations are not predictive of worse prognosis. Interestingly, Ki-67 index was significantly higher in dogs harboring POT1 mutations compared to wild-type ones. These results suggest that POT1 mutations may exert their pathogenic role in cDLBCL by promoting cellular proliferation.
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Affiliation(s)
- Antonella Fanelli
- Department of Veterinary Sciences, University of Turin, Turin, Italy
- *Correspondence: Antonella Fanelli
| | - Laura Marconato
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
| | - Luca Licenziato
- Department of Veterinary Sciences, University of Turin, Turin, Italy
| | - Lucia Minoli
- Department of Veterinary Sciences, University of Turin, Turin, Italy
| | | | - Luca Aresu
- Department of Veterinary Sciences, University of Turin, Turin, Italy
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16
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Zahid S, Aloe S, Sutherland JH, Holloman WK, Lue NF. Ustilago maydis telomere protein Pot1 harbors an extra N-terminal OB fold and regulates homology-directed DNA repair factors in a dichotomous and context-dependent manner. PLoS Genet 2022; 18:e1010182. [PMID: 35587917 PMCID: PMC9119445 DOI: 10.1371/journal.pgen.1010182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 04/02/2022] [Indexed: 01/11/2023] Open
Abstract
The telomere G-strand binding protein Pot1 plays multifaceted roles in telomere maintenance and protection. We examined the structure and activities of Pot1 in Ustilago maydis, a fungal model that recapitulates key features of mammalian telomere regulation. Compared to the well-characterized primate and fission yeast Pot1 orthologs, UmPot1 harbors an extra N-terminal OB-fold domain (OB-N), which was recently shown to be present in most metazoans. UmPot1 binds directly to Rad51 and regulates the latter's strand exchange activity. Deleting the OB-N domain, which is implicated in Rad51-binding, caused telomere shortening, suggesting that Pot1-Rad51 interaction facilitates telomere maintenance. Depleting Pot1 through transcriptional repression triggered growth arrest as well as rampant recombination, leading to multiple telomere aberrations. In addition, telomere repeat RNAs transcribed from both the G- and C-strand were dramatically up-regulated, and this was accompanied by elevated levels of telomere RNA-DNA hybrids. Telomere abnormalities of pot1-deficient cells were suppressed, and cell viability was restored by the deletion of genes encoding Rad51 or Brh2 (the BRCA2 ortholog), indicating that homology-directed repair (HDR) proteins are key mediators of telomere aberrations and cellular toxicity. Together, these observations underscore the complex physical and functional interactions between Pot1 and DNA repair factors, leading to context-dependent and dichotomous effects of HDR proteins on telomere maintenance and protection.
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Affiliation(s)
- Syed Zahid
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, New York, New York, United States of America
| | - Sarah Aloe
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, New York, New York, United States of America
| | - Jeanette H. Sutherland
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, New York, New York, United States of America
| | - William K. Holloman
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, New York, New York, United States of America
| | - Neal F. Lue
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, New York, New York, United States of America
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, New York, United States of America
- * E-mail:
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17
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Vertecchi E, Rizzo A, Salvati E. Telomere Targeting Approaches in Cancer: Beyond Length Maintenance. Int J Mol Sci 2022; 23:ijms23073784. [PMID: 35409143 PMCID: PMC8998427 DOI: 10.3390/ijms23073784] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/25/2022] [Accepted: 03/26/2022] [Indexed: 12/19/2022] Open
Abstract
Telomeres are crucial structures that preserve genome stability. Their progressive erosion over numerous DNA duplications determines the senescence of cells and organisms. As telomere length homeostasis is critical for cancer development, nowadays, telomere maintenance mechanisms are established targets in cancer treatment. Besides telomere elongation, telomere dysfunction impinges on intracellular signaling pathways, in particular DNA damage signaling and repair, affecting cancer cell survival and proliferation. This review summarizes and discusses recent findings in anticancer drug development targeting different “telosome” components.
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Affiliation(s)
- Eleonora Vertecchi
- Institute of Molecular Biology and Pathology, National Research Council, Rome, Italy, c/o Department of Biology and Biotechnology, Sapienza University of Rome, Via degli Apuli 4, 00185 Rome, Italy;
| | - Angela Rizzo
- Oncogenomic and Epigenetic Unit, IRCCS Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144 Rome, Italy;
| | - Erica Salvati
- Institute of Molecular Biology and Pathology, National Research Council, Rome, Italy, c/o Department of Biology and Biotechnology, Sapienza University of Rome, Via degli Apuli 4, 00185 Rome, Italy;
- Correspondence:
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18
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Ghadaouia S, Olivier MA, Martinez A, Kientega T, Qin J, Lambert-Lanteigne P, Cardin GB, Autexier C, Malaquin N, Rodier F. Homologous recombination-mediated irreversible genome damage underlies telomere-induced senescence. Nucleic Acids Res 2021; 49:11690-11707. [PMID: 34725692 PMCID: PMC8599762 DOI: 10.1093/nar/gkab965] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/28/2021] [Accepted: 10/12/2021] [Indexed: 12/12/2022] Open
Abstract
Loss of telomeric DNA leads to telomere uncapping, which triggers a persistent, p53-centric DNA damage response that sustains a stable senescence-associated proliferation arrest. Here, we show that in normal cells telomere uncapping triggers a focal telomeric DNA damage response accompanied by a transient cell cycle arrest. Subsequent cell division with dysfunctional telomeres resulted in sporadic telomeric sister chromatid fusions that gave rise to next-mitosis genome instability, including non-telomeric DNA lesions responsible for a stable, p53-mediated, senescence-associated proliferation arrest. Unexpectedly, the blocking of Rad51/RPA-mediated homologous recombination, but not non-homologous end joining (NHEJ), prevented senescence despite multiple dysfunctional telomeres. When cells approached natural replicative senescence, interphase senescent cells displayed genome instability, whereas near-senescent cells that underwent mitosis despite the presence of uncapped telomeres did not. This suggests that these near-senescent cells had not yet acquired irreversible telomeric fusions. We propose a new model for telomere-initiated senescence where tolerance of telomere uncapping eventually results in irreversible non-telomeric DNA lesions leading to stable senescence. Paradoxically, our work reveals that senescence-associated tumor suppression from telomere shortening requires irreversible genome instability at the single-cell level, which suggests that interventions to repair telomeres in the pre-senescent state could prevent senescence and genome instability.
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Affiliation(s)
- Sabrina Ghadaouia
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada.,Institut du cancer de Montréal, Montreal, QC, H2X 0A9, Canada
| | - Marc-Alexandre Olivier
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada.,Institut du cancer de Montréal, Montreal, QC, H2X 0A9, Canada
| | - Aurélie Martinez
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada.,Institut du cancer de Montréal, Montreal, QC, H2X 0A9, Canada
| | - Tibila Kientega
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada.,Institut du cancer de Montréal, Montreal, QC, H2X 0A9, Canada
| | - Jian Qin
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, H3A 0C7, Canada.,Jewish General Hospital, Lady Davis Institute, Montreal, QC, H3T 1E2, Canada
| | | | - Guillaume B Cardin
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada.,Institut du cancer de Montréal, Montreal, QC, H2X 0A9, Canada
| | - Chantal Autexier
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, H3A 0C7, Canada.,Jewish General Hospital, Lady Davis Institute, Montreal, QC, H3T 1E2, Canada
| | - Nicolas Malaquin
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada.,Institut du cancer de Montréal, Montreal, QC, H2X 0A9, Canada
| | - Francis Rodier
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada.,Institut du cancer de Montréal, Montreal, QC, H2X 0A9, Canada.,Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montreal, QC, H3T 1J4, Canada
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19
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Robinson NJ, Miyagi M, Scarborough JA, Scott JG, Taylor DJ, Schiemann WP. SLX4IP promotes RAP1 SUMOylation by PIAS1 to coordinate telomere maintenance through NF-κB and Notch signaling. Sci Signal 2021; 14:eabe9613. [PMID: 34187905 PMCID: PMC8353884 DOI: 10.1126/scisignal.abe9613] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The maintenance of telomere length supports repetitive cell division and therefore plays a central role in cancer development and progression. Telomeres are extended by either the enzyme telomerase or the alternative lengthening of telomeres (ALT) pathway. Here, we found that the telomere-associated protein SLX4IP dictates telomere proteome composition by recruiting and activating the E3 SUMO ligase PIAS1 to the SLX4 complex. PIAS1 SUMOylated the telomere-binding protein RAP1, which disrupted its interaction with the telomere-binding protein TRF2 and facilitated its nucleocytoplasmic shuttling. In the cytosol, RAP1 bound to IκB kinase (IKK), resulting in activation of the transcription factor NF-κB and its induction of Jagged-1 expression, which promoted Notch signaling and the institution of ALT. This axis could be targeted therapeutically in ALT-driven cancers and in tumor cells that develop resistance to antitelomerase therapies. Our results illuminate the mechanisms underlying SLX4IP-dependent telomere plasticity and demonstrate the role of telomere proteins in directly coordinating intracellular signaling and telomere maintenance dynamics.
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Affiliation(s)
- Nathaniel J Robinson
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Masaru Miyagi
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Jessica A Scarborough
- Department of Translational Hematology and Oncology Research, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Jacob G Scott
- Department of Translational Hematology and Oncology Research, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Derek J Taylor
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - William P Schiemann
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA.
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20
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Kim WT, Hennick K, Johnson J, Finnerty B, Choo S, Short SB, Drubin C, Forster R, McMaster ML, Hockemeyer D. Cancer-associated POT1 mutations lead to telomere elongation without induction of a DNA damage response. EMBO J 2021; 40:e107346. [PMID: 33934394 PMCID: PMC8204863 DOI: 10.15252/embj.2020107346] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 03/09/2021] [Accepted: 03/16/2021] [Indexed: 12/28/2022] Open
Abstract
Mutations in the shelterin protein POT1 are associated with chronic lymphocytic leukemia (CLL), Hodgkin lymphoma, angiosarcoma, melanoma, and other cancers. These cancer‐associated POT1 (caPOT1) mutations are generally heterozygous, missense, or nonsense mutations occurring throughout the POT1 reading frame. Cancers with caPOT1 mutations have elongated telomeres and show increased genomic instability, but which of the two phenotypes promotes tumorigenesis is unclear. We tested the effects of CAS9‐engineered caPOT1 mutations in human embryonic and hematopoietic stem cells (hESCs and HSCs, respectively). HSCs with caPOT1 mutations did not show overt telomere damage. In vitro and in vivo competition experiments showed the caPOT1 mutations did not confer a selective disadvantage. Since DNA damage signaling is known to affect the fitness of HSCs, the data argue that caPOT1 mutations do not cause significant telomere damage. Furthermore, hESC lines with caPOT1 mutations showed no detectable telomere damage response while showing consistent telomere elongation. Thus, caPOT1 mutations are likely selected for during cancer progression because of their ability to elongate telomeres and extend the proliferative capacity of the incipient cancer cells.
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Affiliation(s)
- Won-Tae Kim
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Kelsey Hennick
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Joshua Johnson
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Brendan Finnerty
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Seunga Choo
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Sarah B Short
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Casey Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Ryan Forster
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Mary L McMaster
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.,Chan Zuckerberg Biohub, San Francisco, CA, USA.,Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
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21
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Shoeb M, Meier HCS, Antonini JM. Telomeres in toxicology: Occupational health. Pharmacol Ther 2021; 220:107742. [PMID: 33176178 PMCID: PMC7969441 DOI: 10.1016/j.pharmthera.2020.107742] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/03/2020] [Indexed: 12/24/2022]
Abstract
The ends of chromosomes shorten at each round of cell division, and this process is thought to be affected by occupational exposures. Occupational hazards may alter telomere length homeostasis resulting in DNA damage, chromosome aberration, mutations, epigenetic alterations and inflammation. Therefore, for the protection of genetic material, nature has provided a unique nucleoprotein structure known as a telomere. Telomeres provide protection by averting an inappropriate activation of the DNA damage response (DDR) at chromosomal ends and preventing recognition of single and double strand DNA (ssDNA and dsDNA) breaks or chromosomal end-to-end fusion. Telomeres and their interacting six shelterin complex proteins in coordination act as inhibitors of DNA damage machinery by blocking DDR activation at chromosomes, thereby preventing the occurrence of genome instability, perturbed cell cycle, cellular senescence and apoptosis. However, inappropriate DNA repair may result in the inadequate distribution of genetic material during cell division, resulting in the eventual development of tumorigenesis and other pathologies. This article reviews the current literature on the association of changes in telomere length and its interacting proteins with different occupational exposures and the potential application of telomere length or changes in the regulatory proteins as potential biomarkers for exposure and health response, including recent findings and future perspectives.
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Affiliation(s)
- Mohammad Shoeb
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, United States of America.
| | - Helen C S Meier
- Joseph J. Zilber School of Public Health, University of Wisconsin, Milwaukee, WI, United States of America
| | - James M Antonini
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, United States of America
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22
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Lim CJ, Cech TR. Shaping human telomeres: from shelterin and CST complexes to telomeric chromatin organization. Nat Rev Mol Cell Biol 2021; 22:283-298. [PMID: 33564154 DOI: 10.1038/s41580-021-00328-y] [Citation(s) in RCA: 153] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2021] [Indexed: 01/14/2023]
Abstract
The regulation of telomere length in mammals is crucial for chromosome end-capping and thus for maintaining genome stability and cellular lifespan. This process requires coordination between telomeric protein complexes and the ribonucleoprotein telomerase, which extends the telomeric DNA. Telomeric proteins modulate telomere architecture, recruit telomerase to accessible telomeres and orchestrate the conversion of the newly synthesized telomeric single-stranded DNA tail into double-stranded DNA. Dysfunctional telomere maintenance leads to telomere shortening, which causes human diseases including bone marrow failure, premature ageing and cancer. Recent studies provide new insights into telomerase-related interactions (the 'telomere replisome') and reveal new challenges for future telomere structural biology endeavours owing to the dynamic nature of telomere architecture and the great number of structures that telomeres form. In this Review, we discuss recently determined structures of the shelterin and CTC1-STN1-TEN1 (CST) complexes, how they may participate in the regulation of telomere replication and chromosome end-capping, and how disease-causing mutations in their encoding genes may affect specific functions. Major outstanding questions in the field include how all of the telomere components assemble relative to each other and how the switching between different telomere structures is achieved.
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Affiliation(s)
- Ci Ji Lim
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA. .,Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA. .,BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA.
| | - Thomas R Cech
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA. .,BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA. .,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA.
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23
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Salimi-Jeda A, Badrzadeh F, Esghaei M, Abdoli A. The role of telomerase and viruses interaction in cancer development, and telomerase-dependent therapeutic approaches. Cancer Treat Res Commun 2021; 27:100323. [PMID: 33530025 DOI: 10.1016/j.ctarc.2021.100323] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 12/21/2022]
Abstract
Human telomerase reverse transcriptase (hTERT) is an enzyme that is critically involved in elongating and maintaining telomeres length to control cell life span and replicative potential. Telomerase activity is continuously expressed in human germ-line cells and most cancer cells, whereas it is suppressed in most somatic cells. In normal cells, by reducing telomerase activity and progressively shortening the telomeres, the cells progress to the senescence or apoptosis process. However, in cancer cells, telomere lengths remain constant due to telomerase's reactivation, and cells continue to proliferate and inhibit apoptosis, and ultimately lead to cancer development and human death due to metastasis. Studies demonstrated that several DNA and RNA oncoviruses could interact with telomerase by integrating their genome sequence within the host cell telomeres specifically. Through the activation of the hTERT promoter and lengthening the telomere, these cells contributes to cancer development. Since oncoviruses can activate telomerase and increase hTERT expression, there are several therapeutic strategies based on targeting the telomerase of cancer cells like telomerase-targeted peptide vaccines, hTERT-targeting dendritic cells (DCs), hTERT-targeting gene therapy, and hTERT-targeting CRISPR/Cas9 system that can overcome tumor-mediated toleration mechanisms and specifically apoptosis in cancer cells. This study reviews available data on the molecular structure of telomerase and the role of oncoviruses and telomerase interaction in cancer development and telomerase-dependent therapeutic approaches to conquest the cancer cells.
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Affiliation(s)
- Ali Salimi-Jeda
- Department of Virology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Fariba Badrzadeh
- Faculti of Medicine, Golestan University of Medical sciences, Golestan, Iran.
| | - Maryam Esghaei
- Department of Virology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Asghar Abdoli
- Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran.
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24
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Glousker G, Briod A, Quadroni M, Lingner J. Human shelterin protein POT1 prevents severe telomere instability induced by homology-directed DNA repair. EMBO J 2020; 39:e104500. [PMID: 33073402 PMCID: PMC7705456 DOI: 10.15252/embj.2020104500] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 09/15/2020] [Accepted: 09/18/2020] [Indexed: 01/05/2023] Open
Abstract
The evolutionarily conserved POT1 protein binds single-stranded G-rich telomeric DNA and has been implicated in contributing to telomeric DNA maintenance and the suppression of DNA damage checkpoint signaling. Here, we explore human POT1 function through genetics and proteomics, discovering that a complete absence of POT1 leads to severe telomere maintenance defects that had not been anticipated from previous depletion studies in human cells. Conditional deletion of POT1 in HEK293E cells gives rise to rapid telomere elongation and length heterogeneity, branched telomeric DNA structures, telomeric R-loops, and telomere fragility. We determine the telomeric proteome upon POT1-loss, implementing an improved telomeric chromatin isolation protocol. We identify a large set of proteins involved in nucleic acid metabolism that engage with telomeres upon POT1-loss. Inactivation of the homology-directed repair machinery suppresses POT1-loss-mediated telomeric DNA defects. Our results unravel as major function of human POT1 the suppression of telomere instability induced by homology-directed repair.
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Affiliation(s)
- Galina Glousker
- School of Life SciencesSwiss Institute for Experimental Cancer Research (ISREC)Ecole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - Anna‐Sophia Briod
- School of Life SciencesSwiss Institute for Experimental Cancer Research (ISREC)Ecole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | | | - Joachim Lingner
- School of Life SciencesSwiss Institute for Experimental Cancer Research (ISREC)Ecole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
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25
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Replication stress conferred by POT1 dysfunction promotes telomere relocalization to the nuclear pore. Genes Dev 2020; 34:1619-1636. [PMID: 33122293 PMCID: PMC7706707 DOI: 10.1101/gad.337287.120] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 09/21/2020] [Indexed: 12/31/2022]
Abstract
In this study, Pinzaru et al. set out to uncover the pathways that enable the proliferation of cells expressing cancer-associated POT1 mutations. Using complementary genetic and proteomic approaches, the authors identify a conserved function for the NPC in resolving replication defects at telomere loci. Mutations in the telomere-binding protein POT1 are associated with solid tumors and leukemias. POT1 alterations cause rapid telomere elongation, ATR kinase activation, telomere fragility, and accelerated tumor development. Here, we define the impact of mutant POT1 alleles through complementary genetic and proteomic approaches based on CRISPR interference and biotin-based proximity labeling, respectively. These screens reveal that replication stress is a major vulnerability in cells expressing mutant POT1, which manifests as increased telomere mitotic DNA synthesis at telomeres. Our study also unveils a role for the nuclear pore complex in resolving replication defects at telomeres. Depletion of nuclear pore complex subunits in the context of POT1 dysfunction increases DNA damage signaling, telomere fragility and sister chromatid exchanges. Furthermore, we observed telomere repositioning to the nuclear periphery driven by nuclear F-actin polymerization in cells with POT1 mutations. In conclusion, our study establishes that relocalization of dysfunctional telomeres to the nuclear periphery is critical to preserve telomere repeat integrity.
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26
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Weyburne E, Bosco G. Cancer-associated mutations in the condensin II subunit CAPH2 cause genomic instability through telomere dysfunction and anaphase chromosome bridges. J Cell Physiol 2020; 236:3579-3598. [PMID: 33078399 PMCID: PMC7983937 DOI: 10.1002/jcp.30113] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 01/10/2023]
Abstract
Genome instability in cancer drives tumor heterogeneity, undermines the success of therapies, and leads to metastasis and recurrence. Condensins are conserved chromatin‐binding proteins that promote genomic stability, mainly by ensuring proper condensation of chromatin and mitotic chromosome segregation. Condensin mutations are found in human tumors, but it is not known how or even if such mutations promote cancer progression. In this study, we focus on condensin II subunit CAPH2 and specific CAPH2 mutations reported to be enriched in human cancer patients, and we test how CAPH2 cancer‐specific mutations may lead to condensin II complex dysfunction and contribute to genome instability. We find that R551P, R551S, and S556F mutations in CAPH2 cause genomic instability by causing DNA damage, anaphase defects, micronuclei, and chromosomal instability. DNA damage and anaphase defects are caused primarily by ataxia telangiectasia and Rad3‐related‐dependent telomere dysfunction, as anaphase bridges are enriched for telomeric repeat sequences. We also show that these mutations decrease the binding of CAPH2 to the ATPase subunit SMC4 as well as the rest of the condensin II complex, and decrease the amount of CAPH2 protein bound to chromatin. Thus, in vivo the R551P, R551S, and S556F cancer‐specific CAPH2 mutant proteins are likely to impair condensin II complex formation, impede condensin II activity during mitosis and interphase, and promote genetic heterogeneity in cell populations that can lead to clonal outgrowth of cancer cells with highly diverse genotypes.
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Affiliation(s)
- Emily Weyburne
- Department of Molecular and Systems Biology, Dartmouth College, Hanover, New Hampshire, USA
| | - Giovanni Bosco
- Department of Molecular and Systems Biology, Dartmouth College, Hanover, New Hampshire, USA
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27
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Wu Y, Poulos RC, Reddel RR. Role of POT1 in Human Cancer. Cancers (Basel) 2020; 12:cancers12102739. [PMID: 32987645 PMCID: PMC7598640 DOI: 10.3390/cancers12102739] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 09/20/2020] [Accepted: 09/22/2020] [Indexed: 12/11/2022] Open
Abstract
Simple Summary The segmentation of eukaryotic genomes into discrete linear chromosomes requires processes to solve several major biological problems, including prevention of the chromosome ends being recognized as DNA breaks and compensation for the shortening that occurs when linear DNA is replicated. A specialized set of six proteins, collectively referred to as shelterin, is involved in both of these processes, and mutations in several of these are now known to be involved in cancer. Here, we focus on Protection of Telomeres 1 (POT1), the shelterin protein that appears to be most commonly involved in cancer, and consider the clinical significance of findings about its biological functions and the prevalence of inherited and acquired mutations in the POT1 gene. Abstract Telomere abnormalities facilitate cancer development by contributing to genomic instability and cellular immortalization. The Protection of Telomeres 1 (POT1) protein is an essential subunit of the shelterin telomere binding complex. It directly binds to single-stranded telomeric DNA, protecting chromosomal ends from an inappropriate DNA damage response, and plays a role in telomere length regulation. Alterations of POT1 have been detected in a range of cancers. Here, we review the biological functions of POT1, the prevalence of POT1 germline and somatic mutations across cancer predisposition syndromes and tumor types, and the dysregulation of POT1 expression in cancers. We propose a framework for understanding how POT1 abnormalities may contribute to oncogenesis in different cell types. Finally, we summarize the clinical implications of POT1 alterations in the germline and in cancer, and possible approaches for the development of targeted cancer therapies.
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Affiliation(s)
- Yangxiu Wu
- Cancer Research Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead NSW 2145, Australia;
- ProCan® Cancer Data Science Group, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead NSW 2145, Australia;
| | - Rebecca C. Poulos
- ProCan® Cancer Data Science Group, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead NSW 2145, Australia;
| | - Roger R. Reddel
- Cancer Research Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, The University of Sydney, Westmead NSW 2145, Australia;
- Correspondence: ; Tel.: +61-2-8865-2901
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28
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Boyle JM, Hennick KM, Regalado SG, Vogan JM, Zhang X, Collins K, Hockemeyer D. Telomere length set point regulation in human pluripotent stem cells critically depends on the shelterin protein TPP1. Mol Biol Cell 2020; 31:2583-2596. [PMID: 32903138 PMCID: PMC7851873 DOI: 10.1091/mbc.e19-08-0447] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Telomere maintenance is essential for the long-term proliferation of human pluripotent stem cells, while their telomere length set point determines the proliferative capacity of their differentiated progeny. The shelterin protein TPP1 is required for telomere stability and elongation, but its role in establishing a telomere length set point remains elusive. Here, we characterize the contribution of the shorter isoform of TPP1 (TPP1S) and the amino acid L104 outside the TEL patch, TPP1’s telomerase interaction domain, to telomere length control. We demonstrate that cells deficient for TPP1S (TPP1S knockout [KO]), as well as the complete TPP1 KO cell lines, undergo telomere shortening. However, TPP1S KO cells are able to stabilize short telomeres, while TPP1 KO cells die. We compare these phenotypes with those of TPP1L104A/L104A mutant cells, which have short and stable telomeres similar to the TPP1S KO. In contrast to TPP1S KO cells, TPP1L104A/L104A cells respond to increased telomerase levels and maintain protected telomeres. However, TPP1L104A/L104A shows altered sensitivity to expression changes of shelterin proteins suggesting the mutation causes a defect in telomere length feedback regulation. Together this highlights TPP1L104A/L104A as the first shelterin mutant engineered at the endogenous locus of human stem cells with an altered telomere length set point.
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Affiliation(s)
- John M Boyle
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Kelsey M Hennick
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Samuel G Regalado
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Jacob M Vogan
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Xiaozhu Zhang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Kathleen Collins
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720.,Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720.,Chan Zuckerberg Biohub, San Francisco, CA 94158
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29
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Mudd AB, Bredeson JV, Baum R, Hockemeyer D, Rokhsar DS. Analysis of muntjac deer genome and chromatin architecture reveals rapid karyotype evolution. Commun Biol 2020; 3:480. [PMID: 32873878 PMCID: PMC7463020 DOI: 10.1038/s42003-020-1096-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 05/06/2020] [Indexed: 01/29/2023] Open
Abstract
Closely related muntjac deer show striking karyotype differences. Here we describe chromosome-scale genome assemblies for Chinese and Indian muntjacs, Muntiacus reevesi (2n = 46) and Muntiacus muntjak vaginalis (2n = 6/7), and analyze their evolution and architecture. The genomes show extensive collinearity with each other and with other deer and cattle. We identified numerous fusion events unique to and shared by muntjacs relative to the cervid ancestor, confirming many cytogenetic observations with genome sequence. One of these M. muntjak fusions reversed an earlier fission in the cervid lineage. Comparative Hi-C analysis showed that the chromosome fusions on the M. muntjak lineage altered long-range, three-dimensional chromosome organization relative to M. reevesi in interphase nuclei including A/B compartment structure. This reshaping of multi-megabase contacts occurred without notable change in local chromatin compaction, even near fusion sites. A few genes involved in chromosome maintenance show evidence for rapid evolution, possibly associated with the dramatic changes in karyotype.
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Affiliation(s)
- Austin B Mudd
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Jessen V Bredeson
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Rachel Baum
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Daniel S Rokhsar
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
- Innovative Genomics Institute, University of California, Berkeley, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
- Department of Energy Joint Genome Institute, Walnut Creek, CA, USA.
- Molecular Genetics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan.
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30
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Kafer GR, Cesare AJ. A Survey of Essential Genome Stability Genes Reveals That Replication Stress Mitigation Is Critical for Peri-Implantation Embryogenesis. Front Cell Dev Biol 2020; 8:416. [PMID: 32548123 PMCID: PMC7274024 DOI: 10.3389/fcell.2020.00416] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 05/05/2020] [Indexed: 12/16/2022] Open
Abstract
Murine development demands that pluripotent epiblast stem cells in the peri-implantation embryo increase from approximately 120 to 14,000 cells between embryonic days (E) 4.5 and E7.5. This is possible because epiblast stem cells can complete cell cycles in under 3 h in vivo. To ensure conceptus fitness, epiblast cells must undertake this proliferative feat while maintaining genome integrity. How epiblast cells maintain genome health under such an immense proliferation demand remains unclear. To illuminate the contribution of genome stability pathways to early mammalian development we systematically reviewed knockout mouse data from 347 DDR and repair associated genes. Cumulatively, the data indicate that while many DNA repair functions are dispensable in embryogenesis, genes encoding replication stress response and homology directed repair factors are essential specifically during the peri-implantation stage of early development. We discuss the significance of these findings in the context of the unique proliferative demands placed on pluripotent epiblast stem cells.
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Affiliation(s)
| | - Anthony J. Cesare
- Genome Integrity Unit, Children’s Medical Research Institute, The University of Sydney, Westmead, NSW, Australia
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31
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Hou T, Cao Z, Zhang J, Tang M, Tian Y, Li Y, Lu X, Chen Y, Wang H, Wei FZ, Wang L, Yang Y, Zhao Y, Wang Z, Wang H, Zhu WG. SIRT6 coordinates with CHD4 to promote chromatin relaxation and DNA repair. Nucleic Acids Res 2020; 48:2982-3000. [PMID: 31970415 PMCID: PMC7102973 DOI: 10.1093/nar/gkaa006] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/02/2019] [Accepted: 01/03/2020] [Indexed: 01/08/2023] Open
Abstract
Genomic instability is an underlying hallmark of cancer and is closely associated with defects in DNA damage repair (DDR). Chromatin relaxation is a prerequisite for DDR, but how chromatin accessibility is regulated remains elusive. Here we report that the histone deacetylase SIRT6 coordinates with the chromatin remodeler CHD4 to promote chromatin relaxation in response to DNA damage. Upon DNA damage, SIRT6 rapidly translocates to DNA damage sites, where it interacts with and recruits CHD4. Once at the damage sites, CHD4 displaces heterochromatin protein 1 (HP1) from histone H3 lysine 9 trimethylation (H3K9me3). Notably, loss of SIRT6 or CHD4 leads to impaired chromatin relaxation and disrupted DNA repair protein recruitment. These molecular changes, in-turn, lead to defective homologous recombination (HR) and cancer cell hypersensitivity to DNA damaging agents. Furthermore, we show that SIRT6-mediated CHD4 recruitment has a specific role in DDR within compacted chromatin by HR in G2 phase, which is an ataxia telangiectasia mutated (ATM)-dependent process. Taken together, our results identify a novel function for SIRT6 in recruiting CHD4 onto DNA double-strand breaks. This newly identified novel molecular mechanism involves CHD4-dependent chromatin relaxation and competitive release of HP1 from H3K9me3 within the damaged chromatin, which are both essential for accurate HR.
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Affiliation(s)
- Tianyun Hou
- Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Ziyang Cao
- Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Jun Zhang
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, International Cancer Center, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen 518055, China
| | - Ming Tang
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, International Cancer Center, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen 518055, China
| | - Yuan Tian
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, International Cancer Center, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen 518055, China
| | - Yinglu Li
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, International Cancer Center, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen 518055, China
| | - Xiaopeng Lu
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, International Cancer Center, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen 518055, China
| | - Yongcan Chen
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, International Cancer Center, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen 518055, China
| | - Hui Wang
- Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Fu-Zheng Wei
- Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Lina Wang
- Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yang Yang
- Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Ying Zhao
- Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Zimei Wang
- Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, International Cancer Center, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen 518055, China
| | - Haiying Wang
- Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Wei-Guo Zhu
- Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China.,Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, International Cancer Center, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen 518055, China
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32
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Fernandes CAH, Morea EGO, Dos Santos GA, da Silva VL, Vieira MR, Viviescas MA, Chatain J, Vadel A, Saintomé C, Fontes MRM, Cano MIN. A multi-approach analysis highlights the relevance of RPA-1 as a telomere end-binding protein (TEBP) in Leishmania amazonensis. Biochim Biophys Acta Gen Subj 2020; 1864:129607. [PMID: 32222548 DOI: 10.1016/j.bbagen.2020.129607] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/21/2020] [Accepted: 03/24/2020] [Indexed: 01/12/2023]
Abstract
BACKGROUND Telomeres are chromosome end structures important in the maintenance of genome homeostasis. They are replenished by the action of telomerase and associated proteins, such as the OB (oligonucleotide/oligosaccharide-binding)-fold containing telomere-end binding proteins (TEBP) which plays an essential role in telomere maintenance and protection. The nature of TEBPs is well known in higher and some primitive eukaryotes, but it remains undetermined in trypanosomatids. Previous in silico searches have shown that there are no homologs of the classical TEPBs in trypanosomatids, including Leishmania sp. However, Replication Protein A subunit 1 (RPA-1), an OB-fold containing DNA-binding protein, was found co-localized with trypanosomatids telomeres and showed a high preference for the telomeric G-rich strand. METHODS AND RESULTS We predicted the absence of structural homologs of OB-fold containing TEBPs in the Leishmania sp. genome using structural comparisons. We demonstrated by molecular docking that the ssDNA binding mode of LaRPA-1 shares features with the higher eukaryotes POT1 and RPA-1 crystal structures ssDNA binding mode. Using fluorescence spectroscopy, protein-DNA interaction assays, and FRET, we respectively show that LaRPA-1 shares some telomeric functions with the classical TEBPs since it can bind at least one telomeric repeat, protect the telomeric G-rich DNA from 3'-5' Exonuclease I digestion, and unfold telomeric G-quadruplex. CONCLUSIONS Our results suggest that RPA-1 emerges as a TEBP in trypanosomatids, and in this context, we present two possible evolutionary landscapes of trypanosomatids RPA-1 that could reflect upon the evolution of OB-fold containing TEBPs from all eukaryotes.
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Affiliation(s)
- Carlos A H Fernandes
- Department of Biophysics and Pharmacology, Biosciences Institute, São Paulo State University (UNESP) - Botucatu, SP, Brazil; Laboratoire de Biologie et Pharmacologie Appliquée, École Normale Supérieure Paris-Saclay, Cachan, France
| | - Edna Gicela O Morea
- Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil
| | - Gabriel A Dos Santos
- Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil
| | - Vitor L da Silva
- Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil
| | - Marina Roveri Vieira
- Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil
| | - Maria Alejandra Viviescas
- Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil
| | - Jean Chatain
- MNHN CNRS UMR 7196, INSERM U1154, 43 rue Cuvier, 75005 Paris, France
| | - Aurélie Vadel
- MNHN CNRS UMR 7196, INSERM U1154, 43 rue Cuvier, 75005 Paris, France
| | - Carole Saintomé
- MNHN CNRS UMR 7196, INSERM U1154, 43 rue Cuvier, 75005 Paris, France; Sorbonne Université, UFR927, 4 place Jussieu, 75005 Paris, France
| | - Marcos Roberto M Fontes
- Department of Biophysics and Pharmacology, Biosciences Institute, São Paulo State University (UNESP) - Botucatu, SP, Brazil
| | - Maria Isabel Nogueira Cano
- Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil.
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33
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Gong Y, Stock AJ, Liu Y. The enigma of excessively long telomeres in cancer: lessons learned from rare human POT1 variants. Curr Opin Genet Dev 2020; 60:48-55. [PMID: 32155570 DOI: 10.1016/j.gde.2020.02.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/17/2020] [Accepted: 02/02/2020] [Indexed: 01/10/2023]
Abstract
The discovery that rare POT1 variants are associated with extremely long telomeres and increased cancer predisposition has provided a framework to revisit the relationship between telomere length and cancer development. Telomere shortening is linked with increased risk for cancer. However, over the past decade, there is increasing evidence to show that extremely long telomeres caused by mutations in shelterin components (POT1, TPP1, and RAP1) also display an increased risk of cancer. Here, we will review current knowledge on germline mutations of POT1 identified from cancer-prone families. In particular, we will discuss some common features presented by the mutations through structure-function studies. We will further provide an overview of how POT1 mutations affect telomere length regulation and tumorigenesis.
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Affiliation(s)
- Yi Gong
- Biomedical Research Center, National Institute on Aging/National Institutes of Health, 251 Bayview Blvd, Baltimore, MD, USA.
| | - Amanda J Stock
- Biomedical Research Center, National Institute on Aging/National Institutes of Health, 251 Bayview Blvd, Baltimore, MD, USA
| | - Yie Liu
- Biomedical Research Center, National Institute on Aging/National Institutes of Health, 251 Bayview Blvd, Baltimore, MD, USA.
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34
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Martínez-Cué C, Rueda N. Cellular Senescence in Neurodegenerative Diseases. Front Cell Neurosci 2020; 14:16. [PMID: 32116562 PMCID: PMC7026683 DOI: 10.3389/fncel.2020.00016] [Citation(s) in RCA: 185] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/21/2020] [Indexed: 01/10/2023] Open
Abstract
Cellular senescence is a homeostatic biological process characterized by a permanent state of cell cycle arrest that can contribute to the decline of the regenerative potential and function of tissues. The increased presence of senescent cells in different neurodegenerative diseases suggests the contribution of senescence in the pathophysiology of these disorders. Although several factors can induce senescence, DNA damage, oxidative stress, neuroinflammation, and altered proteostasis have been shown to play a role in its onset. Oxidative stress contributes to accelerated aging and cognitive dysfunction stages affecting neurogenesis, neuronal differentiation, connectivity, and survival. During later life stages, it is implicated in the progression of cognitive decline, synapse loss, and neuronal degeneration. Also, neuroinflammation exacerbates oxidative stress, synaptic dysfunction, and neuronal death through the harmful effects of pro-inflammatory cytokines on cell proliferation and maturation. Both oxidative stress and neuroinflammation can induce DNA damage and alterations in DNA repair that, in turn, can exacerbate them. Another important feature associated with senescence is altered proteostasis. Because of the disruption in the function and balance of the proteome, senescence can modify the proper synthesis, folding, quality control, and degradation rate of proteins producing, in some diseases, misfolded proteins or aggregation of abnormal proteins. There is an extensive body of literature that associates cellular senescence with several neurodegenerative disorders including Alzheimer’s disease (AD), Down syndrome (DS), and Parkinson’s disease (PD). This review summarizes the evidence of the shared neuropathological events in these neurodegenerative diseases and the implication of cellular senescence in their onset or aggravation. Understanding the role that cellular senescence plays in them could help to develop new therapeutic strategies.
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Affiliation(s)
- Carmen Martínez-Cué
- Department of Physiology and Pharmacology, Faculty of Medicine, University of Cantabria, Santander, Spain
| | - Noemí Rueda
- Department of Physiology and Pharmacology, Faculty of Medicine, University of Cantabria, Santander, Spain
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35
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Shen E, Xiu J, Lopez GY, Bentley R, Jalali A, Heimberger AB, Bainbridge MN, Bondy ML, Walsh KM. POT1 mutation spectrum in tumour types commonly diagnosed among POT1-associated hereditary cancer syndrome families. J Med Genet 2020; 57:664-670. [PMID: 31937561 DOI: 10.1136/jmedgenet-2019-106657] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/20/2019] [Accepted: 12/21/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND The shelterin complex is composed of six proteins that protect and regulate telomere length, including protection of telomeres 1 (POT1). Germline POT1 mutations are associated with an autosomal dominant familial cancer syndrome presenting with diverse malignancies, including glioma, angiosarcoma, colorectal cancer and melanoma. Although somatic POT1 mutations promote telomere elongation and genome instability in chronic lymphocytic leukaemia, the contribution of POT1 mutations to development of other sporadic cancers is largely unexplored. METHODS We performed logistic regression, adjusted for tumour mutational burden, to identify associations between POT1 mutation frequency and tumour type in 62 368 tumours undergoing next-generation sequencing. RESULTS A total of 1834 tumours harboured a non-benign mutation of POT1 (2.94%), of which 128 harboured a mutation previously reported to confer familial cancer risk in the setting of germline POT1 deficiency. Angiosarcoma was 11 times more likely than other tumours to harbour a POT1 mutation (p=1.4×10-20), and 65% of POT1-mutated angiosarcoma had >1 mutations in POT1. Malignant gliomas were 1.7 times less likely to harbour a POT1 mutation (p=1.2×10-3) than other tumour types. Colorectal cancer was 1.2 times less likely to harbour a POT1 mutation (p=0.012), while melanoma showed no differences in POT1 mutation frequency versus other tumours (p=0.67). CONCLUSIONS These results confirm a role for shelterin dysfunction in angiosarcoma development but suggest that gliomas arising in the context of germline POT1 deficiency activate a telomere-lengthening mechanism that is uncommon in gliomagenesis.
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Affiliation(s)
- Erica Shen
- Department of Neurosurgery, Duke University School of Medicine, Durham, North Carolina, USA
| | - Joanne Xiu
- Medical Affairs, Caris Life Sciences Inc, Phoenix, Arizona, USA
| | - Giselle Y Lopez
- Department of Pathology, Duke University School of Medicine, Durham, North Carolina, USA.,Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Rex Bentley
- Department of Pathology, Duke University School of Medicine, Durham, North Carolina, USA.,Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Ali Jalali
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas, USA
| | - Amy B Heimberger
- Department of Neurosurgery, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | | | - Melissa L Bondy
- Epidemiology and Population Health, Stanford University School of Medicine, Palo Alto, California, USA
| | - Kyle M Walsh
- Department of Neurosurgery, Duke University School of Medicine, Durham, North Carolina, USA .,Department of Pathology, Duke University School of Medicine, Durham, North Carolina, USA.,Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina, USA
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Amir M, Ahamad S, Mohammad T, Jairajpuri DS, Hasan GM, Dohare R, Islam A, Ahmad F, Hassan MI. Investigation of conformational dynamics of Tyr89Cys mutation in protection of telomeres 1 gene associated with familial melanoma. J Biomol Struct Dyn 2019; 39:35-44. [DOI: 10.1080/07391102.2019.1705186] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Mohd. Amir
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Shahzaib Ahamad
- Department of Biotechnology, School of Engineering & Technology, IFTM University, Moradabad, India
| | - Taj Mohammad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Deeba Shamim Jairajpuri
- Department of Medical Biochemistry, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain
| | - Gulam Mustafa Hasan
- Department of Biochemistry, College of Medicine, Prince Sattam Bin Abdulaziz University, Al-Kharj, Kingdom of Saudi Arabia
| | - Ravins Dohare
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Faizan Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
| | - Md. Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
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Jacobs DI, Fukumura K, Bainbridge MN, Armstrong GN, Tsavachidis S, Gu X, Doddapaneni HV, Hu J, Jayaseelan JC, Muzny DM, Huse JT, Bondy ML. Elucidating the molecular pathogenesis of glioma: integrated germline and somatic profiling of a familial glioma case series. Neuro Oncol 2019; 20:1625-1633. [PMID: 30165405 DOI: 10.1093/neuonc/noy119] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Background The genomic characterization of sporadically arising gliomas has delineated molecularly and clinically distinct subclasses of disease. However, less is known about the molecular nature of gliomas that are familial in origin. We performed molecular subtyping of 163 tumor specimens from individuals with a family history of glioma and integrated germline and somatic genomic data to characterize the pathogenesis of 20 tumors in additional detail. Methods Immunohistochemical analyses were performed on formalin-fixed, paraffin-embedded tumor sections to determine molecular subtypes of glioma. For 20 cases, tumor DNA was exome sequenced on an Illumina HiSeq 2000 platform and copy number profiling was performed on the Illumina HumanOmniExpress BeadChip. Genotypes at glioma risk polymorphisms were determined from germline DNA profiled on the Illumina Infinium OncoArray and deleterious germline mutations were identified from germline sequencing data. Results All 3 molecular subtypes of sporadic glioma were represented in the overall case series, including molecular glioblastoma (n = 102), oligodendroglioma (n = 21), and astrocytoma (n = 20). Detailed profiling of 20 of these cases showed characteristic subtype-specific alterations at frequencies comparable to sporadic glioma cases. All 20 cases had alterations in genes regulating telomere length. Frequencies of common glioma risk alleles were similar to those among sporadic cases, and correlations between risk alleles and same-gene somatic mutations were not observed. Conclusions This study illustrates that the molecular characteristics of familial tumors profiled largely recapitulate what is known about sporadic glioma and that both germline and somatic molecular features target common core pathways involved in gliomagenesis. Key Points 1. Familial and sporadic gliomas display highly comparable molecular landscapes. 2. Germline and somatic molecular events target common core pathways involved in gliomagenesis. 3. Carriage of germline glioma risk variants is not associated with somatic events in the same gene.
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Affiliation(s)
- Daniel I Jacobs
- Department of Medicine, Section of Epidemiology and Population Sciences, Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas
| | - Kazutaka Fukumura
- Departments of Pathology and Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Matthew N Bainbridge
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Institute for Genomic Medicine, Rady Children's Hospital, San Diego, California
| | - Georgina N Armstrong
- Department of Medicine, Section of Epidemiology and Population Sciences, Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas
| | - Spiridon Tsavachidis
- Department of Medicine, Section of Epidemiology and Population Sciences, Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas
| | - Xiangjun Gu
- Department of Medicine, Section of Epidemiology and Population Sciences, Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas
| | - Harsha V Doddapaneni
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Jianhong Hu
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Joy C Jayaseelan
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Donna M Muzny
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Jason T Huse
- Departments of Pathology and Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Melissa L Bondy
- Department of Medicine, Section of Epidemiology and Population Sciences, Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas
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38
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Kobayashi CR, Castillo-González C, Survotseva Y, Canal E, Nelson ADL, Shippen DE. Recent emergence and extinction of the protection of telomeres 1c gene in Arabidopsis thaliana. PLANT CELL REPORTS 2019; 38:1081-1097. [PMID: 31134349 PMCID: PMC6708462 DOI: 10.1007/s00299-019-02427-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/27/2019] [Indexed: 05/20/2023]
Abstract
Duplicate POT1 genes must rapidly diverge or be inactivated. Protection of telomeres 1 (POT1) encodes a conserved telomere binding protein implicated in both chromosome end protection and telomere length maintenance. Most organisms harbor a single POT1 gene, but in the few lineages where the POT1 family has expanded, the duplicate genes have diversified. Arabidopsis thaliana bears three POT1-like loci, POT1a, POT1b and POT1c. POT1a retains the ancestral function of telomerase regulation, while POT1b is implicated in chromosome end protection. Here we examine the function and evolution of the third POT1 paralog, POT1c. POT1c is a new gene, unique to A. thaliana, and was derived from a duplication event involving the POT1a locus and a neighboring gene encoding ribosomal protein S17. The duplicate S17 locus (dS17) is highly conserved across A. thaliana accessions, while POT1c is highly divergent, harboring multiple deletions within the gene body and two transposable elements within the promoter. The POT1c locus is transcribed at very low to non-detectable levels under standard growth conditions. In addition, no discernable molecular or developmental defects are associated with plants bearing a CRISPR mutation in the POT1c locus. However, forced expression of POT1c leads to decreased telomerase enzyme activity and shortened telomeres. Evolutionary reconstruction indicates that transposons invaded the POT1c promoter soon after the locus was formed, permanently silencing the gene. Altogether, these findings argue that POT1 dosage is critically important for viability and duplicate gene copies are retained only upon functional divergence.
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Affiliation(s)
- Callie R Kobayashi
- Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | | | - Yulia Survotseva
- Yale Center for Molecular Discovery, Yale University, New Haven, Connecticut, USA
| | - Elijah Canal
- Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Andrew D L Nelson
- The School of Plant Sciences, University of Arizona, Tucson, Arizona, USA
| | - Dorothy E Shippen
- Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA.
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Zalzman M, Meltzer WA, Portney BA, Brown RA, Gupta A. The Role of Ubiquitination and SUMOylation in Telomere Biology. Curr Issues Mol Biol 2019; 35:85-98. [PMID: 31422934 DOI: 10.21775/cimb.035.085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Telomeres are a unique structure of DNA repeats covered by proteins at the ends of the chromosomes that protect the coding regions of the genome and function as a biological clock. They require a tight regulation of the factors covering and protecting their structure, as they are shortened with each cell division to limit the ability of cells to replicate uncontrollably. Additionally, they protect the chromosome ends from DNA damage responses and thereby, prevent genomic instability. Telomere dysfunction can lead to chromosomal abnormalities and cancer. Therefore, dysregulation of any of the factors that regulate the integrity of the telomeres will have implications to chromosomal stability, replicative lifespan and may lead to cell transformation. This review will cover the main factors participating in the normal function of the telomeres and how these are regulated by the ubiquitin and SUMO systems. Accumulating evidence indicate that the ubiquitin and SUMO pathways are significant regulators of the shelterin complex and other chromatin modifiers, which are important for telomere structure integrity. Furthermore, the crosstalk between these two pathways has been reported in telomeric DNA repair. A better understanding of the factors contributing to telomere biology, and how they are regulated, is important for the design of new strategies for cancer therapies and regenerative medicine.
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Affiliation(s)
- Michal Zalzman
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - W Alex Meltzer
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Benjamin A Portney
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Robert A Brown
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Aditi Gupta
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
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40
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Wang J, Wang C, Yu HB, Dela Ahator S, Wu X, Lv S, Zhang LH. Bacterial quorum-sensing signal IQS induces host cell apoptosis by targeting POT1-p53 signalling pathway. Cell Microbiol 2019; 21:e13076. [PMID: 31254473 DOI: 10.1111/cmi.13076] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/05/2019] [Accepted: 06/20/2019] [Indexed: 01/01/2023]
Abstract
Pseudomonas aeruginosa, an opportunistic life-threatening human bacterial pathogen, employs quorum-sensing (QS) signal molecules to modulate virulence gene expression. 2-(2-hydroxyphenyl)-thiazole-4-carbaldehyde (IQS) is a recently identified QS signal that integrates the canonical lasR-type QS of P. aeruginosa and host phosphate stress response to fine-tune its virulence production for a successful infection. To address the role of IQS in pathogen-host interaction, we here present that IQS inhibits host cell growth and stimulates apoptosis in a dosage-dependent manner. By downregulating the telomere-protecting protein POT1 in host cells, IQS activates CHK1, CHK2, and p53 in an Ataxia telangiectasia mutated (ATM)/ATM and RAD3-related (ATR)-dependent manner and induces DNA damage response. Overexpression of POT1 in host cells presents a resistance to IQS treatment. These results suggest a pivotal role of IQS in host apoptosis, highlighting the complexity of pathogenesis mechanisms developed by P. aeruginosa during infection.
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Affiliation(s)
- Jianhe Wang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Institute of Molecular and Cell Biology, Singapore
| | - Chao Wang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Division of Cellular and Molecular Research, National Cancer Center Singapore, Singapore
| | - Hong-Bing Yu
- Dongguan Scientific Research Center, Guangdong Medical University, Dongguan, 523808, Guangdong province, China.,Scientific Research Platform of the second school of clinical medicine, Guangdong Medical University, Dongguan, 523808, Guangdong province, China
| | - Stephen Dela Ahator
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Xiaoyan Wu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Shumei Lv
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Lian-Hui Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Institute of Molecular and Cell Biology, Singapore
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41
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Klebanov-Akopyan O, Mishra A, Glousker G, Tzfati Y, Shlomai J. Trypanosoma brucei UMSBP2 is a single-stranded telomeric DNA binding protein essential for chromosome end protection. Nucleic Acids Res 2019; 46:7757-7771. [PMID: 30007364 PMCID: PMC6125633 DOI: 10.1093/nar/gky597] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 07/06/2018] [Indexed: 01/22/2023] Open
Abstract
Universal minicircle sequence binding proteins (UMSBPs) are CCHC-type zinc-finger proteins that bind a single-stranded G-rich sequence, UMS, conserved at the replication origins of the mitochondrial (kinetoplast) DNA of trypanosomatids. Here, we report that Trypanosoma brucei TbUMSBP2, which has been previously proposed to function in the replication and segregation of the mitochondrial DNA, colocalizes with telomeres at the nucleus and is essential for their structure, protection and function. Knockdown of TbUMSBP2 resulted in telomere clustering in one or few foci, phosphorylation of histone H2A at the vicinity of the telomeres, impaired nuclear division, endoreduplication and cell growth arrest. Furthermore, TbUMSBP2 depletion caused rapid reduction in the G-rich telomeric overhang, and an increase in C-rich single-stranded telomeric DNA and in extrachromosomal telomeric circles. These results indicate that TbUMSBP2 is essential for the integrity and function of telomeres. The sequence similarity between the mitochondrial UMS and the telomeric overhang and the finding that UMSBPs bind both sequences suggest a common origin and/or function of these interactions in the replication and maintenance of the genomes in the two organelles. This feature could have converged or preserved during the evolution of the nuclear and mitochondrial genomes from their ancestral (likely circular) genome in early diverged protists.
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Affiliation(s)
- Olga Klebanov-Akopyan
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada and Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Amartya Mishra
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada and Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Galina Glousker
- Department of Genetics, The Silberman Institute of Life Sciences, Edmond Safra Campus, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Sciences, Edmond Safra Campus, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Joseph Shlomai
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada and Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
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42
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Konieczna N, Romaniuk-Drapała A, Lisiak N, Totoń E, Paszel-Jaworska A, Kaczmarek M, Rubiś B. Telomerase Inhibitor TMPyP4 Alters Adhesion and Migration of Breast-Cancer Cells MCF7 and MDA-MB-231. Int J Mol Sci 2019; 20:ijms20112670. [PMID: 31151281 PMCID: PMC6600420 DOI: 10.3390/ijms20112670] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/24/2019] [Accepted: 05/28/2019] [Indexed: 12/26/2022] Open
Abstract
Human telomeres were one of the first discovered and characterized sequences forming quadruplex structures. Association of these structures with oncogenic and tumor suppressor proteins suggests their important role in cancer development and therapy efficacy. Since cationic porphyrin TMPyP4 is known as G-quadruplex stabilizer and telomerase inhibitor, the aim of the study was to analyze the anticancer properties of this compound in two different human breast-cancer MCF7 and MDA-MB-231 cell lines. The cytotoxicity of TMPyP4 alone or in combination with doxorubicin was measured by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromid) and clonogenic assays, and the cell-cycle alterations were analyzed by flow cytometry. Telomerase expression and activity were evaluated using qPCR and telomeric repeat amplification protocol (TRAP) assays, respectively. The contribution of G-quadruplex inhibitor to protein pathways engaged in cell survival, DNA repair, adhesion, and migration was performed using immunodetection. Scratch assay and functional assessment of migration and cell adhesion were also performed. Consequently, it was revealed that in the short term, TMPyP4 neither revealed cytotoxic effect nor sensitized MCF7 and MDA-MB-231 to doxorubicin, but altered breast-cancer cell adhesion and migration. It suggests that TMPyP4 might substantially contribute to a significant decrease in cancer cell dissemination and, consequently, cancer cell survival reduction. Importantly, this effect might not be associated with telomeres or telomerase.
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Affiliation(s)
- Natalia Konieczna
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland.
- Department of Medical Diagnostics, 38A Dobra St., 60-595 Poznań, Poland.
| | - Aleksandra Romaniuk-Drapała
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland.
| | - Natalia Lisiak
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland.
| | - Ewa Totoń
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland.
| | - Anna Paszel-Jaworska
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland.
| | - Mariusz Kaczmarek
- Department of Immunology, Chair of Clinical Immunology, Poznan University of Medical Sciences, 5D Rokietnicka St., 60-806 Poznań, Poland.
| | - Błażej Rubiś
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland.
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Amir M, Ahmad S, Ahamad S, Kumar V, Mohammad T, Dohare R, Alajmi MF, Rehman T, Hussain A, Islam A, Ahmad F, Hassan MI. Impact of Gln94Glu mutation on the structure and function of protection of telomere 1, a cause of cutaneous familial melanoma. J Biomol Struct Dyn 2019; 38:1514-1524. [DOI: 10.1080/07391102.2019.1610500] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Mohd. Amir
- Jamia Millia Islamia, Jamia Nagar, Centre for Interdisciplinary Research in Basic Sciences, New Delhi, India
| | - Shahnawaz Ahmad
- Department of Biotechnology, School of Engineering &Technology, IFTM University, Lodhipur-Rajput, Moradabad, Uttar Pradesh, India
| | - Shahzaib Ahamad
- Department of Biotechnology, School of Engineering &Technology, IFTM University, Lodhipur-Rajput, Moradabad, Uttar Pradesh, India
| | - Vijay Kumar
- Amity Institute of Neuropsychology & Neurosciences, Amity University, Noida, Uttar Pradesh, India
| | - Taj Mohammad
- Jamia Millia Islamia, Jamia Nagar, Centre for Interdisciplinary Research in Basic Sciences, New Delhi, India
| | - Ravins Dohare
- Jamia Millia Islamia, Jamia Nagar, Centre for Interdisciplinary Research in Basic Sciences, New Delhi, India
| | - Mohamed F. Alajmi
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, KSA
| | - Tabish Rehman
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, KSA
| | - Afzal Hussain
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, KSA
| | - Asimul Islam
- Jamia Millia Islamia, Jamia Nagar, Centre for Interdisciplinary Research in Basic Sciences, New Delhi, India
| | - Faizan Ahmad
- Jamia Millia Islamia, Jamia Nagar, Centre for Interdisciplinary Research in Basic Sciences, New Delhi, India
| | - Md. Imtaiyaz Hassan
- Jamia Millia Islamia, Jamia Nagar, Centre for Interdisciplinary Research in Basic Sciences, New Delhi, India
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44
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Doksani Y. The Response to DNA Damage at Telomeric Repeats and Its Consequences for Telomere Function. Genes (Basel) 2019; 10:genes10040318. [PMID: 31022960 PMCID: PMC6523756 DOI: 10.3390/genes10040318] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/13/2019] [Accepted: 04/18/2019] [Indexed: 01/17/2023] Open
Abstract
Telomeric repeats, coated by the shelterin complex, prevent inappropriate activation of the DNA damage response at the ends of linear chromosomes. Shelterin has evolved distinct solutions to protect telomeres from different aspects of the DNA damage response. These solutions include formation of t-loops, which can sequester the chromosome terminus from DNA-end sensors and inhibition of key steps in the DNA damage response. While blocking the DNA damage response at chromosome ends, telomeres make wide use of many of its players to deal with exogenous damage and replication stress. This review focuses on the interplay between the end-protection functions and the response to DNA damage occurring inside the telomeric repeats, as well as on the consequences that telomere damage has on telomere structure and function.
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Affiliation(s)
- Ylli Doksani
- IFOM, The FIRC Institute of Molecular Oncology, via Adamello 16, 20139 Milan, Italy.
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45
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Shoeb M, Mustafa GM, Joseph P, Umbright C, Kodali V, Roach KA, Meighan T, Roberts JR, Erdely A, Antonini JM. Initiation of Pulmonary Fibrosis after Silica Inhalation in Rats is linked with Dysfunctional Shelterin Complex and DNA Damage Response. Sci Rep 2019; 9:471. [PMID: 30679488 PMCID: PMC6346028 DOI: 10.1038/s41598-018-36712-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 11/19/2018] [Indexed: 12/16/2022] Open
Abstract
Occupational exposure to silica has been observed to cause pulmonary fibrosis and lung cancer through complex mechanisms. Telomeres, the nucleoprotein structures with repetitive (TTAGGG) sequences at the end of chromosomes, are a molecular "clock of life", and alterations are associated with chronic disease. The shelterin complex (POT1, TRF1, TRF2, Tin2, Rap1, and POT1 and TPP1) plays an important role in maintaining telomere length and integrity, and any alteration in telomeres may activate DNA damage response (DDR) machinery resulting in telomere attrition. The goal of this study was to assess the effect of silica exposure on the regulation of the shelterin complex in an animal model. Male Fisher 344 rats were exposed by inhalation to Min-U-Sil 5 silica for 3, 6, or 12 wk at a concentration of 15 mg/m3 for 6 hr/d for 5 consecutive d/wk. Expression of shelterin complex genes was assessed in the lungs at 16 hr after the end of each exposure. Also, the relationship between increased DNA damage protein (γH2AX) and expression of silica-induced fibrotic marker, αSMA, was evaluated. Our findings reveal new information about the dysregulation of shelterin complex after silica inhalation in rats, and how this pathway may lead to the initiation of silica-induced pulmonary fibrosis.
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Affiliation(s)
- Mohammad Shoeb
- Centers for Disease Control and Prevention, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA.
| | - Gul M Mustafa
- Centers for Disease Control and Prevention, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
| | - Pius Joseph
- Centers for Disease Control and Prevention, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
| | - Christina Umbright
- Centers for Disease Control and Prevention, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
| | - Vamsi Kodali
- Centers for Disease Control and Prevention, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
| | - Katherine A Roach
- Centers for Disease Control and Prevention, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
| | - Terence Meighan
- Centers for Disease Control and Prevention, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
| | - Jenny R Roberts
- Centers for Disease Control and Prevention, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
| | - Aaron Erdely
- Centers for Disease Control and Prevention, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
| | - James M Antonini
- Centers for Disease Control and Prevention, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, 26505, USA
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46
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Amir M, Kumar V, Mohammad T, Dohare R, Hussain A, Rehman MT, Alam P, Alajmi MF, Islam A, Ahmad F, Hassan MI. Investigation of deleterious effects of nsSNPs in the
POT1
gene: a structural genomics‐based approach to understand the mechanism of cancer development. J Cell Biochem 2018; 120:10281-10294. [DOI: 10.1002/jcb.28312] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 11/28/2018] [Indexed: 12/18/2022]
Affiliation(s)
- Mohd. Amir
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia New Delhi India
| | - Vijay Kumar
- Amity Institute of Neuropsychology & Neurosciences, Amity University Noida Uttar Pradesh India
| | - Taj Mohammad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia New Delhi India
| | - Ravins Dohare
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia New Delhi India
| | - Afzal Hussain
- Department of Pharmacognosy College of Pharmacy, King Saud University Riyadh Saudi Arabia
| | - Md. Tabish Rehman
- Department of Pharmacognosy College of Pharmacy, King Saud University Riyadh Saudi Arabia
| | - Perwez Alam
- Department of Pharmacognosy College of Pharmacy, King Saud University Riyadh Saudi Arabia
| | - Mohamed F. Alajmi
- Department of Pharmacognosy College of Pharmacy, King Saud University Riyadh Saudi Arabia
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia New Delhi India
| | - Faizan Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia New Delhi India
| | - Md. Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia New Delhi India
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47
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Kratz K, de Lange T. Protection of telomeres 1 proteins POT1a and POT1b can repress ATR signaling by RPA exclusion, but binding to CST limits ATR repression by POT1b. J Biol Chem 2018; 293:14384-14392. [PMID: 30082315 DOI: 10.1074/jbc.ra118.004598] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 08/02/2018] [Indexed: 12/15/2022] Open
Abstract
Comprised of telomeric TTAGGG repeats and shelterin, telomeres ensure that the natural ends of chromosomes remain impervious to the DNA damage response. Telomeres carry a long constitutive 3' overhang that can bind replication protein A (RPA) and activate the ATR Ser/Thr kinase (ATR), which induces cell cycle arrest. A single-stranded (ss) TTAGGG repeat-binding protein in mouse shelterin, POT1a, has been proposed to repress ATR signaling by preventing RPA binding. Repression of ATR at telomeres requires tethering of POT1a to the other shelterin subunits situated on the double-stranded (ds) telomeric DNA. The simplest model of ATR repression, the "tethered exclusion model," suggests that the only critical features of POT1a are its connection to shelterin and its binding to ss telomeric DNA. In agreement with the model, we show here that a shelterin-tethered variant of RPA70 (lacking the ATR recruitment domain) can repress ATR signaling at telomeres that lack POT1a. However, arguing against the tethered exclusion model, the nearly identical POT1b subunit of shelterin has been shown to be much less proficient than POT1a in repression of ATR. We now show that POT1b has the intrinsic ability to fully repress ATR but is prevented from doing so when bound to Ctc1, Stn1, Ten1 (CST), the complex needed for telomere end processing. These results establish that shelterin represses ATR with a tethered ssDNA-binding domain that excludes RPA from the 3' overhang and also reveal an unexpected effect of CST on the ability of POT1b to repress ATR.
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Affiliation(s)
- Katja Kratz
- From the Laboratory for Cell Biology and Genetics, Rockefeller University, New York, New York 10021
| | - Titia de Lange
- From the Laboratory for Cell Biology and Genetics, Rockefeller University, New York, New York 10021
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48
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Curigliano G. Targeting DNA Repair. Handb Exp Pharmacol 2018; 249:161-180. [PMID: 30341723 DOI: 10.1007/164_2017_31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Genomic instability is a characteristic of most human cancers and plays critical roles in both cancer development and progression. There are various forms of genomic instability arising from many different pathways, such as DNA damage from endogenous and exogenous sources, centrosome amplification, telomere damage, and epigenetic modifications. DNA-repair pathways can enable tumor cells to survive DNA damage. The failure to respond to DNA damage is a characteristic associated with genomic instability. Understanding of genomic instability in cancer is still very limited, but the further understanding of the molecular mechanisms through which the DNA damage response (DDR) operates, in combination with the elucidation of the genetic interactions between DDR pathways and other cell pathways, will provide therapeutic opportunities for the personalized medicine of cancer.
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Affiliation(s)
- Giuseppe Curigliano
- Early Drug Development for Innovative Therapy Division, European Institute of Oncology, Via Ripamonti, 435 20141, Milan, Italy.
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49
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Zhou G, Liu X, Li Y, Xu S, Ma C, Wu X, Cheng Y, Yu Z, Zhao G, Chen Y. Telomere targeting with a novel G-quadruplex-interactive ligand BRACO-19 induces T-loop disassembly and telomerase displacement in human glioblastoma cells. Oncotarget 2017; 7:14925-39. [PMID: 26908447 PMCID: PMC4924762 DOI: 10.18632/oncotarget.7483] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 01/29/2016] [Indexed: 12/12/2022] Open
Abstract
Interference with telomerase and telomere maintenance is emerging as an attractive target for anticancer therapies. Ligand-induced stabilization of G-quadruplex formation by the telomeric DNA 3'-overhang inhibits telomerase from catalyzing telomeric DNA synthesis and from capping telomeric ends, making these ligands good candidates for chemotherapeutic purposes. BRACO-19 is one of the most effective and specific ligand for telomeric G4. It is shown here that BRACO-19 suppresses proliferation and reduces telomerase activity in human glioblastoma cells, paralleled by the displacement of telomerase from nuclear to cytoplasm. Meanwhile, BRACO-19 triggers extensive DNA damage response at telomere, which may result from uncapping and disassembly of telomeric T-loop structure, characterized by the formation of anaphase bridge and telomere fusion, as well as the release of telomere-binding protein from telomere. The resulting dysfunctional telomere ultimately provokes p53 and p21-mediated cell cycle arrest, apoptosis and senescence. Notably, normal primary astrocytes do not respond to the treatment of BRACO-19, suggesting the agent's good selectivity for cancer cells. These results reinforce the notion that G-quadruplex binding compounds can act as broad inhibitors of telomere-related processes and have potential as selective antineoplastic drugs for various tumors including malignant gliomas.
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Affiliation(s)
- Guangtong Zhou
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, China
| | - Xinrui Liu
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, China
| | - Yunqian Li
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, China
| | - Songbai Xu
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, China
| | - Chengyuan Ma
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, China
| | - Xinmin Wu
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, China
| | - Ye Cheng
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, China
| | - Zhiyun Yu
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, China
| | - Gang Zhao
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, China
| | - Yong Chen
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, China
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50
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Yu Y, Tan R, Ren Q, Gao B, Sheng Z, Zhang J, Zheng X, Jiang Y, Lan L, Mao Z. POT1 inhibits the efficiency but promotes the fidelity of nonhomologous end joining at non-telomeric DNA regions. Aging (Albany NY) 2017; 9:2529-2543. [PMID: 29227966 PMCID: PMC5764391 DOI: 10.18632/aging.101339] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 12/01/2017] [Indexed: 11/25/2022]
Abstract
Robust DNA double strand break (DSB) repair and stabilized telomeres help maintain genome integrity, preventing the onset of aging or tumorigenesis. POT1 is one of the six factors in the shelterin complex, which protects telomeres from being recognized as DNA damages. TRF1 and TRF2, two other shelterin proteins, have been shown to participate in DNA DSB repair at non-telomeric regions, but whether POT1, which binds to single strand telomeric DNA at chromosomal ends, is involved in DNA DSB repair has not been assessed. Here we found that POT1 arrives at DNA damage sites upon the occurrence of DNA DSBs. It suppresses the efficiency of nonhomologous end joining (NHEJ), the major pathway for fixing DNA DSBs in mammals, but surprisingly promotes NHEJ fidelity. Mechanistic studies indicate that POT1 facilitates the recruitment of Artemis, which is a nuclease and promotes fidelity of NHEJ, to DNA damage sites. In addition, we found that overexpression of POT1 inhibits the protein stability of Lig3, which is the major regulator of alternative NHEJ (alt-NHEJ), therefore suppressing the efficiency of alt-NHEJ. Taken together we propose that POT1 is a key factor regulating the balance between the efficiency and fidelity of NHEJ at non-telomeric DNA regions.
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Affiliation(s)
- Yang Yu
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Rong Tan
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Qian Ren
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
| | - Boya Gao
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Zhejin Sheng
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
| | - Juanlian Zhang
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
| | - Xiaoqing Zheng
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
| | - Ying Jiang
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
| | - Li Lan
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Zhiyong Mao
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
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