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Libra A, Sciacca E, Muscato G, Sambataro G, Spicuzza L, Vancheri C. Highlights on Future Treatments of IPF: Clues and Pitfalls. Int J Mol Sci 2024; 25:8392. [PMID: 39125962 PMCID: PMC11313529 DOI: 10.3390/ijms25158392] [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: 06/09/2024] [Revised: 07/22/2024] [Accepted: 07/28/2024] [Indexed: 08/12/2024] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease characterized by irreversible scarring of lung tissue, leading to death. Despite recent advancements in understanding its pathophysiology, IPF remains elusive, and therapeutic options are limited and non-curative. This review aims to synthesize the latest research developments, focusing on the molecular mechanisms driving the disease and on the related emerging treatments. Unfortunately, several phase 2 studies showing promising preliminary results did not meet the primary endpoints in the subsequent phase 3, underlying the complexity of the disease and the need for new integrated endpoints. IPF remains a challenging condition with a complex interplay of genetic, epigenetic, and pathophysiological factors. Ongoing research into the molecular keystones of IPF is critical for the development of targeted therapies that could potentially stop the progression of the disease. Future directions include personalized medicine approaches, artificial intelligence integration, growth in genetic insights, and novel drug targets.
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Affiliation(s)
- Alessandro Libra
- Department of Clinical and Experimental Medicine, Regional Referral Center for Rare Lung Disease, Policlinico “G. Rodolico-San Marco”, University of Catania, 95123 Catania, CT, Italy; (A.L.); (E.S.); (G.M.); (L.S.)
| | - Enrico Sciacca
- Department of Clinical and Experimental Medicine, Regional Referral Center for Rare Lung Disease, Policlinico “G. Rodolico-San Marco”, University of Catania, 95123 Catania, CT, Italy; (A.L.); (E.S.); (G.M.); (L.S.)
| | - Giuseppe Muscato
- Department of Clinical and Experimental Medicine, Regional Referral Center for Rare Lung Disease, Policlinico “G. Rodolico-San Marco”, University of Catania, 95123 Catania, CT, Italy; (A.L.); (E.S.); (G.M.); (L.S.)
| | - Gianluca Sambataro
- Artroreuma s.r.l., Rheumatology Outpatient Clinic, 95030 Mascalucia, CT, Italy;
| | - Lucia Spicuzza
- Department of Clinical and Experimental Medicine, Regional Referral Center for Rare Lung Disease, Policlinico “G. Rodolico-San Marco”, University of Catania, 95123 Catania, CT, Italy; (A.L.); (E.S.); (G.M.); (L.S.)
| | - Carlo Vancheri
- Department of Clinical and Experimental Medicine, Regional Referral Center for Rare Lung Disease, Policlinico “G. Rodolico-San Marco”, University of Catania, 95123 Catania, CT, Italy; (A.L.); (E.S.); (G.M.); (L.S.)
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2
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Kipcak A, Sezan S, Karpat O, Kaya E, Baylan S, Sariyar E, Yandim C, Karagonlar ZF. Suppression of CTC1 inhibits hepatocellular carcinoma cell growth and enhances RHPS4 cytotoxicity. Mol Biol Rep 2024; 51:799. [PMID: 39001931 DOI: 10.1007/s11033-024-09756-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 06/25/2024] [Indexed: 07/15/2024]
Abstract
BACKGROUND Although DNA repair mechanisms function to maintain genomic integrity, in cancer cells these mechanisms may negatively affect treatment efficiency. The strategy of targeting cancer cells via inhibiting DNA damage repair has been successfully used in breast and ovarian cancer using PARP inhibitors. Unfortunately, such strategies have not yet yielded results in liver cancer. Hepatocellular carcinoma (HCC), the most common type of liver cancer, is a treatment-resistant malignancy. Despite the development of guided therapies, treatment regimens for advanced HCC patients still fall short of the current need and significant problems such as cancer relapse with resistance still exist. In this paper, we targeted telomeric replication protein CTC1, which is responsible for telomere maintenance. METHODS CTC expression was analyzed using tumor and matched-tissue RNA-sequencing data from TCGA and GTEx. In HCC cell lines, q-RT-PCR and Western blotting were used to detect CTC1 expression. The knock-down of CTC1 was achieved using lentiviral plasmids. The effects of CTC1 silencing on HCC cells were analyzed by flow cytometry, MTT, spheroid and colony formation assays. RESULTS CTC1 is significantly downregulated in HCC tumor samples. However, CTC1 protein levels were higher in sorafenib-resistant cell lines compared to the parental groups. CTC1 inhibition reduced cell proliferation in sorafenib-resistant HCC cell lines and diminished their spheroid and colony forming capacities. Moreover, these cells were more sensitive to single and combined drug treatment with G4 stabilizer RHPS4 and sorafenib. CONCLUSION Our results suggest that targeting CTC1 might be a viable option for combinational therapies designed for sorafenib resistant HCC patients.
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Affiliation(s)
- Arda Kipcak
- Department of Genetics and Bioengineering, Izmir University of Economics, Sakarya Cad, İzmir, Turkey
- Department of Psychology, University of Virginia, Charlottesville, VA, USA
| | - Sila Sezan
- Division of Bioengineering, Graduate School, İzmir University of Economics, Sakarya Cad, İzmir, Turkey
| | - Ozum Karpat
- Department of Genetics and Bioengineering, Izmir University of Economics, Sakarya Cad, İzmir, Turkey
| | - Ezgi Kaya
- Department of Genetics and Bioengineering, Izmir University of Economics, Sakarya Cad, İzmir, Turkey
| | - Sude Baylan
- Department of Genetics and Bioengineering, Izmir University of Economics, Sakarya Cad, İzmir, Turkey
| | - Ece Sariyar
- Division of Bioengineering, Graduate School, İzmir University of Economics, Sakarya Cad, İzmir, Turkey
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Izmir, Turkey
| | - Cihangir Yandim
- Department of Genetics and Bioengineering, Izmir University of Economics, Sakarya Cad, İzmir, Turkey
| | - Zeynep Firtina Karagonlar
- Department of Genetics and Bioengineering, Izmir University of Economics, Sakarya Cad, İzmir, Turkey.
- Division of Bioengineering, Graduate School, İzmir University of Economics, Sakarya Cad, İzmir, Turkey.
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Hakobyan M, Binder H, Arakelyan A. Pan-cancer analysis of telomere maintenance mechanisms. J Biol Chem 2024; 300:107392. [PMID: 38763334 PMCID: PMC11225560 DOI: 10.1016/j.jbc.2024.107392] [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: 01/19/2024] [Revised: 04/28/2024] [Accepted: 05/13/2024] [Indexed: 05/21/2024] Open
Abstract
Telomeres, protective caps at chromosome ends, maintain genomic stability and control cell lifespan. Dysregulated telomere maintenance mechanisms (TMMs) are cancer hallmarks, enabling unchecked cell proliferation. We conducted a pan-cancer evaluation of TMM using RNA sequencing data from The Cancer Genome Atlas for 33 different cancer types and analyzed the activities of telomerase-dependent (TEL) and alternative lengthening of telomeres (ALT) TMM pathways in detail. To further characterize the TMM profiles, we categorized the tumors based on their ALT and TEL TMM pathway activities into five major phenotypes: ALT high TEL low, ALT low TEL low, ALT middle TEL middle, ALT high TEL high, and ALT low TEL high. These phenotypes refer to variations in telomere maintenance strategies, shedding light on the heterogeneous nature of telomere regulation in cancer. Moreover, we investigated the clinical implications of TMM phenotypes by examining their associations with clinical characteristics and patient outcomes. Specific TMM profiles were linked to specific survival patterns, emphasizing the potential of TMM profiling as a prognostic indicator and aiding in personalized cancer treatment strategies. Gene ontology analysis of the TMM phenotypes unveiled enriched biological processes associated with cell cycle regulation (both TEL and ALT), DNA replication (TEL), and chromosome dynamics (ALT) showing that telomere maintenance is tightly intertwined with cellular processes governing proliferation and genomic stability. Overall, our study provides an overview of the complexity of transcriptional regulation of telomere maintenance mechanisms in cancer.
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Affiliation(s)
- Meline Hakobyan
- Bioinformatics Group, Institute of Molecular Biology NAS RA, Yerevan, Armenia.
| | - Hans Binder
- Interdisciplinary Centre for Bioinformatics, University of Leipzig, Leipzig, Germany; Armenian Bioinformatics Institute, Yerevan, Armenia
| | - Arsen Arakelyan
- Bioinformatics Group, Institute of Molecular Biology NAS RA, Yerevan, Armenia
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4
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Schellnegger M, Hofmann E, Carnieletto M, Kamolz LP. Unlocking longevity: the role of telomeres and its targeting interventions. FRONTIERS IN AGING 2024; 5:1339317. [PMID: 38333665 PMCID: PMC10850353 DOI: 10.3389/fragi.2024.1339317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/11/2024] [Indexed: 02/10/2024]
Abstract
Average life expectancy has been steadily increasing in developed countries worldwide. These demographic changes are associated with an ever-growing social and economic strain to healthcare systems as well as society. The aging process typically manifests as a decline in physiological and cognitive functions, accompanied by a rise in chronic diseases. Consequently, strategies that both mitigate age-related diseases and promote healthy aging are urgently needed. Telomere attrition, characterized by the shortening of telomeres with each cell division, paradoxically serves as both a protective mechanism and a contributor to tissue degeneration and age-related ailments. Based on the essential role of telomere biology in aging, research efforts aim to develop approaches designed to counteract telomere attrition, aiming to delay or reduce age-related diseases. In this review, telomere biology and its role in aging and age-related diseases is summarized along with recent approaches to interfere with telomere shortening aiming at well- and healthy-aging as well as longevity. As aging research enters a new era, this review emphasizes telomere-targeting therapeutics, including telomerase activators and tankyrase inhibitors, while also exploring the effects of antioxidative and anti-inflammatory agents, along with indirectly related approaches like statins.
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Affiliation(s)
- Marlies Schellnegger
- Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Graz, Austria
- COREMED–Centre for Regenerative and Precision Medicine, JOANNEUM RESEARCH Forschungsgesellschaft mbH, Graz, Austria
| | - Elisabeth Hofmann
- Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Graz, Austria
- COREMED–Centre for Regenerative and Precision Medicine, JOANNEUM RESEARCH Forschungsgesellschaft mbH, Graz, Austria
- Research Unit for Tissue Regeneration, Repair and Reconstruction, Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Graz, Austria
| | - Martina Carnieletto
- Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Graz, Austria
- COREMED–Centre for Regenerative and Precision Medicine, JOANNEUM RESEARCH Forschungsgesellschaft mbH, Graz, Austria
| | - Lars-Peter Kamolz
- Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Graz, Austria
- COREMED–Centre for Regenerative and Precision Medicine, JOANNEUM RESEARCH Forschungsgesellschaft mbH, Graz, Austria
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5
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Palamarchuk AI, Kovalenko EI, Streltsova MA. Multiple Actions of Telomerase Reverse Transcriptase in Cell Death Regulation. Biomedicines 2023; 11:biomedicines11041091. [PMID: 37189709 DOI: 10.3390/biomedicines11041091] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/25/2023] [Accepted: 04/02/2023] [Indexed: 04/07/2023] Open
Abstract
Telomerase reverse transcriptase (TERT), a core part of telomerase, has been known for a long time only for its telomere lengthening function by reverse transcription of RNA template. Currently, TERT is considered as an intriguing link between multiple signaling pathways. The diverse intracellular localization of TERT corresponds to a wide range of functional activities. In addition to the canonical function of protecting chromosome ends, TERT by itself or as a part of the telomerase complex participates in cell stress responses, gene regulation and mitochondria functioning. Upregulation of TERT expression and increased telomerase activity in cancer and somatic cells relate to improved survival and persistence of such cells. In this review, we summarize the data for a comprehensive understanding of the role of TERT in cell death regulation, with a focus on the interaction of TERT with signaling pathways involved in cell survival and stress response.
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Affiliation(s)
- Anastasia I. Palamarchuk
- Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Elena I. Kovalenko
- Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Maria A. Streltsova
- Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
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Matsuda Y, Ye J, Yamakawa K, Mukai Y, Azuma K, Wu L, Masutomi K, Yamashita T, Daigo Y, Miyagi Y, Yokose T, Oshima T, Ito H, Morinaga S, Kishida T, Minamoto T, Kojima M, Kaneko S, Haba R, Kontani K, Kanaji N, Okano K, Muto-Ishizuka M, Yokohira M, Saoo K, Imaida K, Suizu F. Association of longer telomere length in cancer cells and cancer-associated fibroblasts with worse prognosis. J Natl Cancer Inst 2023; 115:208-218. [PMID: 36567450 PMCID: PMC9905972 DOI: 10.1093/jnci/djac226] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 06/02/2022] [Accepted: 11/28/2022] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Telomere dysfunction has been reported to be directly involved in carcinogenesis owing to chromosomal instability and immortalization; however, the clinicopathological significance of telomeres remains controversial. We have shown that telomere shortening occurs in normal-appearing duct cells at initiation and then continues during the progression of pancreatic cancer. In this study, we determined the clinicopathological and prognostic value of telomere length (TL) in cancer progression. METHODS TL in both cancer cells and cancer-associated fibroblasts (CAFs) was analyzed by high-throughput quantitative fluorescence in situ hybridization using a previously reported cohort comprising 1434 cases of adenocarcinoma (ADC), squamous cell carcinoma (SCC), adenosquamous carcinoma, hepatocellular carcinoma, and renal cell carcinoma (RCC), which are known cancers with a statistically significantly low incidence of alternative lengthening of telomeres. Cases were divided into 2 groups as follows: longer and shorter telomeres, according to the median TL of cancer cells and CAFs. The statistical significance of TL in cancer cells and CAFs on clinicopathological characteristics and prognosis was analyzed. RESULTS There was a close association between TL in cancer cells and CAFs. Longer telomeres in cancer cells and CAFs were associated with aggressive features such as advanced stage, high mitosis score and nuclear score, poorly differentiated cancer, and desmoplastic stroma in ADC. Furthermore, a longer TL was an independent prognostic factor for ADC, SCC, and RCC. CONCLUSIONS Longer telomeres are associated with worse prognosis in ADC, SCC, and RCC. Thus, TL is a novel biomarker for the diagnosis of aggressive cancers with poor prognoses.
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Affiliation(s)
- Yoko Matsuda
- Oncology Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Juanjuan Ye
- Oncology Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Keiko Yamakawa
- Oncology Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Yuri Mukai
- Oncology Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Kazuki Azuma
- Oncology Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Linxuan Wu
- Oncology Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
- Department of Plastic Surgery, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Kenkichi Masutomi
- Division of Cancer Stem Cell, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan
| | - Taro Yamashita
- Department of Gastroenterology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Ishikawa, Japan
| | - Yataro Daigo
- Department of Medical Oncology and Cancer Center
- Center for Advanced Medicine Against Cancer, Shiga University of Medical Science, Otsu, Shiga, Japan
- Center for Antibody and Vaccine Therapy, Research Hospital, Institute of Medical Science Hospital, The University of Tokyo, Tokyo, Japan
| | - Yohei Miyagi
- Kanagawa Cancer Center Research Institute, Asahi-ku, Yokohama, Japan
| | - Tomoyuki Yokose
- Department of Pathology, Kanagawa Cancer Center, Asahi-ku, Yokohama, Japan
| | - Takashi Oshima
- Department of Gastrointestinal Surgery, Kanagawa Cancer Center, Asahi-ku, Yokohama, Japan
| | - Hiroyuki Ito
- Department of Thoracic Surgery, Kanagawa Cancer Center, Asahi-ku, Yokohama, Japan
| | - Soichiro Morinaga
- Department of Hepato-Biliary and Pancreatic Surgery, Kanagawa Cancer Center, Asahi-ku, Yokohama, Japan
| | - Takeshi Kishida
- Department of Urology, Kanagawa Cancer Center, Asahi-ku, Yokohama, Japan
| | - Toshinari Minamoto
- Divison of Translational and Clinical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Japan
| | - Motohiro Kojima
- Division of Pathology, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, Kashiwa-shi, Chiba, Japan
| | - Shuichi Kaneko
- Department of Gastroenterology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Ishikawa, Japan
| | - Reiji Haba
- Diagnostic Pathology, Kagawa University, Kita-gun, Kagawa, Japan
| | - Keiichi Kontani
- Department of Thoracic, Breast and Endocrine Surgery, Kagawa University, Kita-gun, Kagawa, Japan
| | - Nobuhiro Kanaji
- Department of Internal Medicine, Division of Hematology, Rheumatology and Respiratory Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Keiichi Okano
- Department of Gastroenterological Surgery, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Mariko Muto-Ishizuka
- Oncology Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Masanao Yokohira
- Oncology Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Kousuke Saoo
- Oncology Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Katsumi Imaida
- Oncology Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
| | - Futoshi Suizu
- Oncology Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun, Kagawa, Japan
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Alonso-Gonzalez A, Tosco-Herrera E, Molina-Molina M, Flores C. Idiopathic pulmonary fibrosis and the role of genetics in the era of precision medicine. Front Med (Lausanne) 2023; 10:1152211. [PMID: 37181377 PMCID: PMC10172674 DOI: 10.3389/fmed.2023.1152211] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 04/03/2023] [Indexed: 05/16/2023] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a chronic, rare progressive lung disease, characterized by lung scarring and the irreversible loss of lung function. Two anti-fibrotic drugs, nintedanib and pirfenidone, have been demonstrated to slow down disease progression, although IPF mortality remains a challenge and the patients die after a few years from diagnosis. Rare pathogenic variants in genes that are involved in the surfactant metabolism and telomere maintenance, among others, have a high penetrance and tend to co-segregate with the disease in families. Common recurrent variants in the population with modest effect sizes have been also associated with the disease risk and progression. Genome-wide association studies (GWAS) support at least 23 genetic risk loci, linking the disease pathogenesis with unexpected molecular pathways including cellular adhesion and signaling, wound healing, barrier function, airway clearance, and innate immunity and host defense, besides the surfactant metabolism and telomere biology. As the cost of high-throughput genomic technologies continuously decreases and new technologies and approaches arise, their widespread use by clinicians and researchers is efficiently contributing to a better understanding of the pathogenesis of progressive pulmonary fibrosis. Here we provide an overview of the genetic factors known to be involved in IPF pathogenesis and discuss how they will continue to further advance in this field. We also discuss how genomic technologies could help to further improve IPF diagnosis and prognosis as well as for assessing genetic risk in unaffected relatives. The development and validation of evidence-based guidelines for genetic-based screening of IPF will allow redefining and classifying this disease relying on molecular characteristics and contribute to the implementation of precision medicine approaches.
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Affiliation(s)
- Aitana Alonso-Gonzalez
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
- Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - Eva Tosco-Herrera
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Maria Molina-Molina
- Servei de Pneumologia, Laboratori de Pneumologia Experimental, IDIBELL, Barcelona, Spain
- Campus de Bellvitge, Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Carlos Flores
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
- Genomics Division, Instituto Tecnológico y de Energías Renovables (ITER), Santa Cruz de Tenerife, Spain
- Facultad de Ciencias de la Salud, Universidad Fernando Pessoa Canarias, Las Palmas de Gran Canaria, Spain
- *Correspondence: Carlos Flores,
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8
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Tirelli C, Pesenti C, Miozzo M, Mondoni M, Fontana L, Centanni S. The Genetic and Epigenetic Footprint in Idiopathic Pulmonary Fibrosis and Familial Pulmonary Fibrosis: A State-of-the-Art Review. Diagnostics (Basel) 2022; 12:diagnostics12123107. [PMID: 36553114 PMCID: PMC9777399 DOI: 10.3390/diagnostics12123107] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/29/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a rare disease of the lung with a largely unknown etiology and a poor prognosis. Intriguingly, forms of familial pulmonary fibrosis (FPF) have long been known and linked to specific genetic mutations. There is little evidence of the possible role of genetics in the etiology of sporadic IPF. We carried out a non-systematic, narrative literature review aimed at describing the main known genetic and epigenetic mechanisms that are involved in the pathogenesis and prognosis of IPF and FPF. In this review, we highlighted the mutations in classical genes associated with FPF, including those encoding for telomerases (TERT, TERC, PARN, RTEL1), which are also found in about 10-20% of cases of sporadic IPF. In addition to the Mendelian forms, mutations in the genes encoding for the surfactant proteins (SFTPC, SFTPA1, SFTPA2, ABCA3) and polymorphisms of genes for the mucin MUC5B and the Toll-interacting protein TOLLIP are other pathways favoring the fibrogenesis that have been thoroughly explored. Moreover, great attention has been paid to the main epigenetic alterations (DNA methylation, histone modification and non-coding RNA gene silencing) that are emerging to play a role in fibrogenesis. Finally, a gaze on the shared mechanisms between cancer and fibrogenesis, and future perspectives on the genetics of pulmonary fibrosis have been analyzed.
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Affiliation(s)
- Claudio Tirelli
- Respiratory Unit, ASST Santi Paolo e Carlo, Department of Health Sciences, University of Milan, 20142 Milan, Italy
- Correspondence:
| | - Chiara Pesenti
- Medical Genetics Unit, ASST Santi Paolo e Carlo, Department of Health Sciences, University of Milan, 20142 Milan, Italy
| | - Monica Miozzo
- Medical Genetics Unit, ASST Santi Paolo e Carlo, Department of Health Sciences, University of Milan, 20142 Milan, Italy
| | - Michele Mondoni
- Respiratory Unit, ASST Santi Paolo e Carlo, Department of Health Sciences, University of Milan, 20142 Milan, Italy
| | - Laura Fontana
- Medical Genetics Unit, ASST Santi Paolo e Carlo, Department of Health Sciences, University of Milan, 20142 Milan, Italy
| | - Stefano Centanni
- Respiratory Unit, ASST Santi Paolo e Carlo, Department of Health Sciences, University of Milan, 20142 Milan, Italy
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9
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Yu EY, Cheung NKV, Lue NF. Connecting telomere maintenance and regulation to the developmental origin and differentiation states of neuroblastoma tumor cells. J Hematol Oncol 2022; 15:117. [PMID: 36030273 PMCID: PMC9420296 DOI: 10.1186/s13045-022-01337-w] [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: 06/02/2022] [Accepted: 07/28/2022] [Indexed: 11/18/2022] Open
Abstract
A cardinal feature that distinguishes clinically high-risk neuroblastoma from low-risk tumors is telomere maintenance. Specifically, neuroblastoma tumors with either active telomerase or alternative lengthening of telomeres exhibit aggressive growth characteristics that lead to poor outcomes, whereas tumors without telomere maintenance can be managed with observation or minimal treatment. Even though the need for cancer cells to maintain telomere DNA-in order to sustain cell proliferation-is well established, recent studies suggest that the neural crest origin of neuroblastoma may enforce unique relationships between telomeres and tumor malignancy. Specifically in neuroblastoma, telomere structure and telomerase activity are correlated with the adrenergic/mesenchymal differentiation states, and manipulating telomerase activity can trigger tumor cell differentiation. Both findings may reflect features of normal neural crest development. This review summarizes recent advances in the characterization of telomere structure and telomere maintenance mechanisms in neuroblastoma and discusses the findings in the context of relevant literature on telomeres during embryonic and neural development. Understanding the canonical and non-canonical roles of telomere maintenance in neuroblastoma could reveal vulnerabilities for telomere-directed therapies with potential applications to other pediatric malignancies.
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Affiliation(s)
- Eun Young Yu
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Nai-Kong V Cheung
- Department of Pediatrics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Neal F Lue
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.
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10
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Villarinho NJ, Vasconcelos FDC, Mazzoccoli L, da Silva Robaina MC, Pessoa LS, Siqueira PET, Maia RC, de Oliveira DM, Leite de Sampaio E Spohr TC, Lopes GF. Effects of long-term exposure to MST-312 on lung cancer cells tumorigenesis: Role of SHH/GLI-1 axis. Cell Biol Int 2022; 46:1468-1479. [PMID: 35811464 DOI: 10.1002/cbin.11843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 01/26/2022] [Accepted: 04/25/2022] [Indexed: 11/12/2022]
Abstract
Replicative immortality is a key feature of cancer cells and it is maintained by the expression of telomerase, a promising target of novel therapies. Long-term telomerase inhibition can induce resistance, but the mechanisms underlying this process remain unclear. The Sonic hedgehog pathway (SHH) is an embryogenic pathway involved in tumorigenesis and modulates the transcription of telomerase. We evaluated the effects of long-term treatment of the telomerase inhibitor MST-312 in morphology, proliferation, resistance, and in the SHH pathway molecules expression levels in lung cancer cells. Cells treated for 12 weeks with MST-312 showed changes in morphology, such as spindle-shaped cells, and a shift in the distribution of F-ACTIN from cortical to diffuse. Treatment also significantly reduced cells' efficiency to form spheroids and their clonogenic potential, independently of the cell cycle and telomeric DNA content. Moreover, GLI-1 expression levels were significantly reduced after 12 weeks of MST-312 treatment, indicating a possible inhibition of this signaling axis in the SHH pathway, without hindering NANOG and OCT4 expression. Here, we described a novel implication of long-term treatment with MST-312 functionally and molecularly, shedding new light on the molecular mechanisms of this drug in vitro.
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Affiliation(s)
- Nicolas Jones Villarinho
- Laboratório de Biomedicina do Cérebro, Instituto Estadual do Cérebro Paulo Niemeyer IECPN, Rio de Janeiro, Rio de Janeiro, Brazil.,Programa de Pós-graduação em Medicina (Anatomia Patológica), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Flavia da Cunha Vasconcelos
- Laboratório de Hemato-oncologia Celular e Molecular, Coordenação de Pesquisa, Instituto Nacional do Câncer, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luciano Mazzoccoli
- Laboratório de Hemato-oncologia Celular e Molecular, Coordenação de Pesquisa, Instituto Nacional do Câncer, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcela Cristina da Silva Robaina
- Laboratório de Hemato-oncologia Celular e Molecular, Coordenação de Pesquisa, Instituto Nacional do Câncer, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luciana Santos Pessoa
- Laboratório de Biomedicina do Cérebro, Instituto Estadual do Cérebro Paulo Niemeyer IECPN, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Pablo Enrique Torres Siqueira
- Laboratório de Biomedicina do Cérebro, Instituto Estadual do Cérebro Paulo Niemeyer IECPN, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Raquel Ciuvalschi Maia
- Laboratório de Hemato-oncologia Celular e Molecular, Coordenação de Pesquisa, Instituto Nacional do Câncer, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Diego Madureira de Oliveira
- Departamento de Bases Biológicas da Saúde, Universidade Federal de Brasília-Campus Ceilândia, Brasilia, Brazil
| | - Tania Cristina Leite de Sampaio E Spohr
- Laboratório de Biomedicina do Cérebro, Instituto Estadual do Cérebro Paulo Niemeyer IECPN, Rio de Janeiro, Rio de Janeiro, Brazil.,Programa de Pós-graduação em Medicina (Anatomia Patológica), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Giselle Faria Lopes
- Programa de Pós-graduação em Medicina (Anatomia Patológica), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.,Laboratório de Hemato-oncologia Celular e Molecular, Coordenação de Pesquisa, Instituto Nacional do Câncer, Rio de Janeiro, Rio de Janeiro, Brazil.,Divisão de Bioprodutos, Departamento de Biotecnologia Marinha, Instituto de Estudos do Mar Almirante Paulo Moreira (IEAPM), Arraial do Cabo, Brazil
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11
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Lu R, Pickett HA. Telomeric replication stress: the beginning and the end for alternative lengthening of telomeres cancers. Open Biol 2022; 12:220011. [PMID: 35259951 PMCID: PMC8905155 DOI: 10.1098/rsob.220011] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Telomeres are nucleoprotein structures that cap the ends of linear chromosomes. Telomeric DNA comprises terminal tracts of G-rich tandem repeats, which are inherently difficult for the replication machinery to navigate. Structural aberrations that promote activation of the alternative lengthening of telomeres (ALT) pathway of telomere maintenance exacerbate replication stress at ALT telomeres, driving fork stalling and fork collapse. This form of telomeric DNA damage perpetuates recombination-mediated repair pathways and break-induced telomere synthesis. The relationship between replication stress and DNA repair is tightly coordinated for the purpose of regulating telomere length in ALT cells, but has been shown to be experimentally manipulatable. This raises the intriguing possibility that induction of replication stress can be used as a means to cause toxic levels of DNA damage at ALT telomeres, thereby selectively disrupting the viability of ALT cancers.
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Affiliation(s)
- Robert Lu
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Hilda A. Pickett
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
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12
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Macek P, Wieckiewicz M, Poreba R, Gac P, Bogunia-Kubik K, Dratwa M, Wojakowska A, Mazur G, Martynowicz H. Assessment of Telomerase Reverse Transcriptase Single Nucleotide Polymorphism in Sleep Bruxism. J Clin Med 2022; 11:jcm11030525. [PMID: 35159976 PMCID: PMC8836512 DOI: 10.3390/jcm11030525] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/16/2022] [Accepted: 01/19/2022] [Indexed: 02/04/2023] Open
Abstract
Introduction: Sleep bruxism (SB) is a widespread masticatory muscle activity during sleep and affects approximately 13.2% of the general population. Telomerase reverse transcriptase (TERT) plays a role in preventing the shortening of the telomere. This prospective, observational study aimed to investigate the relationship between single nucleotide polymorphism (SNP) of TERT and the severity of SB and to identify the independent risk factors for SB. Methods: A total of 112 patients were diagnosed by performing one-night polysomnography based on the guidelines of the American Academy of Sleep Medicine. TERT SNP was detected by real-time quantitative polymerase chain reaction (qPCR). Results: Statistical analysis showed the lack of relationship between the rs2853669 polymorphism of TERT and severity of SB (p > 0.05). However, the study showed that patients with allele T in the 2736100 polymorphism of TERT had a lower score on the phasic bruxism episode index (BEI). Based on the receiver operating characteristic (ROC) curve, the value of phasic BEI was 0.8 for the differential prediction for the presence of allele T in the locus. The sensitivity and specificity were 0.328 and 0.893, respectively. The regression analysis showed that lack of TERT rs2736100 T allele, male gender, and arterial hypertension are the risk factors for the higher value of phasic BEI. Conclusion: The SNP of the TERT gene affects phasic SB intensity. The absence of TERT rs2736100 T allele, male sex, and arterial hypertension are independent risk factors for phasic SB.
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Affiliation(s)
- Piotr Macek
- Department of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology, Wroclaw Medical University, 50-556 Wroclaw, Poland; (P.M.); (R.P.); (A.W.); (G.M.); (H.M.)
| | - Mieszko Wieckiewicz
- Department of Experimental Dentistry, Wroclaw Medical University, 50-425 Wroclaw, Poland
- Correspondence:
| | - Rafal Poreba
- Department of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology, Wroclaw Medical University, 50-556 Wroclaw, Poland; (P.M.); (R.P.); (A.W.); (G.M.); (H.M.)
| | - Pawel Gac
- Department of Population Health, Division of Environmental Health and Occupational Medicine, Wroclaw Medical University, 50-345 Wroclaw, Poland;
| | - Katarzyna Bogunia-Kubik
- Laboratory of Clinical Immunogenetics and Pharmacogenetics, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wroclaw, Poland; (K.B.-K.); (M.D.)
| | - Marta Dratwa
- Laboratory of Clinical Immunogenetics and Pharmacogenetics, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wroclaw, Poland; (K.B.-K.); (M.D.)
| | - Anna Wojakowska
- Department of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology, Wroclaw Medical University, 50-556 Wroclaw, Poland; (P.M.); (R.P.); (A.W.); (G.M.); (H.M.)
| | - Grzegorz Mazur
- Department of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology, Wroclaw Medical University, 50-556 Wroclaw, Poland; (P.M.); (R.P.); (A.W.); (G.M.); (H.M.)
| | - Helena Martynowicz
- Department of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology, Wroclaw Medical University, 50-556 Wroclaw, Poland; (P.M.); (R.P.); (A.W.); (G.M.); (H.M.)
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13
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Zhang K, Xu L, Cong YS. Telomere Dysfunction in Idiopathic Pulmonary Fibrosis. Front Med (Lausanne) 2021; 8:739810. [PMID: 34859008 PMCID: PMC8631932 DOI: 10.3389/fmed.2021.739810] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 10/05/2021] [Indexed: 12/14/2022] Open
Abstract
Idiopathic pulmonary fibrosis is an age-dependent progressive and fatal lung disease of unknown etiology, which is characterized by the excessive accumulation of extracellular matrix inside the interstitial layer of the lung parenchyma that leads to abnormal scar architecture and compromised lung function capacity. Recent genetic studies have attributed the pathological genes or genetic mutations associated with familial idiopathic pulmonary fibrosis (IPF) and sporadic IPF to telomere-related components, suggesting that telomere dysfunction is an important determinant of this disease. In this study, we summarized recent advances in our understanding of how telomere dysfunction drives IPF genesis. We highlighted the key role of alveolar stem cell dysfunction caused by telomere shortening or telomere uncapping, which bridged the gap between telomere abnormalities and fibrotic lung pathology. We emphasized that senescence-associated secretory phenotypes, innate immune cell infiltration, and/or inflammation downstream of lung stem cell dysfunction influenced the native microenvironment and local cell signals, including increased transforming growth factor-beta (TGF-β) signaling in the lung, to induce pro-fibrotic conditions. In addition, the failed regeneration of new alveoli due to alveolar stem cell dysfunction might expose lung cells to elevated mechanical tension, which could activate the TGF-β signaling loop to promote the fibrotic process, especially in a periphery-to-center pattern as seen in IPF patients. Understanding the telomere-related molecular and pathophysiological mechanisms of IPF would provide new insights into IPF etiology and therapeutic strategies for this fatal disease.
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Affiliation(s)
- Kexiong Zhang
- Key Laboratory of Aging and Cancer Biology of Zhejiang Province, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, China
| | - Lu Xu
- Key Laboratory of Aging and Cancer Biology of Zhejiang Province, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, China
| | - Yu-Sheng Cong
- Key Laboratory of Aging and Cancer Biology of Zhejiang Province, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, China
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14
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Higa M, Matsuda Y, Fujii J, Sugimoto N, Yoshida K, Fujita M. TRF2-mediated ORC recruitment underlies telomere stability upon DNA replication stress. Nucleic Acids Res 2021; 49:12234-12251. [PMID: 34761263 PMCID: PMC8643664 DOI: 10.1093/nar/gkab1004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 10/07/2021] [Accepted: 10/12/2021] [Indexed: 12/12/2022] Open
Abstract
Telomeres are intrinsically difficult-to-replicate region of eukaryotic chromosomes. Telomeric repeat binding factor 2 (TRF2) binds to origin recognition complex (ORC) to facilitate the loading of ORC and the replicative helicase MCM complex onto DNA at telomeres. However, the biological significance of the TRF2–ORC interaction for telomere maintenance remains largely elusive. Here, we employed a TRF2 mutant with mutations in two acidic acid residues (E111A and E112A) that inhibited the TRF2–ORC interaction in human cells. The TRF2 mutant was impaired in ORC recruitment to telomeres and showed increased replication stress-associated telomeric DNA damage and telomere instability. Furthermore, overexpression of an ORC1 fragment (amino acids 244–511), which competitively inhibited the TRF2–ORC interaction, increased telomeric DNA damage under replication stress conditions. Taken together, these findings suggest that TRF2-mediated ORC recruitment contributes to the suppression of telomere instability.
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Affiliation(s)
- Mitsunori Higa
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yukihiro Matsuda
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Jumpei Fujii
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Nozomi Sugimoto
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kazumasa Yoshida
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Masatoshi Fujita
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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15
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Rachakonda S, Hoheisel JD, Kumar R. Occurrence, functionality and abundance of the TERT promoter mutations. Int J Cancer 2021; 149:1852-1862. [PMID: 34313327 DOI: 10.1002/ijc.33750] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 06/14/2021] [Accepted: 07/16/2021] [Indexed: 12/18/2022]
Abstract
Telomere shortening at chromosomal ends due to the constraints of the DNA replication process acts as a tumor suppressor by restricting the replicative potential in primary cells. Cancers evade that limitation primarily through the reactivation of telomerase via different mechanisms. Mutations within the promoter of the telomerase reverse transcriptase (TERT) gene represent a definite mechanism for the ribonucleic enzyme regeneration predominantly in cancers that arise from tissues with low rates of self-renewal. The promoter mutations cause a moderate increase in TERT transcription and consequent telomerase upregulation to the levels sufficient to delay replicative senescence but not prevent bulk telomere shortening and genomic instability. Since the discovery, a staggering number of studies have resolved the discrete aspects, effects and clinical relevance of the TERT promoter mutations. The promoter mutations link transcription of TERT with oncogenic pathways, associate with markers of poor outcome and define patients with reduced survivals in several cancers. In this review, we discuss the occurrence and impact of the promoter mutations and highlight the mechanism of TERT activation. We further deliberate on the foundational question of the abundance of the TERT promoter mutations and a general dearth of functional mutations within noncoding sequences, as evident from pan-cancer analysis of the whole-genomes. We posit that the favorable genomic constellation within the TERT promoter may be less than a common occurrence in other noncoding functional elements. Besides, the evolutionary constraints limit the functional fraction within the human genome, hence the lack of abundant mutations outside the coding sequences.
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Affiliation(s)
| | - Jörg D Hoheisel
- Division of Functional Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Rajiv Kumar
- Division of Functional Genome Analysis, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Department of Molecular Biology of Cancer, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czech Republic
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16
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Carrino S, Hennecker CD, Murrieta AC, Mittermaier A. Frustrated folding of guanine quadruplexes in telomeric DNA. Nucleic Acids Res 2021; 49:3063-3076. [PMID: 33693924 PMCID: PMC8034632 DOI: 10.1093/nar/gkab140] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 01/22/2021] [Accepted: 02/19/2021] [Indexed: 11/23/2022] Open
Abstract
Human chromosomes terminate in long, single-stranded, DNA overhangs of the repetitive sequence (TTAGGG)n. Sets of four adjacent TTAGGG repeats can fold into guanine quadruplexes (GQ), four-stranded structures that are implicated in telomere maintenance and cell immortalization and are targets in cancer therapy. Isolated GQs have been studied in detail, however much less is known about folding in long repeat sequences. Such chains adopt an enormous number of configurations containing various arrangements of GQs and unfolded gaps, leading to a highly frustrated energy landscape. To better understand this phenomenon, we used mutagenesis, thermal melting, and global analysis to determine stability, kinetic, and cooperativity parameters for GQ folding within chains containing 8–12 TTAGGG repeats. We then used these parameters to simulate the folding of 32-repeat chains, more representative of intact telomeres. We found that a combination of folding frustration and negative cooperativity between adjacent GQs increases TTAGGG unfolding by up to 40-fold, providing an abundance of unfolded gaps that are potential binding sites for telomeric proteins. This effect was most pronounced at the chain termini, which could promote telomere extension by telomerase. We conclude that folding frustration is an important and largely overlooked factor controlling the structure of telomeric DNA.
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Affiliation(s)
- Simone Carrino
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada
| | - Christopher D Hennecker
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada
| | - Ana C Murrieta
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada.,School of Engineering and Sciences, Instituto Tecnológico y de Estudios Superiores De Monterrey, Av. Eugenio Garza Sada 2501 Sur Col. Tecnológico C.P. 64849, Monterrey, Nuevo León, México
| | - Anthony Mittermaier
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, H3A 0B8, Canada
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17
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Nersisyan L, Simonyan A, Binder H, Arakelyan A. Telomere Maintenance Pathway Activity Analysis Enables Tissue- and Gene-Level Inferences. Front Genet 2021; 12:662464. [PMID: 33897770 PMCID: PMC8058386 DOI: 10.3389/fgene.2021.662464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/16/2021] [Indexed: 12/31/2022] Open
Abstract
Telomere maintenance is one of the mechanisms ensuring indefinite divisions of cancer and stem cells. Good understanding of telomere maintenance mechanisms (TMM) is important for studying cancers and designing therapies. However, molecular factors triggering selective activation of either the telomerase dependent (TEL) or the alternative lengthening of telomeres (ALT) pathway are poorly understood. In addition, more accurate and easy-to-use methodologies are required for TMM phenotyping. In this study, we have performed literature based reconstruction of signaling pathways for the ALT and TEL TMMs. Gene expression data were used for computational assessment of TMM pathway activities and compared with experimental assays for TEL and ALT. Explicit consideration of pathway topology makes bioinformatics analysis more informative compared to computational methods based on simple summary measures of gene expression. Application to healthy human tissues showed high ALT and TEL pathway activities in testis, and identified genes and pathways that may trigger TMM activation. Our approach offers a novel option for systematic investigation of TMM activation patterns across cancers and healthy tissues for dissecting pathway-based molecular markers with diagnostic impact.
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Affiliation(s)
- Lilit Nersisyan
- Bioinformatics Group, Institute of Molecular Biology, National Academy of Sciences, Yerevan, Armenia.,Pathverse, Yerevan, Armenia
| | - Arman Simonyan
- Bioinformatics Group, Institute of Molecular Biology, National Academy of Sciences, Yerevan, Armenia
| | - Hans Binder
- Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany
| | - Arsen Arakelyan
- Bioinformatics Group, Institute of Molecular Biology, National Academy of Sciences, Yerevan, Armenia.,Pathverse, Yerevan, Armenia
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18
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Lue NF. Duplex Telomere-Binding Proteins in Fungi With Canonical Telomere Repeats: New Lessons in the Rapid Evolution of Telomere Proteins. Front Genet 2021; 12:638790. [PMID: 33719348 PMCID: PMC7952879 DOI: 10.3389/fgene.2021.638790] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 02/08/2021] [Indexed: 01/04/2023] Open
Abstract
The telomere protein assemblies in different fungal lineages manifest quite profound structural and functional divergence, implying a high degree of flexibility and adaptability. Previous comparative analyses of fungal telomeres have focused on the role of telomere sequence alterations in promoting the evolution of corresponding proteins, particularly in budding and fission yeast. However, emerging evidence suggests that even in fungi with the canonical 6-bp telomere repeat unit, there are significant remodeling of the telomere assembly. Indeed, a new protein family can be recruited to serve dedicated telomere functions, and then experience subsequent loss in sub-branches of the clade. An especially interesting example is the Tay1 family of proteins, which emerged in fungi prior to the divergence of basidiomycetes from ascomycetes. This relatively recent protein family appears to have acquired its telomere DNA-binding activity through the modification of another Myb-containing protein. Members of the Tay1 family evidently underwent rather dramatic functional diversification, serving, e.g., as transcription factors in fission yeast while acting to promote telomere maintenance in basidiomycetes and some hemi-ascomycetes. Remarkably, despite its distinct structural organization and evolutionary origin, a basidiomycete Tay1 appears to promote telomere replication using the same mechanism as mammalian TRF1, i.e., by recruiting and regulating Blm helicase activity. This apparent example of convergent evolution at the molecular level highlight the ability of telomere proteins to acquire new interaction targets. The remarkable evolutionary history of Tay1 illustrates the power of protein modularity and the facile acquisition of nucleic acid/protein-binding activity to promote telomere flexibility.
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Affiliation(s)
- Neal F Lue
- Department of Microbiology and Immunology, W. R. Hearst Microbiology Research Center, New York, NY, United States.,Sandra and Edward Meyer Cancer Center, Weill Medical College of Cornell University, New York, NY, United States
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19
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Raghunandan M, Geelen D, Majerova E, Decottignies A. NHP2 downregulation counteracts hTR-mediated activation of the DNA damage response at ALT telomeres. EMBO J 2021; 40:e106336. [PMID: 33595114 DOI: 10.15252/embj.2020106336] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 11/09/2022] Open
Abstract
About 10% of cancer cells employ the "alternative lengthening of telomeres" (ALT) pathway instead of re-activating the hTERT subunit of human telomerase. The hTR RNA subunit is also abnormally silenced in some ALT+ cells not expressing hTERT, suggesting a possible negative non-canonical impact of hTR on ALT. Indeed, we show that ectopically expressed hTR reduces phosphorylation of ssDNA-binding protein RPA (p-RPAS33 ) at ALT telomeres by promoting the hnRNPA1- and DNA-PK-dependent depletion of RPA. The resulting defective ATR checkpoint signaling at telomeres impairs recruitment of the homologous recombination protein, RAD51. This induces ALT telomere fragility, increases POLD3-dependent C-circle production, and promotes the recruitment of the DNA damage marker 53BP1. In ALT+ cells that naturally retain hTR expression, NHP2 H/ACA ribonucleoprotein levels are downregulated, likely in order to restrain DNA damage response (DDR) activation at telomeres through reduced 53BP1 recruitment. This unexpected role of NHP2 is independent from hTR's non-canonical function in modulating telomeric p-RPAS33 . Collectively, our study shines new light on the interference between telomerase- and ALT-dependent pathways and unravels a crucial role for hTR and NHP2 in DDR regulation at ALT telomeres.
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Affiliation(s)
- Maya Raghunandan
- Genetic and Epigenetic Alterations of Genomes, de Duve Institute, Faculty of Pharmacy and Biomedical Sciences, Université catholique de Louvain, Brussels, Belgium
| | - Dan Geelen
- Genetic and Epigenetic Alterations of Genomes, de Duve Institute, Faculty of Pharmacy and Biomedical Sciences, Université catholique de Louvain, Brussels, Belgium
| | - Eva Majerova
- Genetic and Epigenetic Alterations of Genomes, de Duve Institute, Faculty of Pharmacy and Biomedical Sciences, Université catholique de Louvain, Brussels, Belgium
| | - Anabelle Decottignies
- Genetic and Epigenetic Alterations of Genomes, de Duve Institute, Faculty of Pharmacy and Biomedical Sciences, Université catholique de Louvain, Brussels, Belgium
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20
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Xie W, Zhu H, Zhao M, Wang L, Li S, Zhao C, Zhou Y, Zhu B, Jiang X, Liu W, Ren C. Crucial roles of different RNA-binding hnRNP proteins in Stem Cells. Int J Biol Sci 2021; 17:807-817. [PMID: 33767590 PMCID: PMC7975692 DOI: 10.7150/ijbs.55120] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 01/07/2021] [Indexed: 11/05/2022] Open
Abstract
The self-renewal, pluripotency and differentiation of stem cells are regulated by various genetic and epigenetic factors. As a kind of RNA binding protein (RBP), the heterogeneous nuclear ribonucleoproteins (hnRNPs) can act as "RNA scaffold" and recruit mRNA, lncRNA, microRNA and circRNA to affect mRNA splicing and processing, regulate gene transcription and post-transcriptional translation, change genome structure, and ultimately play crucial roles in the biological processes of cells. Recent researches have demonstrated that hnRNPs are irreplaceable for self-renewal and differentiation of stem cells. hnRNPs function in stem cells by multiple mechanisms, which include regulating mRNA stability, inducing alternative splicing of mRNA, epigenetically regulate gene expression, and maintaining telomerase activity and telomere length. The functions and the underlying mechanisms of hnRNPs in stem cells deserve further investigation.
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Affiliation(s)
- Wen Xie
- Cancer Research Institute, Department of Neurosurgery, School of Basic Medical Science, Xiangya Hospital, Central South University, Changsha 410008, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Central South University, Changsha 410008, China
| | - Hecheng Zhu
- Cancer Research Institute, Department of Neurosurgery, School of Basic Medical Science, Xiangya Hospital, Central South University, Changsha 410008, China.,Changsha Kexin Cancer Hospital, Changsha, Hunan 410205, China
| | - Ming Zhao
- Changsha Kexin Cancer Hospital, Changsha, Hunan 410205, China
| | - Lei Wang
- Cancer Research Institute, Department of Neurosurgery, School of Basic Medical Science, Xiangya Hospital, Central South University, Changsha 410008, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Central South University, Changsha 410008, China
| | - Shasha Li
- Cancer Research Institute, Department of Neurosurgery, School of Basic Medical Science, Xiangya Hospital, Central South University, Changsha 410008, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Central South University, Changsha 410008, China
| | - Cong Zhao
- Cancer Research Institute, Department of Neurosurgery, School of Basic Medical Science, Xiangya Hospital, Central South University, Changsha 410008, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Central South University, Changsha 410008, China
| | - Yao Zhou
- Cancer Research Institute, Department of Neurosurgery, School of Basic Medical Science, Xiangya Hospital, Central South University, Changsha 410008, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Central South University, Changsha 410008, China
| | - Bin Zhu
- Cancer Research Institute, Department of Neurosurgery, School of Basic Medical Science, Xiangya Hospital, Central South University, Changsha 410008, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Central South University, Changsha 410008, China
| | - Xingjun Jiang
- Cancer Research Institute, Department of Neurosurgery, School of Basic Medical Science, Xiangya Hospital, Central South University, Changsha 410008, China.,Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Weidong Liu
- Cancer Research Institute, Department of Neurosurgery, School of Basic Medical Science, Xiangya Hospital, Central South University, Changsha 410008, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Central South University, Changsha 410008, China
| | - Caiping Ren
- Cancer Research Institute, Department of Neurosurgery, School of Basic Medical Science, Xiangya Hospital, Central South University, Changsha 410008, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health and the Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Central South University, Changsha 410008, China
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21
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Yu EY, Zahid SS, Ganduri S, Sutherland JH, Hsu M, Holloman WK, Lue NF. Structurally distinct telomere-binding proteins in Ustilago maydis execute non-overlapping functions in telomere replication, recombination, and protection. Commun Biol 2020; 3:777. [PMID: 33328546 PMCID: PMC7744550 DOI: 10.1038/s42003-020-01505-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 11/20/2020] [Indexed: 11/09/2022] Open
Abstract
Duplex telomere binding proteins exhibit considerable structural and functional diversity in fungi. Herein we interrogate the activities and functions of two Myb-containing, duplex telomere repeat-binding factors in Ustilago maydis, a basidiomycete that is evolutionarily distant from the standard fungi. These two telomere-binding proteins, UmTay1 and UmTrf2, despite having distinct domain structures, exhibit comparable affinities and sequence specificity for the canonical telomere repeats. UmTay1 specializes in promoting telomere replication and an ALT-like pathway, most likely by modulating the helicase activity of Blm. UmTrf2, in contrast, is critical for telomere protection; transcriptional repression of Umtrf2 leads to severe growth defects and profound telomere aberrations. Comparative analysis of UmTay1 homologs in different phyla reveals broad functional diversity for this protein family and provides a case study for how DNA-binding proteins can acquire and lose functions at various chromosomal locations. Our findings also point to stimulatory effect of telomere protein on ALT in Ustilago maydis that may be conserved in other systems.
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Affiliation(s)
- Eun Young Yu
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Syed S Zahid
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Swapna Ganduri
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Jeanette H Sutherland
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Min Hsu
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - William K Holloman
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Neal F Lue
- Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA. .,Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.
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22
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Study of Cellular Aging in a Cohort of Patients with Heart Failure. High Blood Press Cardiovasc Prev 2020; 28:49-55. [PMID: 33315189 DOI: 10.1007/s40292-020-00421-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 10/28/2020] [Indexed: 10/22/2022] Open
Abstract
INTRODUCTION Cellular senescence and fibrosis are important phenomena in the development of heart failure (HF). These processes are closely related to telomeric length (TL). AIM To assess cellular senescence in HF through the study of TL in peripheral blood mononuclear cells (PBMCs). METHODS Using real-time PCR, TL was measured in PBMCs from 20 patients diagnosed with HF, aged between 51 and 77 years (50% males). Ten patients had HF with reduced ejection fraction (HFrEF) and ten had preserved EF (HFpEF). TL was measured in 20 healthy controls matched by age and gender. Obtained values were compared with an internal control, the 36B4 gene, which never modifies its expression, and correlated with the clinical parameters. RESULTS TL mean was 1327 in patients with HF (95% CI 1309-1344) compared to 1286 (95% CI 1264-1308) in controls (p = 0.005). No differences were found when studying the correlation of telomere size with subgroups by gender, left ventricle ejection fraction (LVEF), presence of ischemic heart disease, smoking, Chronic Obstructive Pulmonary Disease (COPD), NYHA stage, degree of renal function or number of hospital admissions in the previous year. A significant and negative correlation was found between age and renal function (r = - 0.544, p < 0.05), as well as LVEF and NT-proBNP values (ρ = - 0.475, p < 0.05). CONCLUSIONS TL is shorter in patients with HF when compared with age and gender balanced controls. The shortening of TL is independent of age, gender and degree of kidney function, and does not correlate with LVEF decrease or functional status.
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23
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Fani L, Hilal S, Sedaghat S, Broer L, Licher S, Arp PP, van Meurs JBJ, Ikram MK, Ikram MA. Telomere Length and the Risk of Alzheimer's Disease: The Rotterdam Study. J Alzheimers Dis 2020; 73:707-714. [PMID: 31839608 PMCID: PMC7029372 DOI: 10.3233/jad-190759] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
There is a wide interest in biomarkers that capture the burden of detrimental factors as these accumulate with the passage of time, i.e., increasing age. Telomere length has received considerable attention as such a marker, because it is easily quantified and it may aid in disentangling the etiology of dementia or serve as predictive marker. We determined the association of telomere length with risk of Alzheimer’s disease and all-cause dementia in a population-based setting. Within the Rotterdam Study, we performed quantitative PCR to measure mean leukocyte telomere length in blood. We determined the association of telomere length with risk of Alzheimer’s disease until 2016, using Cox regression models. Of 1,961 participants (mean age 71.4±9.3 years, 57.1% women) with a median follow-up of 8.3 years, 237 individuals were diagnosed with Alzheimer’s disease. We found a U-shaped association between telomere length and risk of Alzheimer’s disease: compared to the middle tertile the adjusted hazard ratio was 1.59 (95% confidence interval (CI), 1.13–2.23) for the lowest tertile and 1.47 (1.03–2.10) for the highest tertile. Results were similarly U-shaped but slightly attenuated for all-cause dementia. In conclusion, shorter and longer telomere length are both associated with an increased risk of Alzheimer’s disease in the general population.
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Affiliation(s)
- Lana Fani
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Saima Hilal
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands.,Department of Neurology, Erasmus MC, Rotterdam, The Netherlands
| | - Sanaz Sedaghat
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands.,Department of Preventive Medicine, Feinberg School of Medicine Northwestern University, Chicago, IL, USA
| | - Linda Broer
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Silvan Licher
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Pascal P Arp
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | | | - M Kamran Ikram
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands.,Department of Neurology, Erasmus MC, Rotterdam, The Netherlands
| | - M Arfan Ikram
- Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, The Netherlands
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24
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Stroik S, Kurtz K, Lin K, Karachenets S, Myers CL, Bielinsky AK, Hendrickson EA. EXO1 resection at G-quadruplex structures facilitates resolution and replication. Nucleic Acids Res 2020; 48:4960-4975. [PMID: 32232411 PMCID: PMC7229832 DOI: 10.1093/nar/gkaa199] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 02/08/2020] [Accepted: 03/16/2020] [Indexed: 01/25/2023] Open
Abstract
G-quadruplexes represent unique roadblocks to DNA replication, which tends to stall at these secondary structures. Although G-quadruplexes can be found throughout the genome, telomeres, due to their G-richness, are particularly predisposed to forming these structures and thus represent difficult-to-replicate regions. Here, we demonstrate that exonuclease 1 (EXO1) plays a key role in the resolution of, and replication through, telomeric G-quadruplexes. When replication forks encounter G-quadruplexes, EXO1 resects the nascent DNA proximal to these structures to facilitate fork progression and faithful replication. In the absence of EXO1, forks accumulate at stabilized G-quadruplexes and ultimately collapse. These collapsed forks are preferentially repaired via error-prone end joining as depletion of EXO1 diverts repair away from error-free homology-dependent repair. Such aberrant repair leads to increased genomic instability, which is exacerbated at chromosome termini in the form of dysfunction and telomere loss.
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Affiliation(s)
- Susanna Stroik
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel, Hill, NC 27514, USA
| | - Kevin Kurtz
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Kevin Lin
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Sergey Karachenets
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Chad L Myers
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Anja-Katrin Bielinsky
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Eric A Hendrickson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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25
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Modulation of telomerase expression and function by miRNAs: Anti-cancer potential. Life Sci 2020; 259:118387. [PMID: 32890603 DOI: 10.1016/j.lfs.2020.118387] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 08/24/2020] [Accepted: 08/30/2020] [Indexed: 12/11/2022]
Abstract
Telomerase is a nucleoprotein reverse transcriptase that maintains the telomere, a protective structure at the ends of the chromosome, and is active in cancer cells, stem cells, and fetal cells. Telomerase immortalizes cancer cells and induces unlimited cell division by preventing telomere shortening. Immortalized cancer cells have unlimited proliferative potential due to telomerase activity that causes tumorigenesis and malignancy. Therefore, telomerase can be a lucrative anti-cancer target. The regulation of catalytic subunit of telomerase (TERT) determines the extent of telomerase activity. miRNAs, as an endogenous regulator of gene expression, can control telomerase activity by targeting TERT mRNA. miRNAs that have a decreasing effect on TERT translation mediate modulation of telomerase activity in cancer cells by binding to TERT mRNA and regulating TERT translation. In this review, we provide an update on miRNAs that influence telomerase activity by regulation of TERT translation.
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26
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Vinayagamurthy S, Ganguly A, Chowdhury S. Extra-telomeric impact of telomeres: Emerging molecular connections in pluripotency or stemness. J Biol Chem 2020; 295:10245-10254. [PMID: 32444498 PMCID: PMC7383370 DOI: 10.1074/jbc.rev119.009710] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 05/21/2020] [Indexed: 12/26/2022] Open
Abstract
Telomeres comprise specialized nucleic acid-protein complexes that help protect chromosome ends from DNA damage. Moreover, telomeres associate with subtelomeric regions through looping. This results in altered expression of subtelomeric genes. Recent observations further reveal telomere length-dependent gene regulation and epigenetic modifications at sites spread across the genome and distant from telomeres. This regulation is mediated through the telomere-binding protein telomeric repeat-binding factor 2 (TRF2). These observations suggest a role of telomeres in extra-telomeric functions. Most notably, telomeres have a broad impact on pluripotency and differentiation. For example, cardiomyocytes differentiate with higher efficacy from induced pluripotent stem cells having long telomeres, and differentiated cells obtained from human embryonic stem cells with relatively long telomeres have a longer lifespan. Here, we first highlight reports on these two seemingly distinct research areas: the extra-telomeric role of telomere-binding factors and the role of telomeres in pluripotency/stemness. On the basis of the observations reported in these studies, we draw attention to potential molecular connections between extra-telomeric biology and pluripotency. Finally, in the context of the nonlocal influence of telomeres on pluripotency and stemness, we discuss major opportunities for progress in molecular understanding of aging-related disorders and neurodegenerative diseases.
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Affiliation(s)
- Soujanya Vinayagamurthy
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR Institute of Genomics and Integrative Biology, New Delhi, India
| | - Akansha Ganguly
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi, India
| | - Shantanu Chowdhury
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR Institute of Genomics and Integrative Biology, New Delhi, India
- G.N.R. Knowledge Centre for Genome Informatics, CSIR Institute of Genomics and Integrative Biology, New Delhi, India
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27
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Functional Diversification of Replication Protein A Paralogs and Telomere Length Maintenance in Arabidopsis. Genetics 2020; 215:989-1002. [PMID: 32532801 DOI: 10.1534/genetics.120.303222] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/05/2020] [Indexed: 12/14/2022] Open
Abstract
Replication protein A (RPA) is essential for many facets of DNA metabolism. The RPA gene family expanded in Arabidopsis thaliana with five phylogenetically distinct RPA1 subunits (RPA1A-E), two RPA2 (RPA2A and B), and two RPA3 (RPA3A and B). RPA1 paralogs exhibit partial redundancy and functional specialization in DNA replication (RPA1B and RPA1D), repair (RPA1C and RPA1E), and meiotic recombination (RPA1A and RPA1C). Here, we show that RPA subunits also differentially impact telomere length set point. Loss of RPA1 resets bulk telomeres at a shorter length, with a functional hierarchy for replication group over repair and meiosis group RPA1 subunits. Plants lacking RPA2A, but not RPA2B, harbor short telomeres similar to the replication group. Telomere shortening does not correlate with decreased telomerase activity or deprotection of chromosome ends in rpa mutants. However, in vitro assays show that RPA1B2A3B unfolds telomeric G-quadruplexes known to inhibit replications fork progression. We also found that ATR deficiency can partially rescue short telomeres in rpa2a mutants, although plants exhibit defects in growth and development. Unexpectedly, the telomere shortening phenotype of rpa2a mutants is completely abolished in plants lacking the RTEL1 helicase. RTEL1 has been implicated in a variety of nucleic acid transactions, including suppression of homologous recombination. Thus, the lack of telomere shortening in rpa2a mutants upon RTEL1 deletion suggests that telomere replication defects incurred by loss of RPA may be bypassed by homologous recombination. Taken together, these findings provide new insight into how RPA cooperates with replication and recombination machinery to sustain telomeric DNA.
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28
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Selected ellipticine derivatives, known to target topoisomerase II, suppress the alternative lengthening of telomere (ALT) pathway in telomerase-negative cells. J Cancer Res Clin Oncol 2020; 146:1671-1676. [PMID: 32333143 DOI: 10.1007/s00432-020-03213-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 04/07/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND DNA topoisomerase and telomerase enzymes are popular targets of several anti-tumor drugs. Smooth proceeding of telomeric recombination requires Topoisomerase II (Top2), which is involved in telomere-telomere recombination through functioning in relaxation of positive supercoils among the cells adopting telomerase-independent Alternative lengthening of telomere (ALT) pathway. Most of the inhibitors reported so far have been designed to targetsolely telomerase-positive cells, which can potentially lead to therapeutic failure because tumor cells treated with telomerase inhibitors can activate the ALT pathway for telomere maintenance. Knowing that ALT cells are more sensitive against a Top2 inhibitor, ICRF-93 agent, compared to telomerase-positive cells, we analyzed two selected ellipticine derivatives that we recently reported as TopII-targeting compounds, to assess their effects on the formation of DNA breaks and suppression of ALT pathway. METHODS Cell viability, Comet, C-Circle assays, dot blot, immunofluorescence staining, and telomere fluorescence in situ hybridization (FISH) staining were used for determining the effect of the compounds on ALT status of tumor cells. RESULTS AND CONCLUSIONS Treatment of ALT cells with ellipticine derivatives resulted in the formation of DNA breaks and suppression of ALT-associated phenotypes in vitro. Our results will contribute to the development of therapeutic strategies combining telomerase and ALT pathway inhibitors.
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29
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Prasad R, Pal D, Mohammad W. Therapeutic Targets in Telomerase and Telomere Biology of Cancers. Indian J Clin Biochem 2020; 35:135-146. [PMID: 32226245 PMCID: PMC7093628 DOI: 10.1007/s12291-020-00876-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Telomeres play an important role to conserve genomic integrity by protecting the ends of chromosomes in normal cells. Since, their progressive shortening during successive cell division which lead to chromosomal instability. Notably, telomere length is perpetuated by telomerase in large majority of cancers, thereby ensure indefinite cell proliferation-a hallmark of cancer-and this unique feature has provided telomerase as the preferred target for drug development in cancer therapeutics. Cancer cells have acquired the potential to have telomere length maintenance by telomerase activation- up-regulation of hTERT gene expression in tumor cells is synchronized by multiple genetic and epigenetic modification mechanisms viz hTERT structural variants, hTERT promoter mutation and epigenetic modifications through hTERT promoter methylation which have been implicated in various cancers initiation and progression. In view of these facts, strategies have been made to target the underlining molecular mechanisms involved in telomerase reactivation as well as of telomere structure with special reference to distortion of sheltrin proteins. This review is focussed on extensive understanding of telomere and telomerase biology. which will provide indispensable informations for enhancing the efficiency of rational anticancer drug design. However, there is also an urgent need for better understanding of cell signalling pathways for alternative lengthening of telomere which is present in telomerase negative cancer for therapeutic targets.
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Affiliation(s)
- Rajendra Prasad
- Department of Biochemistry, MM Institute of Medical Science and Research, MM (Deemed to be University), Mullana, Ambala, Haryana 133207 India
| | - Deeksha Pal
- Department of Translational and Regenerative Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, 160012 India
| | - Wajid Mohammad
- Department of Biochemistry, MM Institute of Medical Science and Research, MM (Deemed to be University), Mullana, Ambala, Haryana 133207 India
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30
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Grabuschnig S, Soh J, Heidinger P, Bachler T, Hirschböck E, Rosales Rodriguez I, Schwendenwein D, Sensen CW. Circulating cell-free DNA is predominantly composed of retrotransposable elements and non-telomeric satellite DNA. J Biotechnol 2020; 313:48-56. [DOI: 10.1016/j.jbiotec.2020.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/26/2020] [Accepted: 03/04/2020] [Indexed: 12/19/2022]
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31
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Trypanosoma brucei RAP1 Has Essential Functional Domains That Are Required for Different Protein Interactions. mSphere 2020; 5:5/1/e00027-20. [PMID: 32102938 PMCID: PMC7045384 DOI: 10.1128/msphere.00027-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Trypanosoma brucei causes human African trypanosomiasis and regularly switches its major surface antigen, VSG, to evade the host immune response. VSGs are expressed from subtelomeres in a monoallelic fashion. TbRAP1, a telomere protein, is essential for cell viability and VSG monoallelic expression and suppresses VSG switching. Although TbRAP1 has conserved functional domains in common with its orthologs from yeasts to mammals, the domain functions are unknown. RAP1 orthologs have pleiotropic functions, and interaction with different partners is an important means by which RAP1 executes its different roles. We have established a Cre-loxP-mediated conditional knockout system for TbRAP1 and examined the roles of various functional domains in protein expression, nuclear localization, and protein-protein interactions. This system enables further studies of TbRAP1 point mutation phenotypes. We have also determined functional domains of TbRAP1 that are required for several different protein interactions, shedding light on the underlying mechanisms of TbRAP1-mediated VSG silencing. RAP1 is a telomere protein that is well conserved from protozoa to mammals. It plays important roles in chromosome end protection, telomere length control, and gene expression/silencing at both telomeric and nontelomeric loci. Interaction with different partners is an important mechanism by which RAP1 executes its different functions in yeast. The RAP1 ortholog in Trypanosoma brucei is essential for variant surface glycoprotein (VSG) monoallelic expression, an important aspect of antigenic variation, where T. brucei regularly switches its major surface antigen, VSG, to evade the host immune response. Like other RAP1 orthologs, T. brucei RAP1 (TbRAP1) has conserved functional domains, including BRCA1 C terminus (BRCT), Myb, MybLike, and RAP1 C terminus (RCT). To study functions of various TbRAP1 domains, we established a strain in which one endogenous allele of TbRAP1 is flanked by loxP repeats, enabling its conditional deletion by Cre-mediated recombination. We replaced the other TbRAP1 allele with various mutant alleles lacking individual functional domains and examined their nuclear localization and protein interaction abilities. The N terminus, BRCT, and RCT of TbRAP1 are required for normal protein levels, while the Myb and MybLike domains are essential for normal cell growth. Additionally, the Myb domain of TbRAP1 is required for its interaction with T. brucei TTAGGG repeat-binding factor (TbTRF), while the BRCT domain is required for its self-interaction. Furthermore, the TbRAP1 MybLike domain contains a bipartite nuclear localization signal that is required for its interaction with importin α and its nuclear localization. Interestingly, RAP1’s self-interaction and the interaction between RAP1 and TRF are conserved from kinetoplastids to mammals. However, details of the interaction interfaces have changed throughout evolution. IMPORTANCETrypanosoma brucei causes human African trypanosomiasis and regularly switches its major surface antigen, VSG, to evade the host immune response. VSGs are expressed from subtelomeres in a monoallelic fashion. TbRAP1, a telomere protein, is essential for cell viability and VSG monoallelic expression and suppresses VSG switching. Although TbRAP1 has conserved functional domains in common with its orthologs from yeasts to mammals, the domain functions are unknown. RAP1 orthologs have pleiotropic functions, and interaction with different partners is an important means by which RAP1 executes its different roles. We have established a Cre-loxP-mediated conditional knockout system for TbRAP1 and examined the roles of various functional domains in protein expression, nuclear localization, and protein-protein interactions. This system enables further studies of TbRAP1 point mutation phenotypes. We have also determined functional domains of TbRAP1 that are required for several different protein interactions, shedding light on the underlying mechanisms of TbRAP1-mediated VSG silencing.
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32
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Xu C, Xie N, Su Y, Sun Z, Liang Y, Zhang N, Liu D, Jia S, Xing X, Han L, Li G, Tong T, Chen J. HnRNP F/H associate with hTERC and telomerase holoenzyme to modulate telomerase function and promote cell proliferation. Cell Death Differ 2019; 27:1998-2013. [PMID: 31863069 PMCID: PMC7244589 DOI: 10.1038/s41418-019-0483-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 12/09/2019] [Accepted: 12/10/2019] [Indexed: 12/16/2022] Open
Abstract
Human telomerase RNA component hTERC comprises multiple motifs that contribute to hTERC biogenesis, holoenzyme activity, and enzyme recruitment to telomeres. hTERC contains several guanine tracts (G-tracts) at its 5′-end, but its associated proteins and potential roles in telomerase function are still poorly understood. The heterogeneous nuclear ribonucleoproteins F, H1, and H2 (hnRNP F/H) are splicing factors that preferentially bind to poly(G)-rich sequences RNA. Here, we demonstrate that hnRNP F/H associate with both hTERC and telomerase holoenzyme to regulate telomerase activity. We reveal hnRNP F/H bind to the 5′-end region of hTERC in vitro and in vivo, and identify the first three G-tracts of hTERC and qRRM1 domain of hnRNP F/H are required for their interaction. Furthermore, hnRNP F/H also directly interact with telomerase holoenzyme. Functionally, we show that hnRNP F/H plays important roles in modulating telomerase activity and telomere length. Moreover, hnRNP F/H deletion greatly impair cancer and stem cell proliferation, and induce stem cell senescence, while hnRNP F/H overexpression delay stem cell senescence. Collectively, our findings unveil a novel role of hnRNP F/H as the binding partners of hTERC and telomerase holoenzyme to regulate telomerase function.
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Affiliation(s)
- Chenzhong Xu
- Peking University Research Center on Aging, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, Department of Integration of Chinese and Western Medicine, School of Basic Medical Science, Peking University, Beijing, 100191, China
| | - Nan Xie
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Peking University, Beijing, 100191, China
| | - Yuanyuan Su
- Peking University Research Center on Aging, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, Department of Integration of Chinese and Western Medicine, School of Basic Medical Science, Peking University, Beijing, 100191, China
| | - Zhaomeng Sun
- Peking University Research Center on Aging, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, Department of Integration of Chinese and Western Medicine, School of Basic Medical Science, Peking University, Beijing, 100191, China
| | - Yao Liang
- Peking University Research Center on Aging, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, Department of Integration of Chinese and Western Medicine, School of Basic Medical Science, Peking University, Beijing, 100191, China
| | - Na Zhang
- Peking University Research Center on Aging, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, Department of Integration of Chinese and Western Medicine, School of Basic Medical Science, Peking University, Beijing, 100191, China
| | - Doudou Liu
- Peking University Research Center on Aging, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, Department of Integration of Chinese and Western Medicine, School of Basic Medical Science, Peking University, Beijing, 100191, China
| | - Shuqin Jia
- Department of Molecular Diagnostics, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute, Beijing, 100142, China
| | - Xiaofang Xing
- Department of Molecular Diagnostics, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute, Beijing, 100142, China
| | - Limin Han
- Peking University Research Center on Aging, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, Department of Integration of Chinese and Western Medicine, School of Basic Medical Science, Peking University, Beijing, 100191, China
| | - Guodong Li
- Peking University Research Center on Aging, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, Department of Integration of Chinese and Western Medicine, School of Basic Medical Science, Peking University, Beijing, 100191, China
| | - Tanjun Tong
- Peking University Research Center on Aging, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, Department of Integration of Chinese and Western Medicine, School of Basic Medical Science, Peking University, Beijing, 100191, China
| | - Jun Chen
- Peking University Research Center on Aging, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, Department of Integration of Chinese and Western Medicine, School of Basic Medical Science, Peking University, Beijing, 100191, China.
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33
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Stroik S, Kurtz K, Hendrickson EA. CtIP is essential for telomere replication. Nucleic Acids Res 2019; 47:8927-8940. [PMID: 31378812 PMCID: PMC6755089 DOI: 10.1093/nar/gkz652] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/08/2019] [Accepted: 07/16/2019] [Indexed: 01/10/2023] Open
Abstract
The maintenance of telomere length is critical to longevity and survival. Specifically, the failure to properly replicate, resect, and/or form appropriate telomeric structures drives telomere shortening and, in turn, genomic instability. The endonuclease CtIP is a DNA repair protein that is well-known to promote genome stability through the resection of endogenous DNA double-stranded breaks. Here, we describe a novel role for CtIP. We show that in the absence of CtIP, human telomeres shorten rapidly to non-viable lengths. This telomere dysfunction results in an accumulation of fusions, breaks, and frank telomere loss. Additionally, CtIP suppresses the generation of circular, extrachromosomal telomeric DNA. These latter structures appear to arise from arrested DNA replication forks that accumulate in the absence of CtIP. Hence, CtIP is required for faithful replication through telomeres via its roles at stalled replication tracts. Our findings demonstrate a new role for CtIP as a protector of human telomere integrity.
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Affiliation(s)
- Susanna Stroik
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Kevin Kurtz
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Eric A Hendrickson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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34
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Telomere-associated genes and telomeric lncRNAs are biomarker candidates in lung squamous cell carcinoma (LUSC). Exp Mol Pathol 2019; 112:104354. [PMID: 31837325 DOI: 10.1016/j.yexmp.2019.104354] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 11/28/2019] [Accepted: 12/06/2019] [Indexed: 12/13/2022]
Abstract
In the past decade, research efforts were made to identify molecular biomarkers useful as therapeutic targets in Non-Small Cell Lung Cancer (NSCLC), the most frequent type of lung carcinoma. NSCLC presents different histological subtypes being the most prevalent LUSC (Lung Squamous Cell Cancer) and LUAD (Lung Adenocarcinoma), and only a subset of LUAD patients' present tumors expressing known targetable genetic alterations. Telomeres and its components, including telomerase, the enzyme that replenishes telomeres, have been considered potential cancer biomarkers due to their crucial role in cell proliferation and genome stability. Our study aims to quantify expression changes affecting telomere-associated genes and ncRNAs associated with telomere regulation and maintenance in NSCLC. We first assessed the transcriptome (RNA-Seq) data of NSCLC patients from The Cancer Genome Atlas (TCGA) and then we tested the expression of telomere-associated genes and telomeric ncRNAs (TERC, telomerase RNA component, and TERRA, telomere repeat-containing RNA) in Brazilian NCSLC patient samples by quantitative RT-PCR, using matched normal adjacent tissue samples as the control. We also estimated the mean size of terminal restriction fragments (TRF) of some Brazilian NSCLC patients using telomeric Southern blot. The TCGA analysis identified alterations in the expression profile of TERT and telomere damage repair genes, mainly in the LUSC subtype. The study of Brazilian NSCLC samples by RT-qPCR showed that LUSC and LUAD express high amounts of TERT and that although the mean TRF size of tumor samples was shorter compared to normal cells, telomeres in NSCLC are probably maintained by telomerase. Also, the expression analysis of Brazilian NSCLC samples identified statistically significant alterations in the expression of genes involved with telomere damage repair, as well as in TERC and TERRA, mainly in the LUSC subtype. We, therefore, concluded that telomere maintenance genes are significantly deregulated in NSCLC, representing potential biomarkers in the LUSC subtype.
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35
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Primo LMF, Teixeira LK. DNA replication stress: oncogenes in the spotlight. Genet Mol Biol 2019; 43:e20190138. [PMID: 31930281 PMCID: PMC7197996 DOI: 10.1590/1678-4685gmb-2019-0138] [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: 04/23/2019] [Accepted: 07/09/2019] [Indexed: 01/21/2023] Open
Abstract
Precise replication of genetic material is essential to maintain genome stability. DNA replication is a tightly regulated process that ensues faithful copies of DNA molecules to daughter cells during each cell cycle. Perturbation of DNA replication may compromise the transmission of genetic information, leading to DNA damage, mutations, and chromosomal rearrangements. DNA replication stress, also referred to as DNA replicative stress, is defined as the slowing or stalling of replication fork progression during DNA synthesis as a result of different insults. Oncogene activation, one hallmark of cancer, is able to disturb numerous cellular processes, including DNA replication. In fact, extensive work has indicated that oncogene-induced replication stress is an important source of genomic instability in human carcinogenesis. In this review, we focus on main oncogenes that induce DNA replication stress, such as RAS, MYC, Cyclin E, MDM2, and BCL-2 among others, and the molecular mechanisms by which these oncogenes interfere with normal DNA replication and promote genomic instability.
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Affiliation(s)
- Luiza M. F. Primo
- Group of Cell Cycle Control, Program of Immunology and Tumor
Biology. Brazilian National Cancer Institute (INCA), Rio de Janeiro, RJ,
Brazil
| | - Leonardo K. Teixeira
- Group of Cell Cycle Control, Program of Immunology and Tumor
Biology. Brazilian National Cancer Institute (INCA), Rio de Janeiro, RJ,
Brazil
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36
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Abstract
Precise replication of genetic material is essential to maintain genome stability. DNA replication is a tightly regulated process that ensues faithful copies of DNA molecules to daughter cells during each cell cycle. Perturbation of DNA replication may compromise the transmission of genetic information, leading to DNA damage, mutations, and chromosomal rearrangements. DNA replication stress, also referred to as DNA replicative stress, is defined as the slowing or stalling of replication fork progression during DNA synthesis as a result of different insults. Oncogene activation, one hallmark of cancer, is able to disturb numerous cellular processes, including DNA replication. In fact, extensive work has indicated that oncogene-induced replication stress is an important source of genomic instability in human carcinogenesis. In this review, we focus on main oncogenes that induce DNA replication stress, such as RAS, MYC, Cyclin E, MDM2, and BCL-2 among others, and the molecular mechanisms by which these oncogenes interfere with normal DNA replication and promote genomic instability.
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Affiliation(s)
- Luiza M F Primo
- Group of Cell Cycle Control, Program of Immunology and Tumor Biology. Brazilian National Cancer Institute (INCA), Rio de Janeiro, RJ, Brazil
| | - Leonardo K Teixeira
- Group of Cell Cycle Control, Program of Immunology and Tumor Biology. Brazilian National Cancer Institute (INCA), Rio de Janeiro, RJ, Brazil
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37
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Nersisyan L, Nikoghosyan M, Arakelyan A. WGS-based telomere length analysis in Dutch family trios implicates stronger maternal inheritance and a role for RRM1 gene. Sci Rep 2019; 9:18758. [PMID: 31822713 PMCID: PMC6904582 DOI: 10.1038/s41598-019-55109-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 11/24/2019] [Indexed: 12/14/2022] Open
Abstract
Telomere length (TL) regulation is an important factor in ageing, reproduction and cancer development. Genetic, hereditary and environmental factors regulating TL are currently widely investigated, however, their relative contribution to TL variability is still understudied. We have used whole genome sequencing data of 250 family trios from the Genome of the Netherlands project to perform computational measurement of TL and a series of regression and genome-wide association analyses to reveal TL inheritance patterns and associated genetic factors. Our results confirm that TL is a largely heritable trait, primarily with mother's, and, to a lesser extent, with father's TL having the strongest influence on the offspring. In this cohort, mother's, but not father's age at conception was positively linked to offspring TL. Age-related TL attrition of 40 bp/year had relatively small influence on TL variability. Finally, we have identified TL-associated variations in ribonuclease reductase catalytic subunit M1 (RRM1 gene), which is known to regulate telomere maintenance in yeast. We also highlight the importance of multivariate approach and the limitations of existing tools for the analysis of TL as a polygenic heritable quantitative trait.
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Affiliation(s)
- Lilit Nersisyan
- Bioinformatics Group, Institute of Molecular Biology NAS RA, 7 Hasratyan str., 0014, Yerevan, Armenia.
| | - Maria Nikoghosyan
- Bioinformatics Group, Institute of Molecular Biology NAS RA, 7 Hasratyan str., 0014, Yerevan, Armenia
- Institute of Biomedicine and Pharmacy, Russian-Armenian University, 123 Hovsep Emin St, 0051, Yerevan, Armenia
| | - Arsen Arakelyan
- Bioinformatics Group, Institute of Molecular Biology NAS RA, 7 Hasratyan str., 0014, Yerevan, Armenia
- Institute of Biomedicine and Pharmacy, Russian-Armenian University, 123 Hovsep Emin St, 0051, Yerevan, Armenia
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38
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Chen Y. The structural biology of the shelterin complex. Biol Chem 2019; 400:457-466. [PMID: 30352022 DOI: 10.1515/hsz-2018-0368] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/15/2018] [Indexed: 02/07/2023]
Abstract
The shelterin complex protects telomeric DNA and plays critical roles in maintaining chromosome stability. The structures and functions of the shelterin complex have been extensively explored in the past decades. This review summarizes the current progress on structural studies of shelterin complexes from different species. It focuses on the structural features and assembly of common structural domains, highlighting the evolutionary plasticity and conserved roles of shelterin proteins in telomere homeostasis and protection.
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Affiliation(s)
- Yong Chen
- State Key Laboratory of Molecular Biology, National Center for Protein Science Shanghai, Shanghai Science Research Center, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 333 Haike Road, Shanghai 201210, China.,School of Life Science and Technology, Shanghai Tech University, 100 Haike Road, Shanghai 201210, China
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39
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Li Y, Li X, Cao M, Jiang Y, Yan J, Liu Z, Yang R, Chen X, Sun P, Xiang R, Wang L, Shi Y. Seryl tRNA synthetase cooperates with POT1 to regulate telomere length and cellular senescence. Signal Transduct Target Ther 2019; 4:50. [PMID: 31815007 PMCID: PMC6882858 DOI: 10.1038/s41392-019-0078-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/04/2019] [Accepted: 04/23/2019] [Indexed: 12/13/2022] Open
Abstract
Deregulated telomere length is a causative factor in many physiological and pathological processes, including aging and cancer. Many studies focusing on telomeres have revealed important roles for cooperation between the Shelterin protein complex and telomerase in maintaining telomere length. However, it remains largely unknown whether and how aging-related stresses, such as deregulated protein homeostasis, impact telomere length. Here, we explored the possible roles of aminoacyl tRNA synthetases (AARSs), key enzymes catalyzing the first reactions in protein synthesis, in regulating telomere length and aging. We selected seryl tRNA synthetase (SerRS) since our previous studies discovered expanded functions of SerRS in the nucleus in addition to its canonical cytoplasmic role in protein synthesis. In this study, we revealed that overexpression of SerRS promoted cellular senescence and inhibited the growth of cervical tumor xenografts in mice by triggering the senescence of tumor cells. In the nucleus, SerRS directly bound to telomeric DNA repeats and tethered more POT1 proteins to telomeres through a direct interaction between the UNE-S domain of SerRS and the OB1 domain of POT1. We further demonstrated that SerRS-induced enrichment of POT1 prevented the recruitment of telomerase to telomeres, resulting in progressive telomere shortening. Our data suggested a possible molecular link between protein synthesis and telomere length control, the deregulation of which may be associated with aging and cancer.
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Affiliation(s)
- Yingxi Li
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin, 300071 China
| | - Xiyang Li
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin, 300071 China
| | - Mei Cao
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin, 300071 China
| | - Yuke Jiang
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin, 300071 China
| | - Jie Yan
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin, 300071 China
| | - Ze Liu
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin, 300071 China
| | - Rongcun Yang
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin, 300071 China
| | - Xu Chen
- Tianjin Key Laboratory Human Development and Reproductive Regulation, Nankai University Affiliated Hospital of Obstetrics and Gynecology, Tianjin, China
| | - Peiqing Sun
- Department of Cancer Biology, Wake Forest Comprehensive Cancer Center, Wake Forest School of Medicine, Winston-Salem, NC USA
| | - Rong Xiang
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin, 300071 China
| | - Longlong Wang
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin, 300071 China
- Tianjin Key Laboratory Human Development and Reproductive Regulation, Nankai University Affiliated Hospital of Obstetrics and Gynecology, Tianjin, China
| | - Yi Shi
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin, 300071 China
- Tianjin Key Laboratory Human Development and Reproductive Regulation, Nankai University Affiliated Hospital of Obstetrics and Gynecology, Tianjin, China
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40
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Jørgensen SW, Liberti SE, Larsen NB, Lisby M, Mankouri HW, Hickson ID. Esc2 promotes telomere stability in response to DNA replication stress. Nucleic Acids Res 2019; 47:4597-4611. [PMID: 30838410 PMCID: PMC6511870 DOI: 10.1093/nar/gkz158] [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] [Received: 10/14/2018] [Revised: 02/25/2019] [Accepted: 03/02/2019] [Indexed: 01/27/2023] Open
Abstract
Telomeric regions of the genome are inherently difficult-to-replicate due to their propensity to generate DNA secondary structures and form nucleoprotein complexes that can impede DNA replication fork progression. Precisely how cells respond to DNA replication stalling within a telomere remains poorly characterized, largely due to the methodological difficulties in analysing defined stalling events in molecular detail. Here, we utilized a site-specific DNA replication barrier mediated by the ‘Tus/Ter’ system to define the consequences of DNA replication perturbation within a single telomeric locus. Through molecular genetic analysis of this defined fork-stalling event, coupled with the use of a genome-wide genetic screen, we identified an important role for the SUMO-like domain protein, Esc2, in limiting genome rearrangements at a telomere. Moreover, we showed that these rearrangements are driven by the combined action of the Mph1 helicase and the homologous recombination machinery. Our findings demonstrate that chromosomal context influences cellular responses to a stalled replication fork and reveal protective factors that are required at telomeric loci to limit DNA replication stress-induced chromosomal instability.
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Affiliation(s)
- Signe W Jørgensen
- Center for Chromosome Stability, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, 2200 Copenhagen N, Denmark.,Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, 2200 Copenhagen N, Denmark
| | - Sascha E Liberti
- Center for Chromosome Stability, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, 2200 Copenhagen N, Denmark.,Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, 2200 Copenhagen N, Denmark
| | - Nicolai B Larsen
- Center for Chromosome Stability, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, 2200 Copenhagen N, Denmark.,Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, 2200 Copenhagen N, Denmark
| | - Michael Lisby
- Center for Chromosome Stability, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, 2200 Copenhagen N, Denmark.,Department of Biology, University of Copenhagen, Ole Maaløes Vej, 2200 Copenhagen N, Denmark
| | - Hocine W Mankouri
- Center for Chromosome Stability, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, 2200 Copenhagen N, Denmark.,Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, 2200 Copenhagen N, Denmark
| | - Ian D Hickson
- Center for Chromosome Stability, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, 2200 Copenhagen N, Denmark.,Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, 2200 Copenhagen N, Denmark
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41
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Dyskerin Mutations Present in Dyskeratosis Congenita Patients Increase Oxidative Stress and DNA Damage Signalling in Dictyostelium Discoideum. Cells 2019; 8:cells8111406. [PMID: 31717312 PMCID: PMC6912284 DOI: 10.3390/cells8111406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 12/17/2022] Open
Abstract
Dyskerin is a protein involved in the formation of small nucleolar and small Cajal body ribonucleoproteins. These complexes participate in RNA pseudouridylation and are also components of the telomerase complex required for telomere elongation. Dyskerin mutations cause a rare disease, X-linked dyskeratosis congenita, with no curative treatment. The social amoeba Dictyostelium discoideum contains a gene coding for a dyskerin homologous protein. In this article D. discoideum mutant strains that have mutations corresponding to mutations found in dyskeratosis congenita patients are described. The phenotype of the mutant strains has been studied and no alterations were observed in pseudouridylation activity and telomere structure. Mutant strains showed increased proliferation on liquid culture but reduced growth feeding on bacteria. The results obtained indicated the existence of increased DNA damage response and reactive oxygen species, as also reported in human Dyskeratosis congenita cells and some other disease models. These data, together with the haploid character of D. discoideum vegetative cells, that resemble the genomic structure of the human dyskerin gene, located in the X chromosome, support the conclusion that D. discoideum can be a good model system for the study of this disease.
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42
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Nersisyan L, Hopp L, Loeffler-Wirth H, Galle J, Loeffler M, Arakelyan A, Binder H. Telomere Length Maintenance and Its Transcriptional Regulation in Lynch Syndrome and Sporadic Colorectal Carcinoma. Front Oncol 2019; 9:1172. [PMID: 31750255 PMCID: PMC6848383 DOI: 10.3389/fonc.2019.01172] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Accepted: 10/18/2019] [Indexed: 12/14/2022] Open
Abstract
Background: Activation of telomere maintenance mechanisms (TMMs) is a hallmark of most cancers, and is required to prevent genome instability and to establish cellular immortality through reconstitution of capping of chromosome ends. TMM depends on the cancer type. Comparative studies linking tumor biology and TMM have potential impact for evaluating cancer onset and development. Methods: We have studied alterations of telomere length, their sequence composition and transcriptional regulation in mismatch repair deficient colorectal cancers arising in Lynch syndrome (LS-CRC) and microsatellite instable (MSI) sporadic CRC (MSI s-CRC), and for comparison, in microsatellite stable (MSS) s-CRC and in benign colon mucosa. Our study applied bioinformatics analysis of whole genome DNA and RNA sequencing data and a pathway model to study telomere length alterations and the potential effect of the "classical" telomerase (TEL-) and alternative (ALT-) TMM using transcriptomic signatures. Results: We have found progressive decrease of mean telomere length in all cancer subtypes compared with reference systems. Our results support the view that telomere attrition is an early event in tumorigenesis. TMM gets activated in all tumors studied due to concerted overexpression of a large fraction of genes with direct relation to telomere function, where only a very small fraction of them showed recurrent mutations. TEL-related transcriptional state was dominating in all CRC subtypes, showing, however, subtype-specific activation patterns; while contribution of the ALT-TMM was slightly more prominent in the hypermutated MSI s-CRC and LS-CRC. TEL-TMM is mainly activated by over-expression of DKC1 and/or TERT genes and their interaction partners, where DKC1 is more prominent in MSS than in MSI s-CRC and can serve as a transcriptomic marker of TMM activity. Conclusions: Our results suggest that transcriptional patterns are indicative for TMM pathway activation with subtle differences between TEL and ALT mechanisms in a CRC subtype-specific fashion. Sequencing data potentially provide a suited measure to study alterations of telomere length and of underlying transcriptional regulation. Further studies are needed to improve this method.
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Affiliation(s)
- Lilit Nersisyan
- Group of Bioinformatics, Institute of Molecular Biology, National Academy of Sciences, Yerevan, Armenia
| | - Lydia Hopp
- Interdisciplinary Centre for Bioinformatics, Leipzig University, Leipzig, Germany
| | - Henry Loeffler-Wirth
- Interdisciplinary Centre for Bioinformatics, Leipzig University, Leipzig, Germany
| | - Jörg Galle
- Interdisciplinary Centre for Bioinformatics, Leipzig University, Leipzig, Germany
| | - Markus Loeffler
- Interdisciplinary Centre for Bioinformatics, Leipzig University, Leipzig, Germany.,Institute for Medical Informatics, Statistics and Epidemiology, Leipzig University, Leipzig, Germany
| | - Arsen Arakelyan
- Group of Bioinformatics, Institute of Molecular Biology, National Academy of Sciences, Yerevan, Armenia
| | - Hans Binder
- Interdisciplinary Centre for Bioinformatics, Leipzig University, Leipzig, Germany
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43
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Saha A, Nanavaty VP, Li B. Telomere and Subtelomere R-loops and Antigenic Variation in Trypanosomes. J Mol Biol 2019; 432:4167-4185. [PMID: 31682833 DOI: 10.1016/j.jmb.2019.10.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 10/02/2019] [Accepted: 10/21/2019] [Indexed: 12/12/2022]
Abstract
Trypanosoma brucei is a kinetoplastid parasite that causes African trypanosomiasis, which is fatal if left untreated. T. brucei regularly switches its major surface antigen, VSG, to evade the host immune responses. VSGs are exclusively expressed from subtelomeric expression sites (ESs) where VSG genes are flanked by upstream 70 bp repeats and downstream telomeric repeats. The telomere downstream of the active VSG is transcribed into a long-noncoding RNA (TERRA), which forms RNA:DNA hybrids (R-loops) with the telomeric DNA. At an elevated level, telomere R-loops cause more telomeric and subtelomeric double-strand breaks (DSBs) and increase VSG switching rate. In addition, stabilized R-loops are observed at the 70 bp repeats and immediately downstream of ES-linked VSGs in RNase H defective cells, which also have an increased amount of subtelomeric DSBs and more frequent VSG switching. Although subtelomere plasticity is expected to be beneficial to antigenic variation, severe defects in subtelomere integrity and stability increase cell lethality. Therefore, regulation of the telomere and 70 bp repeat R-loop levels is important for the balance between antigenic variation and cell fitness in T. brucei. In addition, the high level of the active ES transcription favors accumulation of R-loops at the telomere and 70 bp repeats, providing an intrinsic mechanism for local DSB formation, which is a strong inducer of VSG switching.
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Affiliation(s)
- Arpita Saha
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Vishal P Nanavaty
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA; Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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44
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Hu Y, Bennett HW, Liu N, Moravec M, Williams JF, Azzalin CM, King MC. RNA-DNA Hybrids Support Recombination-Based Telomere Maintenance in Fission Yeast. Genetics 2019; 213:431-447. [PMID: 31405990 PMCID: PMC6781888 DOI: 10.1534/genetics.119.302606] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 08/09/2019] [Indexed: 11/18/2022] Open
Abstract
A subset of cancers rely on telomerase-independent mechanisms to maintain their chromosome ends. The predominant "alternative lengthening of telomeres" pathway appears dependent on homology-directed repair (HDR) to maintain telomeric DNA. However, the molecular changes needed for cells to productively engage in telomeric HDR are poorly understood. To gain new insights into this transition, we monitored the state of telomeres during serial culture of fission yeast (Schizosaccharomyces pombe) lacking the telomerase recruitment factor Ccq1. Rad52 is loaded onto critically short telomeres shortly after germination despite continued telomere erosion, suggesting that recruitment of recombination factors is not sufficient to maintain telomeres in the absence of telomerase function. Instead, survivor formation coincides with the derepression of telomeric repeat-containing RNA (TERRA). In this context, degradation of TERRA associated with the telomere in the form of R-loops drives a severe growth crisis, ultimately leading to a novel type of survivor with linear chromosomes and altered cytological telomere characteristics, including the loss of the shelterin component Rap1 (but not the TRF1/TRF2 ortholog, Taz1) from the telomere. We demonstrate that deletion of Rap1 is protective in this context, preventing the growth crisis that is otherwise triggered by degradation of telomeric R-loops in survivors with linear chromosomes. These findings suggest that upregulation of telomere-engaged TERRA, or altered recruitment of shelterin components, can support telomerase-independent telomere maintenance.
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Affiliation(s)
- Yan Hu
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520-8002
| | - Henrietta W Bennett
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520-8002
| | - Na Liu
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520-8002
| | - Martin Moravec
- Institute of Biochemistry (IBC), Eidgenössische Technische Hochschule Zürich (ETHZ), 8093, Switzerland
| | - Jessica F Williams
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520-8002
| | - Claus M Azzalin
- Instituto de Medicina Molecular João Lobo Antunes (iMM), Faculdade de Medicina da Universidade de Lisboa, 1649-028, Portugal
| | - Megan C King
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520-8002
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45
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Abstract
Maintenance of genome integrity is a key process in all organisms. DNA polymerases (Pols) are central players in this process as they are in charge of the faithful reproduction of the genetic information, as well as of DNA repair. Interestingly, all eukaryotes possess a large repertoire of polymerases. Three protein complexes, DNA Pol α, δ, and ε, are in charge of nuclear DNA replication. These enzymes have the fidelity and processivity required to replicate long DNA sequences, but DNA lesions can block their progression. Consequently, eukaryotic genomes also encode a variable number of specialized polymerases (between five and 16 depending on the organism) that are involved in the replication of damaged DNA, DNA repair, and organellar DNA replication. This diversity of enzymes likely stems from their ability to bypass specific types of lesions. In the past 10–15 years, our knowledge regarding plant DNA polymerases dramatically increased. In this review, we discuss these recent findings and compare acquired knowledge in plants to data obtained in other eukaryotes. We also discuss the emerging links between genome and epigenome replication.
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46
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Rodriguez-Centeno J, Manguán-García C, Perona R, Sastre L. Structure of Dictyostelium discoideum telomeres. Analysis of possible replication mechanisms. PLoS One 2019; 14:e0222909. [PMID: 31550289 PMCID: PMC6759168 DOI: 10.1371/journal.pone.0222909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 09/10/2019] [Indexed: 12/14/2022] Open
Abstract
Telomeres are nucleo-protein structures that protect the ends of eukaryotic chromosomes. They are not completely synthesized during DNA replication and are elongated by specific mechanisms. The structure of the telomeres and the elongation mechanism have not been determined in Dictyostelium discoideum. This organism presents extrachromosomal palindromic elements containing two copies of the rDNA, also present at the end of the chromosomes. In this article the structure of the terminal region of the rDNA is shown to consist of repetitions of the A(G)n sequence where the number of Gs is variable. These repeats extend as a 3’ single stranded region. The G-rich region is preceded by four tandem repetitions of two different DNA motifs. D. discoideum telomere reverse transcriptase homologous protein (TERTHP) presented RNase-sensitive enzymatic activity and was required to maintain telomere structure since terthp-mutant strains presented reorganizations of the DNA terminal regions. These modifications were different in several terthp-mutants and changed with their prolonged culture and subcloning. However, the terthp gene is not essential for D. discoideum proliferation. Telomeres could be maintained in terthp-mutant strains by homologous recombination mechanisms such as ALT (Alternative Lengthening of Telomeres) or HAATI (heterochromatin amplification-mediated and telomerase-independent). In agreement with this hypothesis, the expression of mRNAs coding for several proteins involved in homologous recombination was induced in terthp-mutant strains. Extrachromosomal rDNA could serve as substrate in these DNA homologous recombination reactions.
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Affiliation(s)
- Javier Rodriguez-Centeno
- Instituto de Investigaciones Biomédicas CSIC/UAM, C/ Arturo Duperier, IdiPaz, C/Pedro Rico, Madrid, Spain
| | - Cristina Manguán-García
- Instituto de Investigaciones Biomédicas CSIC/UAM, C/ Arturo Duperier, IdiPaz, C/Pedro Rico, Madrid, Spain
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Rosario Perona
- Instituto de Investigaciones Biomédicas CSIC/UAM, C/ Arturo Duperier, IdiPaz, C/Pedro Rico, Madrid, Spain
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Leandro Sastre
- Instituto de Investigaciones Biomédicas CSIC/UAM, C/ Arturo Duperier, IdiPaz, C/Pedro Rico, Madrid, Spain
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
- * E-mail:
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47
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Ahmed SM, Dröge P. Oncofetal HMGA2 attenuates genotoxic damage induced by topoisomerase II target compounds through the regulation of local DNA topology. Mol Oncol 2019; 13:2062-2078. [PMID: 31271486 PMCID: PMC6763970 DOI: 10.1002/1878-0261.12541] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/26/2019] [Accepted: 07/03/2019] [Indexed: 12/26/2022] Open
Abstract
Rapidly dividing cells maintain chromatin supercoiling homeostasis via two specialized classes of enzymes, DNA topoisomerase type 1 and 2 (TOP1/2). Several important anticancer drugs perturb this homeostasis by targeting TOP1/2, thereby generating genotoxic DNA damage. Our recent studies indicated that the oncofetal chromatin structuring high‐mobility group AT‐hook 2 (HMGA2) protein plays an important role as a DNA replication fork chaperone in coping with DNA topological ramifications that occur during replication stress, both genomewide and at fragile sites such as subtelomeres. Intriguingly, a recent large‐scale clinical study identified HMGA2 expression as a sole predicting marker for relapse and poor clinical outcomes in 350 acute myeloid leukemia (AML) patients receiving combinatorial treatments that targeted TOP2 and replicative DNA synthesis. Here, we demonstrate that HMGA2 significantly enhanced the DNA supercoil relaxation activity of the drug target TOP2A and that this activator function is mechanistically linked to HMGA2's known ability to constrain DNA supercoils within highly compacted ternary complexes. Furthermore, we show that HMGA2 significantly reduced genotoxic DNA damage in each tested cancer cell model during treatment with the TOP2A poison etoposide or the catalytic TOP2A inhibitor merbarone. Taken together with the recent clinical data obtained with AML patients targeted with TOP2 poisons, our study suggests a novel mechanism of cancer chemoresistance toward combination therapies administering TOP2 poisons or inhibitors. We therefore strongly argue for the future implementation of trials of HMGA2 expression profiling to stratify patients before finalizing clinical treatment regimes.
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Affiliation(s)
- Syed Moiz Ahmed
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Peter Dröge
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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Lagunas AM, Francis M, Maniar NB, Nikolova G, Wu J, Crowe DL. Paracrine Interaction of Cancer Stem Cell Populations Is Regulated by the Senescence-Associated Secretory Phenotype (SASP). Mol Cancer Res 2019; 17:1480-1492. [PMID: 31043491 DOI: 10.1158/1541-7786.mcr-18-1356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 03/25/2019] [Accepted: 04/25/2019] [Indexed: 11/16/2022]
Abstract
Dyskeratosis congenita is a telomere DNA damage syndrome characterized by defective telomere maintenance, bone marrow failure, and increased head and neck cancer risk. The Pot1b-/-;Terc+/- mouse exhibits some features of dyskeratosis congenita, but head and neck cancer was not reported in this model. To model the head and neck cancer phenotype, we created unique Pot1b- and p53-null-mutant models which allow genetic lineage tracing of two distinct stem cell populations. Loss of Pot1b expression depleted stem cells via ATR/Chk1/p53 signaling. Tumorigenesis was inhibited in Pot1b-/-;p53+/+ mice due to cellular senescence. Pot1b-/-;p53-/- tumors also exhibited senescence, but proliferated and metastasized with expansion of Lgr6+ stem cells indicative of senescence-associated secretory phenotype. Selective depletion of the small K15+ stem cell fraction resulted in reduction of Lgr6+ cells and inhibition of tumorigenesis via senescence. Gene expression studies revealed that K15+ cancer stem cells regulate Lgr6+ cancer stem cell expansion via chemokine signaling. Genetic ablation of the chemokine receptor Cxcr2 inhibited cancer stem cell expansion and tumorigenesis via senescence. The effects of chemokines were primarily mediated by PI3K signaling, which is a therapeutic target in head and neck cancer. IMPLICATIONS: Paracrine interactions of cancer stem cell populations impact therapeutic options and patient outcomes.
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Affiliation(s)
| | | | | | | | - Jianchun Wu
- University of Illinois Cancer Center, Chicago, Illinois
| | - David L Crowe
- University of Illinois Cancer Center, Chicago, Illinois.
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Arias-Salgado EG, Galvez E, Planas-Cerezales L, Pintado-Berninches L, Vallespin E, Martinez P, Carrillo J, Iarriccio L, Ruiz-Llobet A, Catalá A, Badell-Serra I, Gonzalez-Granado LI, Martín-Nalda A, Martínez-Gallo M, Galera-Miñarro A, Rodríguez-Vigil C, Bastos-Oreiro M, Perez de Nanclares G, Leiro-Fernández V, Uria ML, Diaz-Heredia C, Valenzuela C, Martín S, López-Muñiz B, Lapunzina P, Sevilla J, Molina-Molina M, Perona R, Sastre L. Genetic analyses of aplastic anemia and idiopathic pulmonary fibrosis patients with short telomeres, possible implication of DNA-repair genes. Orphanet J Rare Dis 2019; 14:82. [PMID: 30995915 PMCID: PMC6471801 DOI: 10.1186/s13023-019-1046-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/12/2019] [Indexed: 01/19/2023] Open
Abstract
Background Telomeres are nucleoprotein structures present at the terminal region of the chromosomes. Mutations in genes coding for proteins involved in telomere maintenance are causative of a number of disorders known as telomeropathies. The genetic origin of these diseases is heterogeneous and has not been determined for a significant proportion of patients. Methods This article describes the genetic characterization of a cohort of patients. Telomere length was determined by Southern blot and quantitative PCR. Nucleotide variants were analyzed either by high-resolution melting analysis and Sanger sequencing of selected exons or by massive sequencing of a panel of genes. Results Forty-seven patients with telomere length below the 10% of normal population, affected with three telomeropathies: dyskeratosis congenita (4), aplastic anemia (22) or pulmonary fibrosis (21) were analyzed. Eighteen of these patients presented known pathogenic or novel possibly pathogenic variants in the telomere-related genes TERT, TERC, RTEL1, CTC1 and ACD. In addition, the analyses of a panel of 188 genes related to haematological disorders indicated that a relevant proportion of the patients (up to 35%) presented rare variants in genes related to DNA repair or in genes coding for proteins involved in the resolution of complex DNA structures, that participate in telomere replication. Mutations in some of these genes are causative of several syndromes previously associated to telomere shortening. Conclusion Novel variants in telomere, DNA repair and replication genes are described that might indicate the contribution of variants in these genes to the development of telomeropathies. Patients carrying variants in telomere-related genes presented worse evolution after diagnosis than the rest of patients analyzed. Electronic supplementary material The online version of this article (10.1186/s13023-019-1046-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elena G Arias-Salgado
- Instituto de Investigaciones Biomedicas CSIC/UAM, IDIPaz, Arturo Duperier, 4, 28029, Madrid, Spain.,Advanced Medical Projects, Madrid, Spain
| | - Eva Galvez
- Hospital Niño Jesús, Hematología y Hemoterapia, Madrid, Spain
| | - Lurdes Planas-Cerezales
- ILD Unit Pneumology Department, University Hospital of Bellvitge, IDIBELL, University of Barcelona, Barcelona, Spain
| | - Laura Pintado-Berninches
- Instituto de Investigaciones Biomedicas CSIC/UAM, IDIPaz, Arturo Duperier, 4, 28029, Madrid, Spain.,Advanced Medical Projects, Madrid, Spain
| | - Elena Vallespin
- Institute of Medical and Molecular Genetics (INGEMM), Hospital Universitario La Paz, Madrid, Spain
| | - Pilar Martinez
- Institute of Medical and Molecular Genetics (INGEMM), Hospital Universitario La Paz, Madrid, Spain
| | - Jaime Carrillo
- Instituto de Investigaciones Biomedicas CSIC/UAM, IDIPaz, Arturo Duperier, 4, 28029, Madrid, Spain
| | - Laura Iarriccio
- Instituto de Investigaciones Biomedicas CSIC/UAM, IDIPaz, Arturo Duperier, 4, 28029, Madrid, Spain.,Advanced Medical Projects, Madrid, Spain
| | - Anna Ruiz-Llobet
- Pediatric Hematology and Oncology Department, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain.,Institut de Recerca Pediàtrica Hospital Sant Joan de Déu (IRP-HSJD), Esplugues de Llobregat, Barcelona, Spain
| | - Albert Catalá
- Pediatric Hematology and Oncology Department, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain.,Institut de Recerca Pediàtrica Hospital Sant Joan de Déu (IRP-HSJD), Esplugues de Llobregat, Barcelona, Spain
| | | | | | - Andrea Martín-Nalda
- Immunology Division, Pediatric Infectious Diseases and Immunodeficiencies Unit, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Spain
| | - Mónica Martínez-Gallo
- Immunology Division, Pediatric Infectious Diseases and Immunodeficiencies Unit, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Spain
| | | | | | | | - Guiomar Perez de Nanclares
- Molecular (Epi)Genetics Laboratory, BioAraba National Health Institute, OSI Araba University Hospital, Vitoria-Gasteiz, Spain
| | - Virginia Leiro-Fernández
- Pneumology Department, Hospital Álvaro Cunqueiro, Complexo Hospitalario Universitario de Vigo, NeumoVigoI+i Research Group, Vigo Biomedical Research Institute (IBIV), Barcelona, Spain
| | - Maria-Luz Uria
- Immunology Division, Pediatric Infectious Diseases and Immunodeficiencies Unit, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Spain
| | - Cristina Diaz-Heredia
- Immunology Division, Pediatric Infectious Diseases and Immunodeficiencies Unit, Hospital Universitari Vall d'Hebron (HUVH), Vall d'Hebron Research Institute (VHIR), Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Spain
| | | | - Sara Martín
- ILD Unit Pneumology Department, University Hospital of Bellvitge, IDIBELL, University of Barcelona, Barcelona, Spain
| | | | - Pablo Lapunzina
- Institute of Medical and Molecular Genetics (INGEMM), Hospital Universitario La Paz, Madrid, Spain.,CIBER de enfermedades raras (CIBERER), Madrid, Spain
| | - Julian Sevilla
- Hospital Niño Jesús, Hematología y Hemoterapia, Madrid, Spain.,CIBER de enfermedades raras (CIBERER), Madrid, Spain
| | - María Molina-Molina
- ILD Unit Pneumology Department, University Hospital of Bellvitge, IDIBELL, University of Barcelona, Barcelona, Spain.,CIBER of Respiratory diseases (CIBERES), Barcelona, Spain
| | - Rosario Perona
- Instituto de Investigaciones Biomedicas CSIC/UAM, IDIPaz, Arturo Duperier, 4, 28029, Madrid, Spain.,CIBER de enfermedades raras (CIBERER), Madrid, Spain
| | - Leandro Sastre
- Instituto de Investigaciones Biomedicas CSIC/UAM, IDIPaz, Arturo Duperier, 4, 28029, Madrid, Spain. .,CIBER de enfermedades raras (CIBERER), Madrid, Spain.
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50
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Özer Ö, Hickson ID. Pathways for maintenance of telomeres and common fragile sites during DNA replication stress. Open Biol 2019; 8:rsob.180018. [PMID: 29695617 PMCID: PMC5936717 DOI: 10.1098/rsob.180018] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 04/03/2018] [Indexed: 12/27/2022] Open
Abstract
Oncogene activation during tumour development leads to changes in the DNA replication programme that enhance DNA replication stress. Certain regions of the human genome, such as common fragile sites and telomeres, are particularly sensitive to DNA replication stress due to their inherently ‘difficult-to-replicate’ nature. Indeed, it appears that these regions sometimes fail to complete DNA replication within the period of interphase when cells are exposed to DNA replication stress. Under these conditions, cells use a salvage pathway, termed ‘mitotic DNA repair synthesis (MiDAS)’, to complete DNA synthesis in the early stages of mitosis. If MiDAS fails, the ensuing mitotic errors threaten genome integrity and cell viability. Recent studies have provided an insight into how MiDAS helps cells to counteract DNA replication stress. However, our understanding of the molecular mechanisms and regulation of MiDAS remain poorly defined. Here, we provide an overview of how DNA replication stress triggers MiDAS, with an emphasis on how common fragile sites and telomeres are maintained. Furthermore, we discuss how a better understanding of MiDAS might reveal novel strategies to target cancer cells that maintain viability in the face of chronic oncogene-induced DNA replication stress.
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Affiliation(s)
- Özgün Özer
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Ian D Hickson
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
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