1
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Neidle S. A Phenotypic Approach to the Discovery of Potent G-Quadruplex Targeted Drugs. Molecules 2024; 29:3653. [PMID: 39125057 PMCID: PMC11314571 DOI: 10.3390/molecules29153653] [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: 07/17/2024] [Revised: 07/29/2024] [Accepted: 07/30/2024] [Indexed: 08/12/2024] Open
Abstract
G-quadruplex (G4) sequences, which can fold into higher-order G4 structures, are abundant in the human genome and are over-represented in the promoter regions of many genes involved in human cancer initiation, progression, and metastasis. They are plausible targets for G4-binding small molecules, which would, in the case of promoter G4s, result in the transcriptional downregulation of these genes. However, structural information is currently available on only a very small number of G4s and their ligand complexes. This limitation, coupled with the currently restricted information on the G4-containing genes involved in most complex human cancers, has led to the development of a phenotypic-led approach to G4 ligand drug discovery. This approach was illustrated by the discovery of several generations of tri- and tetra-substituted naphthalene diimide (ND) ligands that were found to show potent growth inhibition in pancreatic cancer cell lines and are active in in vivo models for this hard-to-treat disease. The cycles of discovery have culminated in a highly potent tetra-substituted ND derivative, QN-302, which is currently being evaluated in a Phase 1 clinical trial. The major genes whose expression has been down-regulated by QN-302 are presented here: all contain G4 propensity and have been found to be up-regulated in human pancreatic cancer. Some of these genes are also upregulated in other human cancers, supporting the hypothesis that QN-302 is a pan-G4 drug of potential utility beyond pancreatic cancer.
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Affiliation(s)
- Stephen Neidle
- The School of Pharmacy, University College London, London WC1N 1AX, UK
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2
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Yan M, Zhang Z, Wang L, Huang H, Wang J, Zhu C, Li Z, Xu Z. Cross-talk of Three Molecular Subtypes of Telomere Maintenance Defines Clinical Characteristics and Tumor Microenvironment in Gastric Cancer. J Cancer 2024; 15:3227-3241. [PMID: 38706908 PMCID: PMC11064253 DOI: 10.7150/jca.92207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 03/27/2024] [Indexed: 05/07/2024] Open
Abstract
Background: Telomere maintenance takes part in the regulation of gastric cancer (GC) pathogenesis and is essential for patients' clinical features. Though the correlation between a single telomere maintenance-related gene and GC has previously been published, comprehensive exploration and systematic analysis remain to be studied. Our study is aimed at determining telomere maintenance-related molecular subtypes and examining their role in GC. Methods: By analyzing the transcriptome data, we identified three telomere maintenance-associated clusters (TMCs) with heterogeneity in clinical features and tumor microenvironment (TME). Then, we screened five prognostic telomere maintenance-related genes and established corresponding TM scores. Additionally, the expression level and biological function of tubulin beta 6 class V (TUBB6) were validated in GC tissues and cells. Results: TMC1 was correlated with EMT and TGF-beta pathway and predicted low tumor mutation burden (TMB) as well as bad prognostic outcomes. TMC3 was associated with cell cycle and DNA repair. In terms of TMB and overall survival, TMC3 exhibited opposite results against TMC1. Significant heterogeneity was observed between TMCs. TUBB6 was upregulated and could promote GC proliferation, migration, and invasion. Conclusion: Altogether, combining bioinformatics and functional experiments, we identified three molecular subtypes based on telomere maintenance-associated genes in GC, which could bring new ideas and novel biomarkers to the clinic.
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Affiliation(s)
- Mengpei Yan
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Zhijun Zhang
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Luyao Wang
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Hongxin Huang
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Jihuan Wang
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Chengjun Zhu
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Zheng Li
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
| | - Zekuan Xu
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu Province, China
- Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, Jiangsu Province, China
- The Institute of Gastric Cancer, Nanjing Medical University, Nanjing, Jiangsu Province, China
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3
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Prasad R, Kaur G. Recent Domains in Telomere and Telomerase Targeting for Accomplished Cancer Therapy. Indian J Clin Biochem 2024; 39:151-153. [PMID: 38577142 PMCID: PMC10987445 DOI: 10.1007/s12291-024-01211-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Affiliation(s)
- Rajendra Prasad
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Gurjit Kaur
- Department of Physiology, Government Medical College and Hospital, Sector 32, Chandigarh, India
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4
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Ali JH, Walter M. Combining old and new concepts in targeting telomerase for cancer therapy: transient, immediate, complete and combinatory attack (TICCA). Cancer Cell Int 2023; 23:197. [PMID: 37679807 PMCID: PMC10483736 DOI: 10.1186/s12935-023-03041-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 08/25/2023] [Indexed: 09/09/2023] Open
Abstract
Telomerase can overcome replicative senescence by elongation of telomeres but is also a specific element in most cancer cells. It is expressed more vastly than any other tumor marker. Telomerase as a tumor target inducing replicative immortality can be overcome by only one other mechanism: alternative lengthening of telomeres (ALT). This limits the probability to develop resistance to treatments. Moreover, telomerase inhibition offers some degree of specificity with a low risk of toxicity in normal cells. Nevertheless, only one telomerase antagonist reached late preclinical studies. The underlying causes, the pitfalls of telomerase-based therapies, and future chances based on recent technical advancements are summarized in this review. Based on new findings and approaches, we propose a concept how long-term survival in telomerase-based cancer therapies can be significantly improved: the TICCA (Transient Immediate Complete and Combinatory Attack) strategy.
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Affiliation(s)
- Jaber Haj Ali
- Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
- Institute of Clinical Chemistry and Laboratory Medicine, Universitätsmedizin Rostock, Ernst-Heydemann-Straße 6, 18057, Rostock, Germany
| | - Michael Walter
- Institute of Clinical Chemistry and Laboratory Medicine, Universitätsmedizin Rostock, Ernst-Heydemann-Straße 6, 18057, Rostock, Germany.
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5
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Gao J, Pickett HA. Targeting telomeres: advances in telomere maintenance mechanism-specific cancer therapies. Nat Rev Cancer 2022; 22:515-532. [PMID: 35790854 DOI: 10.1038/s41568-022-00490-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/25/2022] [Indexed: 12/31/2022]
Abstract
Cancer cells establish replicative immortality by activating a telomere-maintenance mechanism (TMM), be it telomerase or the alternative lengthening of telomeres (ALT) pathway. Targeting telomere maintenance represents an intriguing opportunity to treat the vast majority of all cancer types. Whilst telomerase inhibitors have historically been heralded as promising anticancer agents, the reality has been more challenging, and there are currently no therapeutic options for cancer types that use ALT despite their aggressive nature and poor prognosis. In this Review, we discuss the mechanistic differences between telomere maintenance by telomerase and ALT, the current methods used to detect each mechanism, the utility of these tests for clinical diagnosis, and recent developments in the therapeutic strategies being employed to target both telomerase and ALT. We present notable developments in repurposing established therapeutic agents and new avenues that are emerging to target cancer types according to which TMM they employ. These opportunities extend beyond inhibition of telomere maintenance, by finding and exploiting inherent weaknesses in the telomeres themselves to trigger rapid cellular effects that lead to cell death.
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Affiliation(s)
- Jixuan Gao
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW, Australia
| | - Hilda A Pickett
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW, Australia.
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6
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Hirsch AG, Becker D, Lamping JP, Krebber H. Unraveling the stepwise maturation of the yeast telomerase including a Cse1 and Mtr10 mediated quality control checkpoint. Sci Rep 2021; 11:22174. [PMID: 34773052 PMCID: PMC8590012 DOI: 10.1038/s41598-021-01599-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 10/29/2021] [Indexed: 01/17/2023] Open
Abstract
Telomerases elongate the ends of chromosomes required for cell immortality through their reverse transcriptase activity. By using the model organism Saccharomyces cerevisiae we defined the order in which the holoenzyme matures. First, a longer precursor of the telomerase RNA, TLC1 is transcribed and exported into the cytoplasm, where it associates with the protecting Sm-ring, the Est and the Pop proteins. This partly matured telomerase is re-imported into the nucleus via Mtr10 and a novel TLC1-import factor, the karyopherin Cse1. Remarkably, while mutations in all known transport factors result in short telomere ends, mutation in CSE1 leads to the amplification of Y′ elements in the terminal chromosome regions and thus elongated telomere ends. Cse1 does not only support TLC1 import, but also the Sm-ring stabilization on the RNA enableling Mtr10 contact and nuclear import. Thus, Sm-ring formation and import factor contact resembles a quality control step in the maturation process of the telomerase. The re-imported immature TLC1 is finally trimmed into the 1158 nucleotides long mature form via the nuclear exosome. TMG-capping of TLC1 finalizes maturation, leading to mature telomerase.
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Affiliation(s)
- Anna Greta Hirsch
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie Und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany
| | - Daniel Becker
- Philipps-Universität Marburg, Klinik für Dermatologie Und Allergologie, Baldingerstraße, 35043, Marburg, Germany
| | - Jan-Philipp Lamping
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie Und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany
| | - Heike Krebber
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie Und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany.
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7
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Chen L, Roake CM, Galati A, Bavasso F, Micheli E, Saggio I, Schoeftner S, Cacchione S, Gatti M, Artandi SE, Raffa GD. Loss of Human TGS1 Hypermethylase Promotes Increased Telomerase RNA and Telomere Elongation. Cell Rep 2021; 30:1358-1372.e5. [PMID: 32023455 PMCID: PMC7156301 DOI: 10.1016/j.celrep.2020.01.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 11/09/2019] [Accepted: 12/31/2019] [Indexed: 02/08/2023] Open
Abstract
Biogenesis of the human telomerase RNA (hTR) involves a complex series of posttranscriptional modifications, including hypermethylation of the 5' mono-methylguanosine cap to a tri-methylguanosine cap (TMG). How the TMG cap affects hTR maturation is unknown. Here, we show that depletion of trimethylguanosine synthase 1 (TGS1), the enzyme responsible for cap hypermethylation, increases levels of hTR and telomerase. Diminished trimethylation increases hTR association with the cap-binding complex (CBC) and with Sm chaperone proteins. Loss of TGS1 causes an increase in accumulation of mature hTR in both the nucleus and the cytoplasm compared with controls. In TGS1 mutant cells, increased hTR assembles with telomerase reverse transcriptase (TERT) protein to yield elevated active telomerase complexes and increased telomerase activity, resulting in telomere elongation in cultured human cells. Our results show that TGS1-mediated hypermethylation of the hTR cap inhibits hTR accumulation, restrains levels of assembled telomerase, and limits telomere elongation.
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Affiliation(s)
- Lu Chen
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Caitlin M Roake
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alessandra Galati
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy
| | - Francesca Bavasso
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy
| | - Emanuela Micheli
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy
| | - Isabella Saggio
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy
| | - Stefan Schoeftner
- Cancer Epigenetic Group, Laboratorio Nazionale Consorzio Interuniversitario Biotecnologie, Trieste, Italy
| | - Stefano Cacchione
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy
| | - Maurizio Gatti
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy; Istituto di Biologia e Patologia Molecolari (IBPM) del CNR, Roma, Italy
| | - Steven E Artandi
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Grazia D Raffa
- Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Roma, Italy.
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8
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Akincilar SC, Chan CHT, Ng QF, Fidan K, Tergaonkar V. Non-canonical roles of canonical telomere binding proteins in cancers. Cell Mol Life Sci 2021; 78:4235-4257. [PMID: 33599797 PMCID: PMC8164586 DOI: 10.1007/s00018-021-03783-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 12/28/2020] [Accepted: 01/29/2021] [Indexed: 02/06/2023]
Abstract
Reactivation of telomerase is a major hallmark observed in 90% of all cancers. Yet paradoxically, enhanced telomerase activity does not correlate with telomere length and cancers often possess short telomeres; suggestive of supplementary non-canonical roles that telomerase might play in the development of cancer. Moreover, studies have shown that aberrant expression of shelterin proteins coupled with their release from shortening telomeres can further promote cancer by mechanisms independent of their telomeric role. While targeting telomerase activity appears to be an attractive therapeutic option, this approach has failed in clinical trials due to undesirable cytotoxic effects on stem cells. To circumvent this concern, an alternative strategy could be to target the molecules involved in the non-canonical functions of telomeric proteins. In this review, we will focus on emerging evidence that has demonstrated the non-canonical roles of telomeric proteins and their impact on tumorigenesis. Furthermore, we aim to address current knowledge gaps in telomeric protein functions and propose future research approaches that can be undertaken to achieve this.
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Affiliation(s)
- Semih Can Akincilar
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore
| | - Claire Hian Tzer Chan
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore
| | - Qin Feng Ng
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore
| | - Kerem Fidan
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore
| | - Vinay Tergaonkar
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore.
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117593, Singapore.
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9
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Kamal S, Junaid M, Ejaz A, Bibi I, Akash MSH, Rehman K. The secrets of telomerase: Retrospective analysis and future prospects. Life Sci 2020; 257:118115. [PMID: 32698073 DOI: 10.1016/j.lfs.2020.118115] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/06/2020] [Accepted: 07/13/2020] [Indexed: 12/12/2022]
Abstract
Telomerase plays a significant role to maintain and regulate the telomere length, cellular immortality and senescence by the addition of guanine-rich repetitive sequences. Chronic inflammation or oxidative stress-induced infection downregulates TERT gene modifying telomerase activity thus contributing to the early steps of gastric carcinogenesis process. Furthermore, telomere-telomerase system performs fundamental role in the pathogenesis and progression of diabetes mellitus as well as in its vascular intricacy. The cessation of cell proliferation in cultured cells by inhibiting the telomerase activity of transformed cells renders the rationale for culling of telomerase as a target therapy for the treatment of metabolic disorders and various types of cancers. In this article, we have briefly described the role of immune system and malignant cells in the expression of telomerase with critical analysis on the gaps and potential for future studies. The key findings regarding the secrets of the telomerase summarized in this article will help in future treatment modalities for the prevention of various types of cancers and metabolic disorders notably diabetes mellitus.
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Affiliation(s)
- Shagufta Kamal
- Department of Biochemistry, Government College University Faisalabad, Pakistan
| | - Muhammad Junaid
- Department of Biochemistry, Government College University Faisalabad, Pakistan
| | - Arslan Ejaz
- Department of Biochemistry, Government College University Faisalabad, Pakistan
| | - Ismat Bibi
- Department of Chemistry, Islamia University, Bahawalpur, Pakistan
| | | | - Kanwal Rehman
- Department of Pharmacy, University of Agriculture, Faisalabad, Pakistan.
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10
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Berrino E, Angeli A, Zhdanov DD, Kiryukhina AP, Milaneschi A, De Luca A, Bozdag M, Carradori S, Selleri S, Bartolucci G, Peat TS, Ferraroni M, Supuran CT, Carta F. Azidothymidine "Clicked" into 1,2,3-Triazoles: First Report on Carbonic Anhydrase-Telomerase Dual-Hybrid Inhibitors. J Med Chem 2020; 63:7392-7409. [PMID: 32463228 PMCID: PMC8154556 DOI: 10.1021/acs.jmedchem.0c00636] [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] [Indexed: 12/11/2022]
Abstract
![]()
Cancer cells rely on the enzyme telomerase
(EC 2.7.7.49) to promote
cellular immortality. Telomerase inhibitors (i.e., azidothymidine)
can represent promising antitumor agents, although showing high toxicity
when administered alone. Better outcomes were observed within a multipharmacological
approach instead. In this context, we exploited the validated antitumor
targets carbonic anhydrases (CAs; EC 4.2.1.1) IX and XII to attain
the first proof of concept on CA–telomerase dual-hybrid inhibitors.
Compounds 1b, 7b, 8b, and 11b showed good in vitro
inhibition potency against the CAs IX and XII, with KI values in the low nanomolar range, and strong antitelomerase
activity in PC-3 and HT-29 cells (IC50 values ranging from
5.2 to 9.1 μM). High-resolution X-ray crystallography on selected
derivatives in the adduct with hCA II as a model study allowed to
determine their binding modes and thus to set the structural determinants
necessary for further development of compounds selectively targeting
the tumoral cells.
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Affiliation(s)
- Emanuela Berrino
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Andrea Angeli
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Dmitry D Zhdanov
- Institute of Biomedical Chemistry, Pogodinskaya st. 10/8, 119121 Moscow, Russia.,Peoples Friendship University of Russia (RUDN University), Miklukho-Maklaya st. 6, 117198 Moscow, Russia
| | - Anna P Kiryukhina
- Institute of Biomedical Chemistry, Pogodinskaya st. 10/8, 119121 Moscow, Russia
| | - Andrea Milaneschi
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Alessandro De Luca
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Murat Bozdag
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Simone Carradori
- Department of Pharmacy, "G. d'Annunzio" University of Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy
| | - Silvia Selleri
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Gianluca Bartolucci
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Thomas S Peat
- CSIRO, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Marta Ferraroni
- Dipartimento di Chimica "Ugo Schiff", Università di Firenze, Via della Lastruccia 3-13, 50019 Sesto Fiorentino (Florence), Italy
| | - Claudiu T Supuran
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Fabrizio Carta
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
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11
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Bhattacharjee P, Das A, Giri AK, Bhattacharjee P. Epigenetic regulations in alternative telomere lengthening: Understanding the mechanistic insight in arsenic-induced skin cancer patients. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 704:135388. [PMID: 31837846 DOI: 10.1016/j.scitotenv.2019.135388] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 11/01/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
Telomere integrity is considered to be one of the primary mechanisms during malignant transformation. Arsenic, a group 1 carcinogenic metalloid, has been reported to cause telomere lengthening in a telomerase-independent manner. Recent studies suggest a significant role for epigenetic modifications in regulating telomeric length and integrity. Here, we have explored the role of epigenetic deregulation in alternative lengthening of telomeres (ALT) in arsenic-exposed skin cancer tissues and corresponding non-tumor tissues. The relative telomere length (RTL) was analyzed by qRT-PCR using 2-ΔΔCt method. The subtelomeric methylation pattern of the four chromosomes (7q, 18p, 21q and XpYp) were analysed by Methylation Specific PCR (MSP) in 40 pairs of arsenic exposed skin cancer tissues and its corresponding control. The role of constitutive heterochromatin histone marks in the regulation of telomere length (TL) was analyzed by targeted ELISA. A 2-fold increase of relative telomere length in 85% of the arsenic-induced skin cancer tissues was observed. Among the four chromosomes, subtelomere of XpYp was found to be hypermethylated (p < 0.001) whereas 18p was hypomethylated (p < 0.01). Additionally, the level of H4K20me3, a heterochromatic mark was found to be significantly down-regulated (p < 0.0003), and inversely correlated with telomere length indicating loss of heterochromatinization of telomeric DNA. These observations highlight the novel role of epigenetic regulation in the maintenance of constitutive heterochromatin structure at telomere. Alteration in subtelomeric DNA methylation patterns and depletion of H4K20me3 might lead to loss of heterochromatinization resulting in arsenic-induced telomeric elongation. We provide novel data indicating possible alternative determinants of telomere elongation through epigenetic modifications during arsenic-induced skin carcinogenesis which could be used as early 'epimarkers' in the near future. The findings provide new insights about the mechanism of arsenic-induced carcinogenesis.
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Affiliation(s)
- Pritha Bhattacharjee
- Department of Zoology, University of Calcutta, Kolkata 700019, India; Department of Environmental Science, University of Calcutta, Kolkata 700019, India
| | - Ankita Das
- Department of Environmental Science, University of Calcutta, Kolkata 700019, India
| | - Ashok K Giri
- Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Pritha Bhattacharjee
- Department of Environmental Science, University of Calcutta, Kolkata 700019, India.
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12
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Li W, Mjekiqi E, Douma W, Wang X, Kavatsyuk O, Hoekstra R, Poully J, Schlathölter T. Hole Migration in Telomere-Based Oligonucleotide Anions and G-Quadruplexes. Chemistry 2019; 25:16114-16119. [PMID: 31614016 PMCID: PMC6972685 DOI: 10.1002/chem.201904105] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/11/2019] [Indexed: 01/24/2023]
Abstract
Vacuum ultraviolet photoionization of a gas-phase oligonucleotide anion leads to the formation of a valence hole. This hole migrates towards an energetically favorable site where it can weaken bonds and ultimately lead to bond cleavage. We have studied Vacuum UV photoionization of deprotonated oligonucleotides containing the human telomere sequence dTTAGGG and G-quadruplex structures consisting of four dTGGGGT single strands, stabilized by NH4 + counter ions. The oligonucleotide and G-quadruplex anions were confined in a radiofrequency ion trap, interfaced with a synchrotron beamline and the photofragmentation was studied using time-of-flight mass spectrometry. Oligonucleotide 12-mers containing the 5'-TTAGGG sequence were found to predominantly break in the GGG region, whereas no selective bond cleavage region was observed for the reversed 5'-GGGATT sequence. For G-quadruplex structures, fragmentation was quenched and mostly non-dissociative single and double electron removal was observed.
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Affiliation(s)
- Wen Li
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747AGGroningenThe Netherlands
| | - Edita Mjekiqi
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747AGGroningenThe Netherlands
| | - Wessel Douma
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747AGGroningenThe Netherlands
| | - Xin Wang
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747AGGroningenThe Netherlands
| | - Oksana Kavatsyuk
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747AGGroningenThe Netherlands
- University College GroningenUniversity of GroningenHoendiepskade 23/249718 BGGroningenThe Netherlands
| | - Ronnie Hoekstra
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747AGGroningenThe Netherlands
| | - Jean‐Christophe Poully
- CIMAP laboratory UMR 6252Université de Caen Normandie/CEA/CNRS/ENSICAENBd Becquerel14070CAEN Cedex 5France
| | - Thomas Schlathölter
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747AGGroningenThe Netherlands
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López-Alcorocho JM, Guillén-Vicente I, Rodríguez-Iñigo E, Guillén-Vicente M, Fernández-Jaén TF, Caballero R, Casqueiro M, Najarro P, Abelow S, Guillén-García P. Study of Telomere Length in Preimplanted Cultured Chondrocytes. Cartilage 2019; 10:36-42. [PMID: 29322876 PMCID: PMC6376562 DOI: 10.1177/1947603517749918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
DESIGN In the process of cell division, the extremes of the eukaryotic chromosomes are progressively shortening, and this phenomenon is related to cell degeneration and senescence. The treatment of cartilage lesions with autologous chondrocytes implies that cells proliferate in an artificial environment. We have studied the viability of cultured chondrocytes after measurement of their telomere length before implantation. METHODS Articular cartilage biopsies (B1, B2, and B3) were obtained from 3 patients (2 males and 1 female) with knee cartilage defects, who were going to be treated with chondrocyte implantation. Chondrocytes were cultured in DMEM with autologous serum. After the third passage, an aliquot of 1 million cells was removed to estimate the telomere length and the remaining cells were implanted. Telomere length was measured by quantitative fluorescent in situ hybridization (Q-FISH). Patients' clinical outcome was determined preoperatively, and 12 and 24 months postimplantation with the International Knee Documentation Committee (IKDC) questionnaire. RESULTS After chondrocyte implantation, IKDC score doubled at 12 and 24 months with regard to the basal value. After 3 passages, chondrocytes were cultured for a mean of 45.67 days, the mean duplication time being 4.53 days and the mean number of cell divisions being 10.04 during the culture period. The 20th percentile of telomere lengths were 6.84, 6.96, and 7.06 kbp and the median telomere lengths 10.30, 10.47, and 10.73 kbp, respectively. No significant correlation was found between IKDC score and telomere length. CONCLUSION Culturing autologous chondrocytes for implantation is not related to cell senescence in terms of telomere length.
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Affiliation(s)
- Juan Manuel López-Alcorocho
- Research Unit, Clínica Cemtro, Madrid, Spain,Juan Manuel López-Alcorocho, Research Unit, Clínica Cemtro, C/ Ventisquero de la Condesa, 42, 28035 Madrid, Spain.
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Abstract
Studies of rare and common illnesses have led to remarkable progress in the understanding of the role of telomeres (nucleoprotein complexes at chromosome ends essential for chromosomal integrity) in human disease. Telomere biology disorders encompass a growing spectrum of conditions caused by rare pathogenic germline variants in genes encoding essential aspects of telomere function. Dyskeratosis congenita, a disorder at the severe end of this spectrum, typically presents in childhood with the classic triad of abnormal skin pigmentation, nail dystrophy, and oral leukoplakia, accompanied by a very high risk of bone marrow failure, cancer, pulmonary fibrosis, and other medical problems. In contrast, the less severe end of the telomere biology disorder spectrum consists of middle-age or older adults with just one feature typically seen in dyskeratosis congenita, such as pulmonary fibrosis or bone marrow failure. In the common disease realm, large-scale molecular epidemiology studies have discovered novel associations between illnesses, such as cancer, heart disease, and mental health, and both telomere length and common genetic variants in telomere biology genes. This review highlights recent findings of telomere biology in human disease from both the rare and common disease perspectives. Multi-disciplinary collaborations between clinicians, basic scientists, and epidemiologist are essential as we seek to incorporate new telomere biology discoveries to improve health outcomes.
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Affiliation(s)
- Sharon A. Savage
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, USA
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16
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Lv N, Sun M, Liu C, Li J. Design and synthesis of 2-phenylpyrimidine coumarin derivatives as anticancer agents. Bioorg Med Chem Lett 2017; 27:4578-4581. [DOI: 10.1016/j.bmcl.2017.08.044] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 08/17/2017] [Accepted: 08/19/2017] [Indexed: 12/12/2022]
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Abstract
Aberrations in telomere biology are among the earliest events in prostate cancer tumorigenesis and continue during tumour progression. Substantial telomere shortening occurs in prostate cancer cells and high-grade prostatic intraepithelial neoplasia. Not all mechanisms of telomere shortening are understood, but oxidative stress from local inflammation might accelerate prostatic telomere loss. Critically short telomeres can drive the accumulation of tumour-promoting genomic alterations; however, continued telomere erosion is unsustainable and must be mitigated to ensure cancer cell survival and unlimited replication potential. Prostate cancers predominantly maintain telomeres by activating telomerase, but alternative mechanisms of telomere extension can occur in metastatic disease. Telomerase activity and telomere length assessment might be useful in prostate cancer diagnosis and prognosis. Telomere shortening in normal stromal cells has been associated with prostate cancer, whereas variable telomere lengths in prostate cancer cells and telomere shortening in cancer-associated stromal cells correlated with lethal disease. Single-agent telomerase-targeted treatments for solid cancers were ineffective in clinical trials but have not been investigated in prostate cancer and might be useful in combination with established regimens. Telomere-directed strategies have not been explored as extensively. Telomere deprotection strategies have the advantage of being effective in both telomerase-dependent and telomerase-independent cancers. Disruption of androgen receptor function in prostate cancer cells results in telomere dysfunction, indicating telomeres and telomerase as potential therapeutic targets in prostate cancer.
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Naderlinger E, Holzmann K. Epigenetic Regulation of Telomere Maintenance for Therapeutic Interventions in Gliomas. Genes (Basel) 2017; 8:E145. [PMID: 28513547 PMCID: PMC5448019 DOI: 10.3390/genes8050145] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/08/2017] [Accepted: 05/12/2017] [Indexed: 02/07/2023] Open
Abstract
High-grade astrocytoma of WHO grade 4 termed glioblastoma multiforme (GBM) is a common human brain tumor with poor patient outcome. Astrocytoma demonstrates two known telomere maintenance mechanisms (TMMs) based on telomerase activity (TA) and on alternative lengthening of telomeres (ALT). ALT is associated with lower tumor grades and better outcome. In contrast to ALT, regulation of TA in tumors by direct mutation and epigenetic activation of the hTERT promoter is well established. Here, we summarize the genetic background of TMMs in non-malignant cells and in cancer, in addition to clinical and pathological features of gliomas. Furthermore, we present new evidence for epigenetic mechanisms (EMs) involved in regulation of ALT and TA with special emphasis on human diffuse gliomas as potential therapeutic drug targets. We discuss the role of TMM associated telomeric chromatin factors such as DNA and histone modifying enzymes and non-coding RNAs including microRNAs and long telomeric TERRA transcripts.
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Affiliation(s)
- Elisabeth Naderlinger
- Institute of Cancer Research, Comprehensive Cancer Center, Medical University of Vienna, Borschkegasse 8a, Vienna 1090, Austria.
| | - Klaus Holzmann
- Institute of Cancer Research, Comprehensive Cancer Center, Medical University of Vienna, Borschkegasse 8a, Vienna 1090, Austria.
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Lloyd NR, Dickey TH, Hom RA, Wuttke DS. Tying up the Ends: Plasticity in the Recognition of Single-Stranded DNA at Telomeres. Biochemistry 2016; 55:5326-40. [PMID: 27575340 PMCID: PMC5656232 DOI: 10.1021/acs.biochem.6b00496] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Telomeres terminate nearly exclusively in single-stranded DNA (ssDNA) overhangs comprised of the G-rich 3' end. This overhang varies widely in length from species to species, ranging from just a few bases to several hundred nucleotides. These overhangs are not merely a remnant of DNA replication but rather are the result of complex further processing. Proper management of the telomeric overhang is required both to deter the action of the DNA damage machinery and to present the ends properly to the replicative enzyme telomerase. This Current Topic addresses the biochemical and structural features used by the proteins that manage these variable telomeric overhangs. The Pot1 protein tightly binds the single-stranded overhang, preventing DNA damage sensors from binding. Pot1 also orchestrates the access of telomerase to that same substrate. The remarkable plasticity of the binding interface exhibited by the Schizosaccharomyces pombe Pot1 provides mechanistic insight into how these roles may be accomplished, and disease-associated mutations clustered around the DNA-binding interface in the hPOT1 highlight the importance of this function. The budding yeast Cdc13-Stn1-Ten1, a telomeric RPA complex closely associated with telomere function, also interacts with ssDNA in a fashion that allows degenerate sequences to be recognized. A related human complex composed of hCTC1, hSTN1, and hTEN1 has recently emerged with links to both telomere maintenance and general DNA replication and also exhibits mutations associated with telomere pathologies. Overall, these sequence-specific ssDNA binders exhibit a range of recognition properties that allow them to perform their unique biological functions.
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Affiliation(s)
- Neil R. Lloyd
- Department of Chemistry and Biochemistry, 596 UCB, University of Colorado Boulder, Boulder, CO 80309-0596, USADepartment of Chemistry and Biochemistry, 596 UCB, University of Colorado Boulder, Boulder, CO 80309, USA
| | | | - Robert A. Hom
- Department of Chemistry and Biochemistry, 596 UCB, University of Colorado Boulder, Boulder, CO 80309-0596, USADepartment of Chemistry and Biochemistry, 596 UCB, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Deborah S. Wuttke
- Department of Chemistry and Biochemistry, 596 UCB, University of Colorado Boulder, Boulder, CO 80309-0596, USADepartment of Chemistry and Biochemistry, 596 UCB, University of Colorado Boulder, Boulder, CO 80309, USA
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Jäger K, Walter M. Therapeutic Targeting of Telomerase. Genes (Basel) 2016; 7:genes7070039. [PMID: 27455328 PMCID: PMC4962009 DOI: 10.3390/genes7070039] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 06/16/2016] [Accepted: 06/24/2016] [Indexed: 12/20/2022] Open
Abstract
Telomere length and cell function can be preserved by the human reverse transcriptase telomerase (hTERT), which synthesizes the new telomeric DNA from a RNA template, but is normally restricted to cells needing a high proliferative capacity, such as stem cells. Consequently, telomerase-based therapies to elongate short telomeres are developed, some of which have successfully reached the stage I in clinical trials. Telomerase is also permissive for tumorigenesis and 90% of all malignant tumors use telomerase to obtain immortality. Thus, reversal of telomerase upregulation in tumor cells is a potential strategy to treat cancer. Natural and small-molecule telomerase inhibitors, immunotherapeutic approaches, oligonucleotide inhibitors, and telomerase-directed gene therapy are useful treatment strategies. Telomerase is more widely expressed than any other tumor marker. The low expression in normal tissues, together with the longer telomeres in normal stem cells versus cancer cells, provides some degree of specificity with low risk of toxicity. However, long term telomerase inhibition may elicit negative effects in highly-proliferative cells which need telomerase for survival, and it may interfere with telomere-independent physiological functions. Moreover, only a few hTERT molecules are required to overcome senescence in cancer cells, and telomerase inhibition requires proliferating cells over a sufficient number of population doublings to induce tumor suppressive senescence. These limitations may explain the moderate success rates in many clinical studies. Despite extensive studies, only one vaccine and one telomerase antagonist are routinely used in clinical work. For complete eradication of all subpopulations of cancer cells a simultaneous targeting of several mechanisms will likely be needed. Possible technical improvements have been proposed including the development of more specific inhibitors, methods to increase the efficacy of vaccination methods, and personalized approaches. Telomerase activation and cell rejuvenation is successfully used in regenerative medicine for tissue engineering and reconstructive surgery. However, there are also a number of pitfalls in the treatment with telomerase activating procedures for the whole organism and for longer periods of time. Extended cell lifespan may accumulate rare genetic and epigenetic aberrations that can contribute to malignant transformation. Therefore, novel vector systems have been developed for a 'mild' integration of telomerase into the host genome and loss of the vector in rapidly-proliferating cells. It is currently unclear if this technique can also be used in human beings to treat chronic diseases, such as atherosclerosis.
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Affiliation(s)
- Kathrin Jäger
- Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin 13353, Germany.
| | - Michael Walter
- Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin 13353, Germany.
- Labor Berlin-Charité Vivantes Services GmbH, Sylter Str. 2, Berlin 13353, Germany.
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Abstract
The addition of telomeric DNA to chromosome ends is an essential cellular activity that compensates for the loss of genomic DNA that is due to the inability of the conventional DNA replication apparatus to duplicate the entire chromosome. The telomerase reverse transcriptase and its associated RNA bind to the very end of the telomere via a sequence in the RNA and specific protein-protein interactions. Telomerase RNA also provides the template for addition of new telomeric repeats by the reverse-transcriptase protein subunit. In addition to the template, there are 3 other conserved regions in telomerase RNA that are essential for normal telomerase activity. Here we briefly review the conserved core regions of telomerase RNA and then focus on a recent study in fission yeast that determined the function of another conserved region in telomerase RNA called the Stem Terminus Element (STE). (1) The STE is distant from the templating core of telomerase in both the linear and RNA secondary structure, but, nonetheless, affects the fidelity of telomere sequence addition and, in turn, the ability of telomere binding proteins to bind and protect chromosome ends. We will discuss possible mechanisms of STE action and the suitability of the STE as an anti-cancer target.
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Affiliation(s)
- Christopher J Webb
- a Department of Molecular Biology , Princeton University , Princeton , NJ , USA
| | - Virginia A Zakian
- a Department of Molecular Biology , Princeton University , Princeton , NJ , USA
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