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Kumar N, Sethi G. Telomerase and hallmarks of cancer: An intricate interplay governing cancer cell evolution. Cancer Lett 2023; 578:216459. [PMID: 37863351 DOI: 10.1016/j.canlet.2023.216459] [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: 08/21/2023] [Revised: 10/02/2023] [Accepted: 10/17/2023] [Indexed: 10/22/2023]
Abstract
Transformed cells must acquire specific characteristics to be malignant. Weinberg and Hanahan characterize these characteristics as cancer hallmarks. Though these features are independently driven, substantial signaling crosstalk in transformed cells efficiently promotes these feature acquisitions. Telomerase is an enzyme complex that maintains telomere length. However, its main component, Telomere reverse transcriptase (TERT), has been found to interact with various signaling molecules like cMYC, NF-kB, BRG1 and cooperate in transcription and metabolic reprogramming, acting as a strong proponent of malignant features such as cell death resistance, sustained proliferation, angiogenesis activation, and metastasis, among others. It allows cells to avoid replicative senescence and achieve endless replicative potential. This review summarizes both the canonical and noncanonical functions of TERT and discusses how they promote cancer hallmarks. Understanding the role of Telomerase in promoting cancer hallmarks provides vital insight into the underlying mechanism of cancer genesis and progression and telomerase intervention as a possible therapeutic target for cancer treatment. More investigation into the precise molecular mechanisms of telomerase-mediated impacts on cancer hallmarks will contribute to developing more focused and customized cancer treatment methods.
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Affiliation(s)
- Naveen Kumar
- Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore, 138673, Singapore
| | - Gautam Sethi
- Department of Pharmacology and NUS Centre for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117600, Singapore.
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2
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Kim JJ, Ahn A, Ying J, Hickman E, Ludlow AT. Exercise as a Therapy to Maintain Telomere Function and Prevent Cellular Senescence. Exerc Sport Sci Rev 2023; 51:150-160. [PMID: 37288975 PMCID: PMC10526708 DOI: 10.1249/jes.0000000000000324] [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] [Indexed: 06/09/2023]
Abstract
Exercise transiently impacts the expression, regulation, and activity of TERT/telomerase to maintain telomeres and protect the genome from insults. By protecting the telomeres (chromosome ends) and the genome, telomerase promotes cellular survival and prevents cellular senescence. By increasing cellular resiliency, via the actions of telomerase and TERT, exercise promotes healthy aging.
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Affiliation(s)
- Jeongjin J Kim
- School of Kinesiology, University of Michigan, Ann Arbor, MI
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3
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Kim JJ, Sayed ME, Ahn A, Slusher AL, Ying JY, Ludlow AT. Dynamics of TERT regulation via alternative splicing in stem cells and cancer cells. PLoS One 2023; 18:e0289327. [PMID: 37531400 PMCID: PMC10395990 DOI: 10.1371/journal.pone.0289327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/17/2023] [Indexed: 08/04/2023] Open
Abstract
Part of the regulation of telomerase activity includes the alternative splicing (AS) of the catalytic subunit telomerase reverse transcriptase (TERT). Although a therapeutic window for telomerase/TERT inhibition exists between cancer cells and somatic cells, stem cells express TERT and rely on telomerase activity for physiological replacement of cells. Therefore, identifying differences in TERT regulation between stem cells and cancer cells is essential for developing telomerase inhibition-based cancer therapies that reduce damage to stem cells. In this study, we measured TERT splice variant expression and telomerase activity in induced pluripotent stem cells (iPSCs), neural progenitor cells (NPCs), and non-small cell lung cancer cells (NSCLC, Calu-6 cells). We observed that a NOVA1-PTBP1-PTBP2 axis regulates TERT alternative splicing (AS) in iPSCs and their differentiation into NPCs. We also found that splice-switching of TERT, which regulates telomerase activity, is induced by different cell densities in stem cells but not cancer cells. Lastly, we identified cell type-specific splicing factors that regulate TERT AS. Overall, our findings represent an important step forward in understanding the regulation of TERT AS in stem cells and cancer cells.
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Affiliation(s)
- Jeongjin J Kim
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Mohammed E Sayed
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Alexander Ahn
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Aaron L Slusher
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jeffrey Y Ying
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Andrew T Ludlow
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
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4
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Booth LK, Redgrave RE, Tual-Chalot S, Spyridopoulos I, Phillips HM, Richardson GD. Heart Disease and Ageing: The Roles of Senescence, Mitochondria, and Telomerase in Cardiovascular Disease. Subcell Biochem 2023; 103:45-78. [PMID: 37120464 DOI: 10.1007/978-3-031-26576-1_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
During ageing molecular damage leads to the accumulation of several hallmarks of ageing including mitochondrial dysfunction, cellular senescence, genetic instability and chronic inflammation, which contribute to the development and progression of ageing-associated diseases including cardiovascular disease. Consequently, understanding how these hallmarks of biological ageing interact with the cardiovascular system and each other is fundamental to the pursuit of improving cardiovascular health globally. This review provides an overview of our current understanding of how candidate hallmarks contribute to cardiovascular diseases such as atherosclerosis, coronary artery disease and subsequent myocardial infarction, and age-related heart failure. Further, we consider the evidence that, even in the absence of chronological age, acute cellular stress leading to accelerated biological ageing expedites cardiovascular dysfunction and impacts on cardiovascular health. Finally, we consider the opportunities that modulating hallmarks of ageing offer for the development of novel cardiovascular therapeutics.
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Affiliation(s)
- Laura K Booth
- Translational and Clinical Research Institute, Vascular Biology and Medicine Theme, Newcastle University, Newcastle upon Tyne, UK
| | - Rachael E Redgrave
- Biosciences Institute, Vascular Biology and Medicine Theme, Newcastle University, Newcastle upon Tyne, UK
| | - Simon Tual-Chalot
- Biosciences Institute, Vascular Biology and Medicine Theme, Newcastle University, Newcastle upon Tyne, UK
| | - Ioakim Spyridopoulos
- Translational and Clinical Research Institute, Vascular Biology and Medicine Theme, Newcastle University, Newcastle upon Tyne, UK
| | - Helen M Phillips
- Biosciences Institute, Vascular Biology and Medicine Theme, Newcastle University, Newcastle upon Tyne, UK
| | - Gavin D Richardson
- Biosciences Institute, Vascular Biology and Medicine Theme, Newcastle University, Newcastle upon Tyne, UK.
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5
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Liu Y, Betori RC, Pagacz J, Frost GB, Efimova EV, Wu D, Wolfgeher DJ, Bryan TM, Cohen SB, Scheidt KA, Kron SJ. Targeting telomerase reverse transcriptase with the covalent inhibitor NU-1 confers immunogenic radiation sensitization. Cell Chem Biol 2022; 29:1517-1531.e7. [PMID: 36206753 PMCID: PMC9588800 DOI: 10.1016/j.chembiol.2022.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/29/2022] [Accepted: 09/15/2022] [Indexed: 11/03/2022]
Abstract
Beyond synthesizing telomere repeats, the telomerase reverse transcriptase (TERT) also serves multiple other roles supporting cancer growth. Blocking telomerase to drive telomere erosion appears impractical, but TERT's non-canonical activities have yet to be fully explored as cancer targets. Here, we used an irreversible TERT inhibitor, NU-1, to examine impacts on resistance to conventional cancer therapies. In vitro, inhibiting TERT sensitized cells to chemotherapy and radiation. NU-1 delayed repair of double-strand breaks, resulting in persistent DNA damage signaling and cellular senescence. Although NU-1 alone did not impact growth of syngeneic CT26 tumors in BALB/c mice, it dramatically enhanced the effects of radiation, leading to immune-dependent tumor elimination. Tumors displayed persistent DNA damage, suppressed proliferation, and increased activated immune infiltrate. Our studies confirm TERT's role in limiting genotoxic effects of conventional therapy but also implicate TERT as a determinant of immune evasion and therapy resistance.
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Affiliation(s)
- Yue Liu
- Ludwig Center for Metastasis Research and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Rick C Betori
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
| | - Joanna Pagacz
- Ludwig Center for Metastasis Research and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Grant B Frost
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
| | - Elena V Efimova
- Ludwig Center for Metastasis Research and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Ding Wu
- Ludwig Center for Metastasis Research and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Donald J Wolfgeher
- Ludwig Center for Metastasis Research and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Tracy M Bryan
- Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Scott B Cohen
- Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Karl A Scheidt
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.
| | - Stephen J Kron
- Ludwig Center for Metastasis Research and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA.
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6
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Slusher AL, Kim JJJ, Ribick M, Ludlow AT. Acute Exercise Regulates hTERT Gene Expression and Alternative Splicing in the hTERT-BAC Transgenic Mouse Model. Med Sci Sports Exerc 2022; 54:931-943. [PMID: 35135999 PMCID: PMC9117413 DOI: 10.1249/mss.0000000000002868] [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] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Aerobic exercise maintains telomere length through increased human telomerase reverse transcriptase (hTERT) expression and telomerase enzyme activity. The impact of acute exercise on hTERT alternative splicing (AS) is unknown. PURPOSE This study aimed to examine hTERT AS in response to acute treadmill running. METHODS A bacterial artificial chromosome mouse model containing the 54-kilobase hTERT gene locus inserted into its genome (hTERT-BAC) was utilized. The gastrocnemius, left ventricle, and brain were excised before (Pre), upon cessation (Post), and during recovery (1, 24, 48, and 72 h; n = 5/time point) from treadmill running (30 min at 60% maximum speed). Full-length (FL) hTERT and the "minus beta" (-β) AS variant (skips exons 7 and 8 and does not code for active telomerase) were measured by gel-based and droplet digital reverse transcription-polymerase chain reaction methods. SF3B4 and SRSF2 protein expression were measured by Western blotting. RESULTS Compared with Pre, FL hTERT increased at Post before decreasing during recovery in the gastrocnemius (48 and 72 h; P ≤ 0.001) and left ventricle (24 h; P = 0.004). The percentage of FL hTERT in the gastrocnemius also increased during recovery (1 and 72 h; P ≤ 0.017), whereas a decrease was observed in the left ventricle (1, 24, and 48 h; P ≤ 0.041). hTERT decreased in the brain (48 h), whereas FL hTERT percentage remained unaltered. SF3B4 protein expression decreased throughout recovery in the gastrocnemius and tended to be associated with FL hTERT (r = -0.348, P = 0.075) and -β in opposite directions (r = 0.345, P = 0.067). CONCLUSIONS Endurance exercise increased hTERT gene expression, and altered FL hTERT splicing in contractile tissues and may maintain telomere length necessary to improve the function and health of the organism.
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Affiliation(s)
| | - Jeongjin JJ Kim
- School of Kinesiology, University of Michigan, Ann Arbor, MI
| | - Mark Ribick
- School of Kinesiology, University of Michigan, Ann Arbor, MI
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7
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Mojiri A, Walther BK, Jiang C, Matrone G, Holgate R, Xu Q, Morales E, Wang G, Gu J, Wang R, Cooke JP. Telomerase therapy reverses vascular senescence and extends lifespan in progeria mice. Eur Heart J 2021; 42:4352-4369. [PMID: 34389865 PMCID: PMC8603239 DOI: 10.1093/eurheartj/ehab547] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 03/29/2021] [Accepted: 08/12/2021] [Indexed: 12/28/2022] Open
Abstract
AIMS Hutchinson-Gilford progeria syndrome (HGPS) is an accelerated ageing syndrome associated with premature vascular disease and death due to heart attack and stroke. In HGPS a mutation in lamin A (progerin) alters nuclear morphology and gene expression. Current therapy increases the lifespan of these children only modestly. Thus, greater understanding of the underlying mechanisms of HGPS is required to improve therapy. Endothelial cells (ECs) differentiated from induced pluripotent stem cells (iPSCs) derived from these patients exhibit hallmarks of senescence including replication arrest, increased expression of inflammatory markers, DNA damage, and telomere erosion. We hypothesized that correction of shortened telomeres may reverse these measures of vascular ageing. METHODS AND RESULTS We generated ECs from iPSCs belonging to children with HGPS and their unaffected parents. Telomerase mRNA (hTERT) was used to treat HGPS ECs. Endothelial morphology and functions were assessed, as well as proteomic and transcriptional profiles with attention to inflammatory markers, DNA damage, and EC identity genes. In a mouse model of HGPS, we assessed the effects of lentiviral transfection of mTERT on measures of senescence, focusing on the EC phenotype in various organs. hTERT treatment of human HGPS ECs improved replicative capacity; restored endothelial functions such as nitric oxide generation, acetylated low-density lipoprotein uptake and angiogenesis; and reduced the elaboration of inflammatory cytokines. In addition, hTERT treatment improved cellular and nuclear morphology, in association with a normalization of the transcriptional profile, effects that may be mediated in part by a reduction in progerin expression and an increase in sirtuin 1 (SIRT1). Progeria mice treated with mTERT lentivirus manifested similar improvements, with a reduction in inflammatory and DNA damage markers and increased SIRT1 in their vasculature and other organs. Furthermore, mTERT therapy increased the lifespan of HGPS mice. CONCLUSION Vascular rejuvenation using telomerase mRNA is a promising approach for progeria and other age-related diseases.
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Affiliation(s)
- Anahita Mojiri
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
| | - Brandon K Walther
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
- Department of Biomedical Engineering, Texas A&M University, 101 Bizzell St., College Station, TX 77840, USA
| | - Chongming Jiang
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gianfranco Matrone
- British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, The University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Rhonda Holgate
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
| | - Qiu Xu
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
| | - Elisa Morales
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
| | - Guangyu Wang
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
- Center for Bioinformatics and Computational Biology, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Jianhua Gu
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
| | - Rongfu Wang
- Department of Medicine, and Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - John P Cooke
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, 6670 Bertner Ave., R10-South, Houston, TX 77030, USA
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8
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Parulekar A, Choksi A, Taye N, Totakura KVS, Firmal P, Kundu GC, Chattopadhyay S. SMAR1 suppresses the cancer stem cell population via hTERT repression in colorectal cancer cells. Int J Biochem Cell Biol 2021; 141:106085. [PMID: 34551340 DOI: 10.1016/j.biocel.2021.106085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 09/09/2021] [Accepted: 09/16/2021] [Indexed: 11/25/2022]
Abstract
One of the hallmarks of a cancer cell is the ability for indefinite proliferation leading to the immortalization of the cell. Activation of several signaling pathways leads to the immortalization of cancer cells via the reactivation of enzyme telomerase (hTERT). hTERT is active in germ cells, stem cells and also cancer cells. An earlier report from our lab suggests that SMAR1, a tumor suppressor protein, is significantly downregulated in the higher grades of colorectal cancers. Our study identifies SMAR1 as a transcriptional repressor of hTERT. We find that SMAR1 interacts with HDAC1/mSin3a co-repressor complex at the hTERT promoter and brings about HDAC1-mediated transcriptional repression of the promoter. Most solid tumors including colorectal cancer reactivate hTERT expression as it confers several advantages to the cancer cells like increased proliferation and angiogenesis. One of these non-canonical functions of hTERT is inducing the pool of cancer stem cell population. We find that in the CD133HighCD44High cancer stem cells population, SMAR1 expression is highly diminished leading to elevated hTERT expression. We also find that knockdown of SMAR1 promotes total CD133+CD44+ population and impart enhanced sphere-forming ability to the colorectal cancer cells. SMAR1 also inhibits invasion and metastasis in colorectal cancer cell lines via repression of hTERT. Our study provides evidence that downregulation of SMAR1 causes activation of hTERT leading to an increase in the cancer stem cell phenotype in colorectal cancer cells.
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Affiliation(s)
| | | | | | | | | | - Gopal C Kundu
- National Centre for Cell Science, Pune, India; Kalinga Institute of Industrial Technology, Bhubaneswar, India
| | - Samit Chattopadhyay
- National Centre for Cell Science, Pune, India; Birla Institute of Technology and Science, Goa, India.
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9
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Plyasova AA, Zhdanov DD. Alternative Splicing of Human Telomerase Reverse Transcriptase (hTERT) and Its Implications in Physiological and Pathological Processes. Biomedicines 2021; 9:526. [PMID: 34065134 PMCID: PMC8150890 DOI: 10.3390/biomedicines9050526] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/03/2021] [Accepted: 05/05/2021] [Indexed: 12/24/2022] Open
Abstract
Alternative splicing (AS) of human telomerase catalytic subunit (hTERT, human telomerase reverse transcriptase) pre-mRNA strongly regulates telomerase activity. Several proteins can regulate AS in a cell type-specific manner and determine the functions of cells. In addition to being involved in telomerase activity regulation, AS provides cells with different splice variants that may have alternative biological activities. The modulation of telomerase activity through the induction of hTERT AS is involved in the development of different cancer types and embryos, and the differentiation of stem cells. Regulatory T cells may suppress the proliferation of target human and murine T and B lymphocytes and NK cells in a contact-independent manner involving activation of TERT AS. This review focuses on the mechanism of regulation of hTERT pre-mRNA AS and the involvement of splice variants in physiological and pathological processes.
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Affiliation(s)
| | - Dmitry D. Zhdanov
- Institute of Biomedical Chemistry, Pogodinskaya st 10/8, 119121 Moscow, Russia;
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10
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Romaniuk-Drapała A, Totoń E, Konieczna N, Machnik M, Barczak W, Kowal D, Kopczyński P, Kaczmarek M, Rubiś B. hTERT Downregulation Attenuates Resistance to DOX, Impairs FAK-Mediated Adhesion, and Leads to Autophagy Induction in Breast Cancer Cells. Cells 2021; 10:cells10040867. [PMID: 33920284 PMCID: PMC8068966 DOI: 10.3390/cells10040867] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 12/13/2022] Open
Abstract
Telomerase is known to contribute to telomere maintenance and to provide cancer cell immortality. However, numerous reports are showing that the function of the enzyme goes far beyond chromosome ends. The study aimed to explore how telomerase downregulation in MCF7 and MDA-MB-231 breast cancer cells affects their ability to survive. Consequently, sensitivity to drug resistance, proliferation, and adhesion were assessed. The lentiviral-mediated human telomerase reverse transcriptase (hTERT) downregulation efficiency was performed at gene expression and protein level using qPCR and Western blot, respectively. Telomerase activity was evaluated using the Telomeric Repeat Amplification Protocol (TRAP) assay. The study revealed that hTERT downregulation led to an increased sensitivity of breast cancer cells to doxorubicin which was demonstrated in MTT and clonogenic assays. During a long-term doubling time assessment, a decreased population doubling level was observed. Interestingly, it did not dramatically affect cell cycle distribution. hTERT downregulation was accompanied by an alteration in β1-integrin- and by focal adhesion kinase (FAK)-driven pathways together with the reduction of target proteins phosphorylation, i.e., paxillin and c-Src. Additionally, autophagy activation was observed in MDA-MB-231 cells manifested by alternations in Atg5, Beclin 1, LC3II/I ratio, and p62. These results provide new evidence supporting the possible therapeutic potential of telomerase downregulation leading to induction of autophagy and cancer cells elimination.
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Affiliation(s)
- Aleksandra Romaniuk-Drapała
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland; (A.R.-D.); (E.T.); (N.K.); (D.K.)
| | - Ewa Totoń
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland; (A.R.-D.); (E.T.); (N.K.); (D.K.)
| | - Natalia Konieczna
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland; (A.R.-D.); (E.T.); (N.K.); (D.K.)
| | - Marta Machnik
- Department of Cancer Immunology, Poznan University of Medical Sciences, 60-806 Poznan, Poland;
| | - Wojciech Barczak
- Department of Head and Neck Surgery, Poznan University of Medical Sciences, The Greater Poland Cancer Centre, 61-866 Poznan, Poland;
| | - Dagmar Kowal
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland; (A.R.-D.); (E.T.); (N.K.); (D.K.)
| | - Przemysław Kopczyński
- Centre for Orthodontic Mini-Implants at the Department and Clinic of Maxillofacial Orthopedics and Orthodontics, Poznan University of Medical Sciences, 60-812 Poznan, Poland;
| | - Mariusz Kaczmarek
- Department of Immunology, Chair of Clinical Immunology, Poznań University of Medical Sciences, 5D Rokietnicka St., 60-806 Poznań, Poland;
| | - Błażej Rubiś
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland; (A.R.-D.); (E.T.); (N.K.); (D.K.)
- Correspondence: ; Tel.: +48-61-869-14-27
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11
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Telomerase Biogenesis and Activities from the Perspective of Its Direct Interacting Partners. Cancers (Basel) 2020; 12:cancers12061679. [PMID: 32599885 PMCID: PMC7352425 DOI: 10.3390/cancers12061679] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/20/2020] [Accepted: 06/22/2020] [Indexed: 12/15/2022] Open
Abstract
Telomerase reverse transcriptase (TERT)—the catalytic subunit of telomerase—is reactivated in up to 90% of all human cancers. TERT is observed in heterogenous populations of protein complexes, which are dynamically regulated in a cell type- and cell cycle-specific manner. Over the past two decades, in vitro protein–protein interaction detection methods have discovered a number of endogenous TERT binding partners in human cells that are responsible for the biogenesis and functionalization of the telomerase holoenzyme, including the processes of TERT trafficking between subcellular compartments, assembly into telomerase, and catalytic action at telomeres. Additionally, TERT have been found to interact with protein species with no known telomeric functions, suggesting that these complexes may contribute to non-canonical activities of TERT. Here, we survey TERT direct binding partners and discuss their contributions to TERT biogenesis and functions. The goal is to review the comprehensive spectrum of TERT pro-malignant activities, both telomeric and non-telomeric, which may explain the prevalence of its upregulation in cancer.
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12
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Shafi FAA, Jabbar EAK, Yousif RM, Lafta FM. Effect of exercise, synthetic anabolic steroids and protein intake on DNA damage in trained and untrained men. Meta Gene 2020. [DOI: 10.1016/j.mgene.2020.100685] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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13
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Thompson CA, Wong JM. Non-canonical Functions of Telomerase Reverse Transcriptase: Emerging Roles and Biological Relevance. Curr Top Med Chem 2020; 20:498-507. [DOI: 10.2174/1568026620666200131125110] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/10/2020] [Accepted: 01/21/2020] [Indexed: 12/11/2022]
Abstract
Increasing evidence from research on telomerase suggests that in addition to its catalytic telomere
repeat synthesis activity, telomerase may have other biologically important functions. The canonical
roles of telomerase are at the telomere ends where they elongate telomeres and maintain genomic
stability and cellular lifespan. The catalytic protein component Telomerase Reverse Transcriptase
(TERT) is preferentially expressed at high levels in cancer cells despite the existence of an alternative
mechanism for telomere maintenance (alternative lengthening of telomeres or ALT). TERT is also expressed
at higher levels than necessary for maintaining functional telomere length, suggesting other possible
adaptive functions. Emerging non-canonical roles of TERT include regulation of non-telomeric
DNA damage responses, promotion of cell growth and proliferation, acceleration of cell cycle kinetics,
and control of mitochondrial integrity following oxidative stress. Non-canonical activities of TERT primarily
show cellular protective effects, and nuclear TERT has been shown to protect against cell death
following double-stranded DNA damage, independent of its role in telomere length maintenance. TERT
has been suggested to act as a chromatin modulator and participate in the transcriptional regulation of
gene expression. TERT has also been reported to regulate transcript levels through an RNA-dependent
RNA Polymerase (RdRP) activity and produce siRNAs in a Dicer-dependent manner. At the mitochondria,
TERT is suggested to protect against oxidative stress-induced mtDNA damage and promote mitochondrial
integrity. These extra-telomeric functions of TERT may be advantageous in the context of increased
proliferation and metabolic stress often found in rapidly-dividing cancer cells. Understanding
the spectrum of non-canonical functions of telomerase may have important implications for the rational
design of anti-cancer chemotherapeutic drugs.
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Affiliation(s)
- Connor A.H. Thompson
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - Judy M.Y. Wong
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
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14
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Nuta O, Rothkamm K, Darroudi F. The Role of Telomerase in Radiation-Induced Genomic Instability. Radiat Res 2020; 193:451-459. [PMID: 32150497 DOI: 10.1667/rr15495.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Findings from previous studies have suggested that the telomerase system is involved in radiation-induced genomic instability. In this study, we investigated the involvement of telomerase in the development and processing of chromosomal damage at different cell cycle stages after irradiation of human fibroblasts. Several response criteria were investigated, including cell survival, chromosomal damage (using the micronucleus assay), G2-induced chromatid aberrations (using the conventional G2 assay as well as a chemically-induced premature chromosome condensation assay) and DNA double-strand breaks (DSBs; using γ-H2AX, 53BP1 and Rad51) in an isogenic pair of cell lines: BJ human foreskin fibroblasts and BJ1-hTERT, a telomerase-immortalized BJ cell line. To distinguish among G1, S and G2 phase, cells were co-immunostained for CENP-F and cyclin A, which are tightly regulated proteins in the cell cycle. After X-ray irradiation at doses in the range of 0.1-6 Gy, the results showed that for cell survival and micronuclei induction, where the overall effect is dominated by the cells in G1 and S phase, no difference was observed between the two cell types; in contrast, when radiation sensitivity at the G2 stage of the cell cycle was analyzed, a significantly higher number of chromatid-type aberrations (breaks and exchanges), and higher levels of γ-H2AX and of Rad51 foci were observed for the BJ cells compared to the BJ1-hTERT cells. Therefore, it can be concluded that telomerase appears to be involved in DNA DSB repair processes, mainly in the G2 phase. These data, taken overall, reinforce the notion that hTERT or other elements of the telomere/telomerase system may defend chromosome integrity in human fibroblasts by promoting repair in G2 phase of the cell cycle.
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Affiliation(s)
- Otilia Nuta
- Nazarbayev University, School of Sciences and Humanities, Department of Biology, Nur-Sultan, 010000, Kazakhstan
| | - Kai Rothkamm
- Department of Radiotherapy and Radiation Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Firouz Darroudi
- Department of Genome Scan Unlimited, 2341AJ, Oegstgeest, The Netherlands
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15
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Perera ON, Sobinoff AP, Teber ET, Harman A, Maritz MF, Yang SF, Pickett HA, Cesare AJ, Arthur JW, MacKenzie KL, Bryan TM. Telomerase promotes formation of a telomere protective complex in cancer cells. SCIENCE ADVANCES 2019; 5:eaav4409. [PMID: 31616780 PMCID: PMC6774720 DOI: 10.1126/sciadv.aav4409] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 09/09/2019] [Indexed: 05/04/2023]
Abstract
Telomerase is a ribonucleoprotein complex that catalyzes addition of telomeric DNA repeats to maintain telomeres in replicating cells. Here, we demonstrate that the telomerase protein hTERT performs an additional role at telomeres that is independent of telomerase catalytic activity yet essential for telomere integrity and cell proliferation. Short-term depletion of endogenous hTERT reduced the levels of heat shock protein 70 (Hsp70-1) and the telomere protective protein Apollo at telomeres, and induced telomere deprotection and cell cycle arrest, in the absence of telomere shortening. Short-term expression of hTERT promoted colocalization of Hsp70-1 with telomeres and Apollo and reduced numbers of deprotected telomeres, in a manner independent of telomerase catalytic activity. These data reveal a previously unidentified noncanonical function of hTERT that promotes formation of a telomere protective complex containing Hsp70-1 and Apollo and is essential for sustained proliferation of telomerase-positive cancer cells, likely contributing to the known cancer-promoting effects of both hTERT and Hsp70-1.
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Affiliation(s)
- Omesha N. Perera
- Cell Biology Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Alexander P. Sobinoff
- Telomere Length Regulation Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Erdahl T. Teber
- Bioinformatics Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Ashley Harman
- Cell Biology Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Michelle F. Maritz
- Children’s Cancer Institute, School of Women’s and Children’s Health, University of NSW, NSW 2052, Australia
| | - Sile F. Yang
- 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
| | - Anthony J. Cesare
- Genome Integrity Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Jonathan W. Arthur
- Bioinformatics Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Karen L. MacKenzie
- Children’s Cancer Institute, School of Women’s and Children’s Health, University of NSW, NSW 2052, Australia
| | - Tracy M. Bryan
- Cell Biology Unit, Children’s Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
- Corresponding author.
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16
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Insights into Telomerase/hTERT Alternative Splicing Regulation Using Bioinformatics and Network Analysis in Cancer. Cancers (Basel) 2019; 11:cancers11050666. [PMID: 31091669 PMCID: PMC6562651 DOI: 10.3390/cancers11050666] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 05/10/2019] [Accepted: 05/13/2019] [Indexed: 01/08/2023] Open
Abstract
The reactivation of telomerase in cancer cells remains incompletely understood. The catalytic component of telomerase, hTERT, is thought to be the limiting component in cancer cells for the formation of active enzymes. hTERT gene expression is regulated at several levels including chromatin, DNA methylation, transcription factors, and RNA processing events. Of these regulatory events, RNA processing has received little attention until recently. RNA processing and alternative splicing regulation have been explored to understand how hTERT is regulated in cancer cells. The cis- and trans-acting factors that regulate the alternative splicing choice of hTERT in the reverse transcriptase domain have been investigated. Further, it was discovered that the splicing factors that promote the production of full-length hTERT were also involved in cancer cell growth and survival. The goals are to review telomerase regulation via alternative splicing and the function of hTERT splicing variants and to point out how bioinformatics approaches are leading the way in elucidating the networks that regulate hTERT splicing choice and ultimately cancer growth.
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17
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Hadzic M, Haveric S, Haveric A, Lojo-Kadric N, Galic B, Ramic J, Pojskic L. Bioflavonoids protect cells against halogenated boroxine-induced genotoxic damage by upregulation of hTERT expression. ACTA ACUST UNITED AC 2018; 74:125-129. [DOI: 10.1515/znc-2018-0132] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 11/23/2018] [Indexed: 12/22/2022]
Abstract
Abstract
Plant bioflavonoids are widely present in the human diet and have various protective properties. In this study, we have demonstrated the capacity of delphinidin and luteolin to increase human telomerase reverse transcriptase (hTERT) expression level and act as protective agents against halogenated boroxine-induced genotoxic damage. Halogenated boroxine K2(B3O3F4OH) (HB), is a novel compound with potential for the treatment of both benign and malignant skin changes. In vivo and in vitro studies have confirmed the inhibitory effects of HB on carcinoma cell proliferation and cell cycle progression as well as enzyme inhibition. However, minor genotoxic effects of HB are registered in higher applied concentrations, but those can be suppressed by in vitro addition of delphinidin and luteolin in appropriate concentrations. Fresh peripheral blood samples were cultivated for 72 h followed by independent and concomitant treatments of HB with luteolin or delphinidin. We analyzed the differences in relative hTERT expression between series of treatments compared with controls, which were based on normalized ratios with housekeeping genes. The obtained results have shown that selected bioflavonoids induce upregulation of hTERT that may contribute to the repair of genotoxic damage in vitro.
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Affiliation(s)
- Maida Hadzic
- Institute for Genetic Engineering and Biotechnology , University of Sarajevo , Zmaja od Bosne 8 , 71000 Sarajevo , Bosnia and Herzegovina
| | - Sanin Haveric
- Institute for Genetic Engineering and Biotechnology , University of Sarajevo , Zmaja od Bosne 8 , 71000 Sarajevo , Bosnia and Herzegovina
| | - Anja Haveric
- Institute for Genetic Engineering and Biotechnology , University of Sarajevo , Zmaja od Bosne 8 , 71000 Sarajevo , Bosnia and Herzegovina
| | - Naida Lojo-Kadric
- Institute for Genetic Engineering and Biotechnology , University of Sarajevo , Zmaja od Bosne 8 , 71000 Sarajevo , Bosnia and Herzegovina
| | - Borivoj Galic
- Faculty of Science, Department for Chemistry , University of Sarajevo , Zmaja od Bosne 33-35 , 71000 Sarajevo , Bosnia and Herzegovina
| | - Jasmin Ramic
- Institute for Genetic Engineering and Biotechnology , University of Sarajevo , Zmaja od Bosne 8 , 71000 Sarajevo , Bosnia and Herzegovina
| | - Lejla Pojskic
- Institute for Genetic Engineering and Biotechnology , University of Sarajevo , Zmaja od Bosne 8 , 71000 Sarajevo , Bosnia and Herzegovina
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18
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Gopal RK, Kübler K, Calvo SE, Polak P, Livitz D, Rosebrock D, Sadow PM, Campbell B, Donovan SE, Amin S, Gigliotti BJ, Grabarek Z, Hess JM, Stewart C, Braunstein LZ, Arndt PF, Mordecai S, Shih AR, Chaves F, Zhan T, Lubitz CC, Kim J, Iafrate AJ, Wirth L, Parangi S, Leshchiner I, Daniels GH, Mootha VK, Dias-Santagata D, Getz G, McFadden DG. Widespread Chromosomal Losses and Mitochondrial DNA Alterations as Genetic Drivers in Hürthle Cell Carcinoma. Cancer Cell 2018; 34:242-255.e5. [PMID: 30107175 PMCID: PMC6121811 DOI: 10.1016/j.ccell.2018.06.013] [Citation(s) in RCA: 155] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/30/2018] [Accepted: 06/27/2018] [Indexed: 12/24/2022]
Abstract
Hürthle cell carcinoma of the thyroid (HCC) is a form of thyroid cancer recalcitrant to radioiodine therapy that exhibits an accumulation of mitochondria. We performed whole-exome sequencing on a cohort of primary, recurrent, and metastatic tumors, and identified recurrent mutations in DAXX, TP53, NRAS, NF1, CDKN1A, ARHGAP35, and the TERT promoter. Parallel analysis of mtDNA revealed recurrent homoplasmic mutations in subunits of complex I of the electron transport chain. Analysis of DNA copy-number alterations uncovered widespread loss of chromosomes culminating in near-haploid chromosomal content in a large fraction of HCC, which was maintained during metastatic spread. This work uncovers a distinct molecular origin of HCC compared with other thyroid malignancies.
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Affiliation(s)
- Raj K Gopal
- Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Cancer Center, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Kirsten Kübler
- Cancer Center, Massachusetts General Hospital, Boston, MA 02114, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Sarah E Calvo
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Paz Polak
- Cancer Center, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Dimitri Livitz
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Peter M Sadow
- Cancer Center, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Braidie Campbell
- Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Cancer Center, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Samuel E Donovan
- Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Cancer Center, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Salma Amin
- Cancer Center, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Surgery, Massachusetts General Hospital, Boston, MA 02114, USA
| | | | - Zenon Grabarek
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Julian M Hess
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Chip Stewart
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Peter F Arndt
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Scott Mordecai
- Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Angela R Shih
- Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Frances Chaves
- Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Tiannan Zhan
- Institute for Technology Assessment, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Carrie C Lubitz
- Cancer Center, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Surgery, Massachusetts General Hospital, Boston, MA 02114, USA; Institute for Technology Assessment, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Jiwoong Kim
- Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - A John Iafrate
- Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Lori Wirth
- Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Cancer Center, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Sareh Parangi
- Cancer Center, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Surgery, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA
| | | | - Gilbert H Daniels
- Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Cancer Center, Massachusetts General Hospital, Boston, MA 02114, USA; Thyroid Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Vamsi K Mootha
- Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Dora Dias-Santagata
- Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Gad Getz
- Cancer Center, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Harvard Medical School, Boston, MA 02115, USA.
| | - David G McFadden
- Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Thyroid Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Internal Medicine, Division of Endocrinology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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19
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Thompson CAH, Gu A, Yang SY, Mathew V, Fleisig HB, Wong JMY. Transient Telomerase Inhibition with Imetelstat Impacts DNA Damage Signals and Cell-Cycle Kinetics. Mol Cancer Res 2018; 16:1215-1225. [PMID: 29759988 DOI: 10.1158/1541-7786.mcr-17-0772] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/20/2018] [Accepted: 04/27/2018] [Indexed: 11/16/2022]
Abstract
Telomerase is the ribonucleoprotein reverse transcriptase that catalyzes the synthesis of telomeres at the ends of linear chromosomes and contributes to proper telomere-loop (T-loop) formation. Formation of the T-loop, an obligate step before cell division can proceed, requires the generation of a 3'-overhang on the G-rich strand of telomeric DNA via telomerase or C-strand specific nucleases. Here, it is discovered that telomerase activity is critical for efficient cell-cycle progression using transient chemical inhibition by the telomerase inhibitor, imetelstat. Telomerase inhibition changed cell cycle kinetics and increased the proportion of cells in G2-phase, suggesting delayed clearance through this checkpoint. Investigating the possible contribution of unstructured telomere ends to these cell-cycle distribution changes, it was observed that imetelstat treatment induced γH2AX DNA damage foci in a subset of telomerase-positive cells but not telomerase-negative primary human fibroblasts. Chromatin-immunoprecipitation with γH2AX antibodies demonstrated imetelstat treatment-dependent enrichment of this DNA damage marker at telomeres. Notably, the effects of telomerase inhibition on cell cycle profile alterations were abrogated by pharmacological inhibition of the DNA-damage-repair transducer, ATM. Also, imetelstat potentiation of etoposide, a DNA-damaging drug that acts preferentially during S-G2 phases of the cell cycle, depends on functional ATM signaling. Thus, telomerase inhibition delays the removal of ATM-dependent DNA damage signals from telomeres in telomerase-positive cancer cells and interferes with cell cycle progression through G2Implications: This study demonstrates that telomerase activity directly facilitates the progression of the cell cycle through modulation of transient telomere dysfunction signals. Mol Cancer Res; 16(8); 1215-25. ©2018 AACR.
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Affiliation(s)
- Connor A H Thompson
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alice Gu
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sunny Y Yang
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Veena Mathew
- Terry Fox Laboratory, British Columbia Cancer Research Centre, Vancouver, BC Cancer Agency, British Columbia, Canada
| | - Helen B Fleisig
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Judy M Y Wong
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
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20
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Exploiting TERT dependency as a therapeutic strategy for NRAS-mutant melanoma. Oncogene 2018; 37:4058-4072. [PMID: 29695835 PMCID: PMC6062502 DOI: 10.1038/s41388-018-0247-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 02/21/2018] [Accepted: 02/23/2018] [Indexed: 12/31/2022]
Abstract
Targeting RAS is one of the greatest challenges in cancer therapy. Oncogenic mutations in NRAS are present in over 25% of melanomas and patients whose tumors harbor NRAS mutations have limited therapeutic options and poor prognosis. Thus far, there are no clinical agents available to effectively target NRAS or any other RAS oncogene. An alternative approach is to identify and target critical tumor vulnerabilities or non-oncogene addictions that are essential for tumor survival. We investigated the consequences of NRAS blockade in NRAS-mutant melanoma and show that decreased expression of the telomerase catalytic subunit, TERT, is a major consequence. TERT silencing or treatment of NRAS-mutant melanoma with the telomerase-dependent telomere uncapping agent, 6-thio-2'-deoxyguanosine (6-thio-dG), led to rapid cell death, along with evidence of both telomeric and non-telomeric DNA damage, increased ROS levels, and upregulation of a mitochondrial antioxidant adaptive response. Combining 6-thio-dG with the mitochondrial inhibitor Gamitrinib attenuated this adaptive response and more effectively suppressed NRAS-mutant melanoma. Our study uncovers a robust dependency of NRAS-mutant melanoma on TERT, and provides proof-of-principle for a new combination strategy to combat this class of tumors, which could be expanded to other tumor types.
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21
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Telomere Biology and Thoracic Aortic Aneurysm. Int J Mol Sci 2017; 19:ijms19010003. [PMID: 29267201 PMCID: PMC5795955 DOI: 10.3390/ijms19010003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 12/13/2017] [Accepted: 12/19/2017] [Indexed: 12/27/2022] Open
Abstract
Ascending aortic aneurysms are mostly asymptomatic and present a great risk of aortic dissection or perforation. Consequently, ascending aortic aneurysms are a source of lethality with increased age. Biological aging results in progressive attrition of telomeres, which are the repetitive DNA sequences at the end of chromosomes. These telomeres play an important role in protection of genomic DNA from end-to-end fusions. Telomere maintenance and telomere attrition-associated senescence of endothelial and smooth muscle cells have been indicated to be part of the pathogenesis of degenerative vascular diseases. This systematic review provides an overview of telomeres, telomere-associated proteins and telomerase to the formation and progression of aneurysms of the thoracic ascending aorta. A better understanding of telomere regulation in the vascular pathology might provide new therapeutic approaches. Measurements of telomere length and telomerase activity could be potential prognostic biomarkers for increased risk of death in elderly patients suffering from an aortic aneurysm.
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22
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Zhang MY, Wang JP. A multi-target protein of hTERTR-FAM96A presents significant anticancer potent in the treatment of hepatocellular carcinoma. Tumour Biol 2017; 39:1010428317698341. [PMID: 28443470 DOI: 10.1177/1010428317698341] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The abilities to escape apoptosis induced by anticancer drugs are an essential factor of carcinogenesis and a hallmark of resistance to cancer therapy. In this study, we identified hTERTR-FAM96A (human telomerase reverse transcriptase–family with sequence similarity 96 member A) as a new efficient agent for apoptosome-activating and anti-tumor protein and investigated the potential tumor suppressor function in hepatocellular carcinoma. The hTERTR-FAM96A fusion protein was constructed by genetic engineering and its anticancer function of hTERTR-FAM96A was explored in vitro and in vivo by investigating the possible preclinical outcomes. Effects of hTERTR-FAM96A on improvement of apoptotic sensitivity and inhibition of migration and invasion were examined in cancer cells and tumors. Our results showed that the therapeutic effects of hTERTR-FAM96A were highly effective for inhibiting tumor growth and inducing apoptosis of hepatocellular carcinoma cells in H22-bearing nude mice. The hTERTR-FAM96A fusion protein could specifically bind with Apaf-1 and hTERT, which further induced apoptosis of hepatocellular carcinoma cells and improved apoptosis sensitivity. Our results indicated that hTERTR-FAM96A treatment enhanced cytotoxic effects by upregulation of cytotoxic T lymphocyte responses, interferon-γ release, and T lymphocyte infiltration. In addition, hTERTR-FAM96A led to tumor-specific immunologic cytotoxicity through increasing apoptotic body on hepatocellular tumors. Furthermore, hTERTR-FAM96A dramatically inhibited tumor growth, reduced death rate, and prolonged mice survival in hepatocellular carcinoma mice derived from three independent hepatocellular carcinoma mice cohorts compared to control groups. In summary, our data suggest that hTERTR-FAM96A may serve as an efficient anti-tumor agent for the treatment of hepatocellular carcinoma.
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Affiliation(s)
- Meng-Yu Zhang
- Department of Hepatobiliary Surgery, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Jie-Ping Wang
- Department of Rehabilitation, The Affiliated Hospital of Southwest Medical University, Luzhou, China
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23
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Kara M, Ozcagli E, Fragkiadaki P, Kotil T, Stivaktakis PD, Spandidos DA, Tsatsakis AM, Alpertunga B. Determination of DNA damage and telomerase activity in stanozolol-treated rats. Exp Ther Med 2017; 13:614-618. [PMID: 28352339 PMCID: PMC5348646 DOI: 10.3892/etm.2016.3974] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/02/2016] [Indexed: 01/13/2023] Open
Abstract
Anabolic androgenic steroids (AAS) are performance-enhancing drugs commonly abused by atheletes. Stanozolol is a synthetic testosterone-derived anabolic steroid. Although it is well known that AAS have several side-effects, there are only few toxicological studies available on the toxic effects and mechanisms of action of stanozolol. The aim of this study was to investigate the genotoxic effects of stanozolol and to determine its effects on telomerase activity in Sprague-Dawley male rats. For this purpose, 34 male rats were divided into 5 groups as follows: i) the control group (n=5); ii) the propylene glycol (PG)-treated group (n=5); iii) the stanozolol-treated group (n=8); iv) the PG-treated group subjected to exercise (n=8); and v) the stanozolol-treated group subjected to exercise (n=8). PG is used as a solvent control in our study. Stanozolol (5 mg/kg) and PG (1 ml/kg) were injected subcutaneously 5 days/week for 28 days. After 28 days, the animals were sacrificed, and DNA damage evaluation (comet assay) and telomerase activity assays were then performed using peripheral blood mononuclear cells (PBMCs). Telomerase activity was measured by using the TeloTAGGG Telomerase PCR ELISA PLUS kit. The results of this study revealed that stanozolol treatment induced DNA damage, while exercise exerted a protective effect. Stanozolol treatment without exercise stimulation was associated with a significant increase in telomerase activity in the PBMCs.
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Affiliation(s)
- Mehtap Kara
- Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Istanbul University, Istanbul 34116, Turkey
| | - Eren Ozcagli
- Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Istanbul University, Istanbul 34116, Turkey
| | - Persefoni Fragkiadaki
- Center of Toxicology Science and Research, Medical School, University of Crete, Heraklion 71003, Greece
| | - Tugba Kotil
- Department of Histology and Embryology, School of Medicine, Istanbul University, Istanbul 34116, Turkey
| | | | - Demetrios A. Spandidos
- Laboratory of Clinical Virology, Medical School, University of Crete, Heraklion 71003, Greece
| | - Aristides M. Tsatsakis
- Center of Toxicology Science and Research, Medical School, University of Crete, Heraklion 71003, Greece
| | - Buket Alpertunga
- Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Istanbul University, Istanbul 34116, Turkey
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24
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Ali M, Devkota S, Roh JI, Lee J, Lee HW. Telomerase reverse transcriptase induces basal and amino acid starvation-induced autophagy through mTORC1. Biochem Biophys Res Commun 2016; 478:1198-204. [DOI: 10.1016/j.bbrc.2016.08.094] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 08/16/2016] [Indexed: 01/06/2023]
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25
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Chen X, Wang C, Guan S, Liu Y, Han L, Cheng Y. Zidovudine, abacavir and lamivudine increase the radiosensitivity of human esophageal squamous cancer cell lines. Oncol Rep 2016; 36:239-46. [PMID: 27220342 DOI: 10.3892/or.2016.4819] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 02/26/2016] [Indexed: 11/06/2022] Open
Abstract
Telomerase is a type of reverse transcriptase that is overexpressed in almost all human tumor cells, but not in normal tissues, which provides an opportunity for radiosensitization targeting telomerase. Zidovudine, abacavir and lamivudine are reverse transcriptase inhibitors that have been applied in clinical practice for several years. We sought to explore the radiosensitization effect of these three drugs on human esophageal cancer cell lines. Eca109 and Eca9706 cells were treated with zidovudine, abacavir and lamivudine for 48 h before irradiation was administered. Samples were collected 1 h after irradiation. Clonal efficiency assay was used to evaluate the effect of the combination of these drugs with radiation doses of 2, 4, 6 and 8 Gy. DNA damage was measured by comet assay. Telomerase activity (TA) and relative telomere length (TL) were detected and evaluated by real-time PCR. Apoptosis rates were assessed by flow cytometric analysis. The results showed that all the drugs tested sensitized the esophageal squamous cell carcinoma (ESCC) cell lines to radiation through an increase in radiation-induced DNA damage and cell apoptosis, deregulation of TA and decreasing the shortened TL caused by radiation. Each of the drugs investigated (zidovudine, abacavir and lamivudine) could be used for sensitizing human esophageal cancer cell lines to radiation. Consequently, the present study supports the potential of these three drugs as therapeutic agents for the radiosensitization of esophageal squamous cell cancer.
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Affiliation(s)
- Xuan Chen
- Department of Radiation Oncology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China
| | - Cong Wang
- Department of Radiation Oncology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China
| | - Shanghui Guan
- Department of Radiation Oncology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China
| | - Yuan Liu
- Department of Radiation Oncology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China
| | - Lihui Han
- Department of Radiation Oncology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China
| | - Yufeng Cheng
- Department of Radiation Oncology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China
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Liu H, Liu Q, Ge Y, Zhao Q, Zheng X, Zhao Y. hTERT promotes cell adhesion and migration independent of telomerase activity. Sci Rep 2016; 6:22886. [PMID: 26971878 PMCID: PMC4789728 DOI: 10.1038/srep22886] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 02/23/2016] [Indexed: 02/07/2023] Open
Abstract
hTERT, a catalytic component of human telomerase, is undetectable in normal somatic cells but up-regulated in cancer and stem cells where telomere length is maintained by telomerase. Accumulated evidence indicates that hTERT may have noncanonical functions beyond telomerase by regulating the expression of particular genes. However, comprehensive identification of the genes regulated by hTERT is unavailable. In this report, we expressed WT hTERT and hTERTmut which displays dysfunctional catalytic activity, in human U2OS cancer cells and VA-13 immortalized fibroblast cells, both of which lack endogenous hTERT and hTR expression. Changes in gene expression induced by hTERT and hTERT-mut expression were determined by genome-wide RNA-seq and verified by qPCR. Our results showed that hTERT affects different genes in two cell lines, implying that the regulation of gene expression by hTERT is indirect and cell type dependent. Moreover, functional analysis identifies cell adhesion-related genes that have been changed by hTERT in both cell lines. Adhesion experiments revealed that hTERT expression significantly increases cell adhesion. Monolayer wound healing and transwell assays demonstrated increased cell migration upon hTERT expression. These results provide new evidence to support a noncanonical function for hTERT in promoting tumorigenesis.
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Affiliation(s)
- Haiying Liu
- Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 P. R. China.,Collaborative Innovation Center of High Performance Computing, National University of Defense Technology, Changsha 410073, P. R. China
| | - Qianqian Liu
- Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 P. R. China.,Collaborative Innovation Center of High Performance Computing, National University of Defense Technology, Changsha 410073, P. R. China
| | - Yuanlong Ge
- Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 P. R. China.,Collaborative Innovation Center of High Performance Computing, National University of Defense Technology, Changsha 410073, P. R. China
| | - Qi Zhao
- Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 P. R. China
| | - Xiaohui Zheng
- Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 P. R. China.,Collaborative Innovation Center of High Performance Computing, National University of Defense Technology, Changsha 410073, P. R. China
| | - Yong Zhao
- Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 P. R. China.,Collaborative Innovation Center of High Performance Computing, National University of Defense Technology, Changsha 410073, P. R. China
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27
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de Oliveira-Júnior RJ, Ueira-Vieira C, Sena AAS, Reis CF, Mineo JR, Goulart LR, Morelli S. Chromosomal disruption and rearrangements during murine sarcoma development converge to stable karyotypic formation kept by telomerase overexpression. J Biomed Sci 2016; 23:22. [PMID: 26841871 PMCID: PMC4739385 DOI: 10.1186/s12929-016-0230-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 01/12/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Tumor initiation presents a complex and unstable genomic landscape; one of the earliest hallmark events of cancer, and its progression is probably based on selection mechanisms under specific environments that lead to functional tumor cell speciation. We hypothesized that viable tumor phenotypes possess common and highly stable karyotypes and their proliferation is facilitated by an attuned high telomerase activity. Very few investigations have focused on the evolution of common chromosomal rearrangements associated to molecular events that result in functional phenotypes during tumor development. RESULTS We have used cytogenetic, flow cytometry and cell culture tools to investigate chromosomal rearrangements and clonality during cancer development using the murine sarcoma TG180 model, and also molecular biology techniques to establish a correlation between chromosome instability and telomerase activity, since telomeres are highly affected during cancer evolution. Cytogenetic analysis showed a near-tetraploid karyotype originated by endoreduplication. Chromosomal rearrangements were random events in response to in vitro conditions, but a stable karyotypic equilibrium was achieved during tumor progression in different in vivo conditions, suggesting that a specific microenvironment may stabilize the chromosomal number and architecture. Specific chromosome aberrations (marker chromosomes) and activated regions (rDNAs) were ubiquitous in the karyotype, suggesting that the conservation of these patterns may be advantageous for tumor progression. High telomerase expression was also correlated with the chromosomal rearrangements stabilization. CONCLUSIONS Our data reinforce the notion that the sarcoma cell evolution converges from a highly unstable karyotype to relatively stable and functional chromosome rearrangements, which are further enabled by telomerase overexpression.
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Affiliation(s)
| | - Carlos Ueira-Vieira
- Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, MG, Brazil
| | | | - Carolina Fernandes Reis
- Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, MG, Brazil
| | - José Roberto Mineo
- Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, MG, Brazil
| | - Luiz Ricardo Goulart
- Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, MG, Brazil. .,Department of Medical Microbiology and Immunology, University of California Davis, Davis, CA, USA.
| | - Sandra Morelli
- Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, MG, Brazil.
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