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Kuhn CK, Meister J, Kreft S, Stiller M, Puppel SH, Zaremba A, Scheffler B, Ullrich V, Schöneberg T, Schadendorf D, Horn S. TERT expression is associated with metastasis from thin primaries, exhausted CD4+ T cells in melanoma and with DNA repair across cancer entities. PLoS One 2023; 18:e0281487. [PMID: 37418389 PMCID: PMC10328343 DOI: 10.1371/journal.pone.0281487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 06/20/2023] [Indexed: 07/09/2023] Open
Abstract
Telomerase reverse transcriptase (TERT) promoter mutations occur frequently in cancer, have been associated with increased TERT expression and cell proliferation, and could potentially influence therapeutic regimens for melanoma. As the role of TERT expression in malignant melanoma and the non-canonical functions of TERT remain understudied, we aimed to extend the current knowledge on the impact of TERT promoter mutations and expression alterations in tumor progression by analyzing several highly annotated melanoma cohorts. Using multivariate models, we found no consistent association for TERT promoter mutations or TERT expression with the survival rate in melanoma cohorts under immune checkpoint inhibition. However, the presence of CD4+ T cells increased with TERT expression and correlated with the expression of exhaustion markers. While the frequency of promoter mutations did not change with Breslow thickness, TERT expression was increased in metastases arising from thinner primaries. As single-cell RNA-sequencing (RNA-seq) showed that TERT expression was associated with genes involved in cell migration and dynamics of the extracellular matrix, this suggests a role of TERT during invasion and metastasis. Co-regulated genes found in several bulk tumors and single-cell RNA-seq cohorts also indicated non-canonical functions of TERT related to mitochondrial DNA stability and nuclear DNA repair. This pattern was also evident in glioblastoma and across other entities. Hence, our study adds to the role of TERT expression in cancer metastasis and potentially also immune resistance.
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Affiliation(s)
- Christina Katharina Kuhn
- Rudolf Schönheimer Institute of Biochemistry, University of Leipzig, Medical Faculty, Leipzig, Germany
| | - Jaroslawna Meister
- Rudolf Schönheimer Institute of Biochemistry, University of Leipzig, Medical Faculty, Leipzig, Germany
- Institute for Clinical Diabetology, German Diabetes Centre, Leibniz Centre for Diabetes Research at Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sophia Kreft
- Department of Dermatology, University Hospital Essen, University Duisburg-Essen, and German Cancer Consortium Partner Site Essen/Düsseldorf, Essen, Germany
| | - Mathias Stiller
- Institute of Pathology, University of Leipzig Medical Center, Leipzig, Germany
| | - Sven-Holger Puppel
- Rudolf Schönheimer Institute of Biochemistry, University of Leipzig, Medical Faculty, Leipzig, Germany
| | - Anne Zaremba
- Department of Dermatology, University Hospital Essen, University Duisburg-Essen, and German Cancer Consortium Partner Site Essen/Düsseldorf, Essen, Germany
| | - Björn Scheffler
- DKFZ-Division Translational Neurooncology at the West German Cancer Center, University Hospital Essen/University of Duisburg-Essen, Essen, Germany
| | - Vivien Ullrich
- DKFZ-Division Translational Neurooncology at the West German Cancer Center, University Hospital Essen/University of Duisburg-Essen, Essen, Germany
| | - Torsten Schöneberg
- Rudolf Schönheimer Institute of Biochemistry, University of Leipzig, Medical Faculty, Leipzig, Germany
- School of Medicine, University of Global Health Equity, Kigali, Rwanda
| | - Dirk Schadendorf
- Department of Dermatology, University Hospital Essen, University Duisburg-Essen, and German Cancer Consortium Partner Site Essen/Düsseldorf, Essen, Germany
| | - Susanne Horn
- Rudolf Schönheimer Institute of Biochemistry, University of Leipzig, Medical Faculty, Leipzig, Germany
- Department of Dermatology, University Hospital Essen, University Duisburg-Essen, and German Cancer Consortium Partner Site Essen/Düsseldorf, Essen, Germany
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Beyer AM, Norwood Toro LE, Hughes WE, Young M, Clough AV, Gao F, Medhora M, Audi SH, Jacobs ER. Autophagy, TERT, and mitochondrial dysfunction in hyperoxia. Am J Physiol Heart Circ Physiol 2021; 321:H985-H1003. [PMID: 34559580 PMCID: PMC8616608 DOI: 10.1152/ajpheart.00166.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 08/31/2021] [Accepted: 09/16/2021] [Indexed: 02/06/2023]
Abstract
Ventilation with gases containing enhanced fractions of oxygen is the cornerstone of therapy for patients with hypoxia and acute respiratory distress syndrome. Yet, hyperoxia treatment increases free reactive oxygen species (ROS)-induced lung injury, which is reported to disrupt autophagy/mitophagy. Altered extranuclear activity of the catalytic subunit of telomerase, telomerase reverse transcriptase (TERT), plays a protective role in ROS injury and autophagy in the systemic and coronary endothelium. We investigated interactions between autophagy/mitophagy and TERT that contribute to mitochondrial dysfunction and pulmonary injury in cultured rat lung microvascular endothelial cells (RLMVECs) exposed in vitro, and rat lungs exposed in vivo to hyperoxia for 48 h. Hyperoxia-induced mitochondrial damage in rat lungs [TOMM20, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)], which was paralleled by increased markers of inflammation [myeloperoxidase (MPO), IL-1β, TLR9], impaired autophagy signaling (Beclin-1, LC3B-II/1, and p62), and decreased the expression of TERT. Mitochondrial-specific autophagy (mitophagy) was not altered, as hyperoxia increased expression of Pink1 but not Parkin. Hyperoxia-induced mitochondrial damage (TOMM20) was more pronounced in rats that lack the catalytic subunit of TERT and resulted in a reduction in cellular proliferation rather than cell death in RLMVECs. Activation of TERT or autophagy individually offset mitochondrial damage (MTT). Combined activation/inhibition failed to alleviate hyperoxic-induced mitochondrial damage in vitro, whereas activation of autophagy in vivo decreased mitochondrial damage (MTT) in both wild type (WT) and rats lacking TERT. Functionally, activation of either TERT or autophagy preserved transendothelial membrane resistance. Altogether, these observations show that activation of autophagy/mitophagy and/or TERT mitigate loss of mitochondrial function and barrier integrity in hyperoxia.NEW & NOTEWORTHY In cultured pulmonary artery endothelial cells and in lungs exposed in vivo to hyperoxia, autophagy is activated, but clearance of autophagosomes is impaired in a manner that suggests cross talk between TERT and autophagy. Stimulation of autophagy prevents hyperoxia-induced decreases in mitochondrial metabolism and sustains monolayer resistance. Hyperoxia increases mitochondrial outer membrane (TOMM20) protein, decreases mitochondrial function, and reduces cellular proliferation without increasing cell death.
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Affiliation(s)
- Andreas M Beyer
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Laura E Norwood Toro
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - William E Hughes
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Micaela Young
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Anne V Clough
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
- Research Service, Zablocki Veterans Affairs Medical Center, Milwaukee Wisconsin
- Department of Mathematics, Statistics and Computer Science, Marquette University, Milwaukee, Wisconsin
| | - Feng Gao
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Meetha Medhora
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Research Service, Zablocki Veterans Affairs Medical Center, Milwaukee Wisconsin
| | - Said H Audi
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
- Research Service, Zablocki Veterans Affairs Medical Center, Milwaukee Wisconsin
- Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin
| | - Elizabeth R Jacobs
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Research Service, Zablocki Veterans Affairs Medical Center, Milwaukee Wisconsin
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Nemirovich-Danchenko NM, Khodanovich MY. Telomerase Gene Editing in the Neural Stem Cells in vivo as a Possible New Approach against Brain Aging. RUSS J GENET+ 2020. [DOI: 10.1134/s1022795420040092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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4
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Detection of mRNA of Telomerase Protein in Benign Naevi and Melanomas Using RNAscope. Appl Immunohistochem Mol Morphol 2020; 28:36-41. [DOI: 10.1097/pai.0000000000000690] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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5
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Zhdanov DD, Plyasova AA, Gladilina YA, Pokrovsky VS, Grishin DV, Grachev VA, Orlova VS, Pokrovskaya MV, Alexandrova SS, Lobaeva TA, Sokolov NN. Inhibition of telomerase activity by splice-switching oligonucleotides targeting the mRNA of the telomerase catalytic subunit affects proliferation of human CD4 + T lymphocytes. Biochem Biophys Res Commun 2019; 509:790-796. [PMID: 30612734 DOI: 10.1016/j.bbrc.2018.12.186] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 12/31/2018] [Indexed: 02/08/2023]
Abstract
Telomerase activity is regulated at the mRNA level by alternative splicing (AS) of its catalytic subunit hTERT. The aim of this study was to define the ability of splice-switching oligonucleotides (SSOs) that pair with hTERT pre-mRNA to induce AS and inhibit telomerase activity in human CD4+ T lymphocytes. SSOs that blocked the binding of a single splicing regulatory protein, SRp20 or SRp40, to its site within intron 8 of hTERT pre-mRNA demonstrated rather moderate capacities to induce AS and inhibit telomerase. However, a SSO that blocked the interaction of both SRp20 and SRp40 proteins with pre-mRNA was the most active. Cultivation of lymphocytes with spliced hTERT and inhibited telomerase resulted in the reduction of proliferative activity without significant induction of cell death. These results should facilitate further investigation of telomerase activity regulation, and antitelomerase SSOs could become promising agents for antiproliferative cell therapy.
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Affiliation(s)
- Dmitry D Zhdanov
- Institute of Biomedical Chemistry, 10/8 Pogodinskaya st, 119121, Moscow, Russia; Рeoples' Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya Street, 117198, Moscow, Russia.
| | - Anna A Plyasova
- Institute of Biomedical Chemistry, 10/8 Pogodinskaya st, 119121, Moscow, Russia
| | - Yulia A Gladilina
- Institute of Biomedical Chemistry, 10/8 Pogodinskaya st, 119121, Moscow, Russia
| | - Vadim S Pokrovsky
- Institute of Biomedical Chemistry, 10/8 Pogodinskaya st, 119121, Moscow, Russia; Рeoples' Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya Street, 117198, Moscow, Russia; N.N. Blokhin Cancer Research Center, 24 Kashirskoe Shosse, 115478, Moscow, Russia
| | - Dmitry V Grishin
- Institute of Biomedical Chemistry, 10/8 Pogodinskaya st, 119121, Moscow, Russia
| | - Vladimir A Grachev
- Рeoples' Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya Street, 117198, Moscow, Russia
| | - Valentina S Orlova
- Рeoples' Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya Street, 117198, Moscow, Russia
| | | | | | - Tatiana A Lobaeva
- Рeoples' Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya Street, 117198, Moscow, Russia
| | - Nikolay N Sokolov
- Institute of Biomedical Chemistry, 10/8 Pogodinskaya st, 119121, Moscow, Russia
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Bian C, Zhong M, Nisar MF, Wu Y, Ouyang M, Bartsch JW, Zhong JL. A novel heme oxygenase-1 splice variant, 14kDa HO-1, promotes cell proliferation and increases relative telomere length. Biochem Biophys Res Commun 2018; 500:429-434. [PMID: 29660345 DOI: 10.1016/j.bbrc.2018.04.096] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 04/12/2018] [Indexed: 12/16/2022]
Abstract
Alternative splicing is a routine phenomenon which greatly increases the diversity of proteins in eukaryotic cells. In humans, most multi-exonic genes are alternatively spliced and their splice variants confer distinct functions. Heme oxygenase-1 (HO-1, 32 kDa) is an inducible stress responsive protein, which possesses multiple functions in many cellular processes. In the current study, we identified a novel alternative splice isoform of 14 kDa HO-1 generated through exclusion of exon 3, and it is highly expressed in immortalized cells. In contrast to nuclear accumulation of the full-length 32 kDa HO-1, the novel 14 kDa HO-1 isoform is retained in the cytoplasm under ultraviolet (UV) irradiation. Interestingly, the 14 kDa HO-1 is shown to promote cell proliferation and an increase in relative telomere lengths in vivo and in vitro. Thus, we are pioneer to report and confirm the presence of a novel splice form of HO-1 and its distinct role in modulating telomere length and tumor growth.
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Affiliation(s)
- Chunxiang Bian
- The Base of "111 Project" for Biomechanics & Tissue Repair Engineering, Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering college, Life Science College, Chongqing University, Chongqing, 400044, China
| | - Maojiao Zhong
- The Base of "111 Project" for Biomechanics & Tissue Repair Engineering, Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering college, Life Science College, Chongqing University, Chongqing, 400044, China
| | - Muhammad Farrukh Nisar
- The Base of "111 Project" for Biomechanics & Tissue Repair Engineering, Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering college, Life Science College, Chongqing University, Chongqing, 400044, China; Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS Institute of Information Technology, Lahore, 54000, Pakistan
| | - Yan Wu
- The Base of "111 Project" for Biomechanics & Tissue Repair Engineering, Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering college, Life Science College, Chongqing University, Chongqing, 400044, China
| | - Mingyue Ouyang
- The Base of "111 Project" for Biomechanics & Tissue Repair Engineering, Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering college, Life Science College, Chongqing University, Chongqing, 400044, China
| | - Jörg W Bartsch
- Department of Neurosurgery, Philipps-University Marburg, Baldingerstr., 35033, Marburg, Germany
| | - Julia Li Zhong
- The Base of "111 Project" for Biomechanics & Tissue Repair Engineering, Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering college, Life Science College, Chongqing University, Chongqing, 400044, China.
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Li G, Shen J, Cao J, Zhou G, Lei T, Sun Y, Gao H, Ding Y, Xu W, Zhan Z, Chen Y, Huang H. Alternative splicing of human telomerase reverse transcriptase in gliomas and its modulation mediated by CX-5461. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2018; 37:78. [PMID: 29631594 PMCID: PMC5891986 DOI: 10.1186/s13046-018-0749-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/02/2018] [Indexed: 02/08/2023]
Abstract
Background Glioma is a heterogeneous, invasive primary brain tumor with a wide range of patient survival and a lack of reliable prognostic biomarkers. Human telomerase reverse transcriptase (hTERT) has been reported in the presence of multiple transcripts in various tumor systems. The biological function and precise regulatory mechanisms of hTERT transcripts remain uncertain. Methods Alternative splicing of hTERT and telomerase activity were examined in 96 glioma specimens, including 38 glioblastomas (GBMs), 23 oligodendrogliomas (ODMs), and 35 oligoastrocytomas (OAMs). The correlation between telomerase activity or hTERT transcripts and patient clinical characteristics was investigated. We examined the regulation of alternative splicing of hTERT and telomerase activity by G-quadruplex stabilizer CX-5461 in GBM cells. The biological effects of CX-5461 on GBM cell lines, including inhibition of cell proliferation, effects on cell cycle/apoptosis, and telomere DNA damage were further explored. Results The β splicing was verified in human gliomas and hTERT+β was significantly correlated with higher telomerase activity, higher KPS, larger tumor size, and higher tumor grades. Meanwhile, glioma patients lacking hTERT+β expression or telomerase activity showed a significant survival benefit. Notably, CX-5461 altered hTERT splicing patterns, leading to an increase of hTERT-β transcript and a decrease of hTERT+β transcript expression, which inhibits telomerase activity. In addition, CX-5461 had cytotoxic effects on GBM cells and caused telomere DNA damage response, induced G2/M arrest and apoptosis. Conclusions The hTERT+β is verified to be correlated with clinical parameters in gliomas, and could serve as a prognostic marker or possibly therapeutic target for gliomas. CX-5461 can regulate the splicing pattern of hTERT, inhibit telomerase activity, and kill GBM cells.
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Affiliation(s)
- Guihong Li
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, 130021, China.,Department of Neurosurgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, China
| | - Jing Shen
- Department of Cardiology, Shengze Hospital of Jiangsu Province, Suzhou, 215200, China
| | - Junguo Cao
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, 130021, China
| | - Guangtong Zhou
- Department of Neurosurgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, China
| | - Ting Lei
- Department of Neurovascular Research Laboratory and Neuroscience, Universitat Autonoma de Barcelona, 08035, Barcelona, Spain
| | - Yuxue Sun
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, 130021, China
| | - Haijun Gao
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, 130021, China
| | - Yaonan Ding
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, 130021, China
| | - Weidong Xu
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, 130021, China
| | - Zhixin Zhan
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, 130021, China
| | - Yong Chen
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, 130021, China.
| | - Haiyan Huang
- Department of Neurosurgery, First Hospital of Jilin University, Changchun, 130021, China.
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Dong W, Wu L, Sun H, Ren X, Epling-Burnette PK, Yang L. MDS shows a higher expression of hTERT and alternative splice variants in unactivated T-cells. Oncotarget 2018; 7:71904-71914. [PMID: 27655690 PMCID: PMC5342131 DOI: 10.18632/oncotarget.12115] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/10/2016] [Indexed: 12/19/2022] Open
Abstract
Telomere instability and telomerase reactivation are believed to play an important role in the development of myelodysplastic syndromes (MDS). Abnormal enzymatic activity of human telomerase reverse transcriptase (hTERT), and its alternative splice variants have been reported to account for deregulated telomerase function in many cancers. In this study, we aim to compare the differences in expression of hTERT and hTERT splice variants, as well as telomere length and telomerase activity in unstimulated T-cells between MDS subgroups and healthy controls. Telomere length in MDS cases was significantly shorter than controls (n = 20, p<0.001) and observed across all subtypes of MDS using World Health Organization classification (WHO subgroups versus control: RARS, p= 0.009; RCMD, p=0.0002; RAEB1/2, p=0.004, respectively) and the International Prognostic Scoring System (IPSS subgroups: Low+Int-1, p<0.001; Int-2+High, p=0.004). However, unstimulated T-cells from MDS patients (n=20) had significantly higher telomerase activity (p=0.002), higher total hTERT mRNA levels (p=0.001) and hTERT α+β- splice variant expression (p<0.001) compared to controls. Other hTERT splice variants were lower in expression and not significantly different among cases and controls. Telomerase activity was positively correlated with total hTERT levels in MDS (r=0.58, p=0.007). This data is in sharp contrast to data published previously by our group showing a reduction in telomerase and hTERT mRNA in MDS T-cells after activation. In conclusion, this study provides additional insight into hTERT transcript patterns and activity in peripheral T-cells of MDS patients. Additional studies are necessary to better understand the role of this pathway in MDS development and progression.
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Affiliation(s)
- Wen Dong
- Department of Orthopaedic Surgery, Tianjin Hongqiao Hospital, Tianjin, P.R. China
| | - Lei Wu
- Department of Immunology, Tianjin Cancer Institute and Hospital, Tianjin Medical University, P.R. China.,National Clinical Research Center of Cancer, P.R. China.,Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, P.R. China
| | - Houfang Sun
- Department of Immunology, Tianjin Cancer Institute and Hospital, Tianjin Medical University, P.R. China.,National Clinical Research Center of Cancer, P.R. China.,Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, P.R. China
| | - Xiubao Ren
- Department of Immunology, Tianjin Cancer Institute and Hospital, Tianjin Medical University, P.R. China.,National Clinical Research Center of Cancer, P.R. China.,Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, P.R. China
| | | | - Lili Yang
- Department of Immunology, Tianjin Cancer Institute and Hospital, Tianjin Medical University, P.R. China.,National Clinical Research Center of Cancer, P.R. China.,Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, P.R. China
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Liu X, Wang Y, Chang G, Wang F, Wang F, Geng X. Alternative Splicing of hTERT Pre-mRNA: A Potential Strategy for the Regulation of Telomerase Activity. Int J Mol Sci 2017; 18:ijms18030567. [PMID: 28272339 PMCID: PMC5372583 DOI: 10.3390/ijms18030567] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 02/14/2017] [Accepted: 03/02/2017] [Indexed: 12/11/2022] Open
Abstract
The activation of telomerase is one of the key events in the malignant transition of cells, and the expression of human telomerase reverse transcriptase (hTERT) is indispensable in the process of activating telomerase. The pre-mRNA alternative splicing of hTERT at the post-transcriptional level is one of the mechanisms for the regulation of telomerase activity. Shifts in splicing patterns occur in the development, tumorigenesis, and response to diverse stimuli in a tissue-specific and cell type–specific manner. Despite the regulation of telomerase activity, the alternative splicing of hTERT pre-mRNA may play a role in other cellular functions. Modulating the mode of hTERT pre-mRNA splicing is providing a new precept of therapy for cancer and aging-related diseases. This review focuses on the patterns of hTERT pre-mRNA alternative splicing and their biological functions, describes the potential association between the alternative splicing of hTERT pre-mRNA and telomerase activity, and discusses the possible significance of the alternative splicing of the hTERT pre-mRNA in the diagnosis, therapy, and prognosis of cancer and aging-related diseases.
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Affiliation(s)
- Xuewen Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China.
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin 300070, China.
| | - Yuchuan Wang
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin 300070, China.
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070, China.
| | - Guangming Chang
- Department of Clinical Laboratory, General Hospital, Tianjin Medical University, Tianjin 300070, China.
| | - Feng Wang
- Department of Genetics, Tianjin Medical University, Tianjin 300070, China.
| | - Fei Wang
- Department of Neurology, General Hospital, Tianjin Medical University, Tianjin 300052, China.
| | - Xin Geng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China.
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin 300070, China.
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Novak R, Hart K, Mathies RA. Single cell measurement of telomerase expression and splicing using microfluidic emulsion cultures. Nucleic Acids Res 2015. [PMID: 26202962 PMCID: PMC4652743 DOI: 10.1093/nar/gkv477] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Telomerase is a reverse transcriptase that maintains telomeres on the ends of chromosomes, allowing rapidly dividing cells to proliferate while avoiding senescence and apoptosis. Understanding telomerase gene expression and splicing at the single cell level could yield insights into the roles of telomerase during normal cell growth as well as cancer development. Here we use droplet-based single cell culture followed by single cell or colony transcript abundance analysis to investigate the relationship between cell growth and transcript abundance of the telomerase genes encoding the RNA component (hTR) and protein component (hTERT) as well as hTERT splicing. Jurkat and K562 cells were examined under normal cell culture conditions and during exposure to curcumin, a natural compound with anti-carcinogenic and telomerase activity-reducing properties. Individual cells predominantly express single hTERT splice variants, with the α+/β− variant exhibiting significant transcript abundance bimodality that is sustained through cell division. Sub-lethal curcumin exposure results in reduced bimodality of all hTERT splice variants and significant upregulation of alpha splicing, suggesting a possible role in cellular stress response. The single cell culture and transcript abundance analysis method presented here provides the tools necessary for multiparameter single cell analysis which will be critical for understanding phenotypes of heterogeneous cell populations, disease cell populations and their drug response.
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Affiliation(s)
- Richard Novak
- UCSF/UC Berkeley Graduate Program in Bioengineering, University of California, Berkeley, CA 94720, USA
| | - Kristina Hart
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Richard A Mathies
- UCSF/UC Berkeley Graduate Program in Bioengineering, University of California, Berkeley, CA 94720, USA Department of Chemistry, University of California, Berkeley, CA 94720, USA
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Wei YB, Backlund L, Wegener G, Mathé AA, Lavebratt C. Telomerase dysregulation in the hippocampus of a rat model of depression: normalization by lithium. Int J Neuropsychopharmacol 2015; 18:pyv002. [PMID: 25618407 PMCID: PMC4540104 DOI: 10.1093/ijnp/pyv002] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 01/05/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Telomeres are protective DNA-protein complexes at the ends of each chromosome, maintained primarily by the enzyme telomerase. Shortening of the blood leukocyte telomeres is associated with aging, several chronic diseases, and stress, eg, major depression. Hippocampus is pivotal in the regulation of cognition and mood and the main brain region of telomerase activity. Whether there is telomere dysfunction in the hippocampus of depressed subjects is unknown. Lithium, used in the treatment and relapse prevention of mood disorders, was found to protect against leukocyte telomere shortening in humans, but the mechanism has not been elucidated. To answer the questions whether telomeres are shortened and the telomerase activity changed in the hippocampus and whether lithium could reverse the process, we used a genetic model of depression, the Flinders Sensitive Line rat, and treated the animals with lithium. METHODS Telomere length, telomerase reverse transcriptase (Tert) expression, telomerase activity, and putative mediators of telomerase activity were investigated in the hippocampus of these animals. RESULTS The naïve Flinders Sensitive Line had shorter telomere length, downregulated Tert expression, reduced brain-derived neurotrophic factor levels, and reduced telomerase activity compared with the Flinders Resistant Line controls. Lithium treatment normalized the Tert expression and telomerase activity in the Flinders Sensitive Line and upregulated β-catenin. CONCLUSION This is the first report showing telomere dysregulation in hippocampus of a well-defined depression model and restorative effects of lithium treatment. If replicated in other models of mood disorder, the findings will contribute to understanding both the telomere function and the mechanism of lithium action in hippocampus of depressed patients.
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Hosen I, Rachakonda PS, Heidenreich B, Sitaram RT, Ljungberg B, Roos G, Hemminki K, Kumar R. TERT promoter mutations in clear cell renal cell carcinoma. Int J Cancer 2014; 136:2448-52. [PMID: 25331263 DOI: 10.1002/ijc.29279] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 10/07/2014] [Indexed: 01/22/2023]
Abstract
We screened promoter region of the telomerase reverse transcriptase (TERT) for activating somatic mutations in 188 tumors from patients with clear cell renal cell carcinoma (ccRCC). Twelve tumors (6.4%) carried a mutation within the core promoter region of the gene. The mutations were less frequent in high grade tumors compared to low grade tumors [odds ratio (OR) = 0.15, 95% confidence interval (CI) = 0.03-0.72, p = 0.02]. Multivariate analysis for cause specific survival showed statistically significant poor outcome in patients with TERT promoter mutations [hazard ratio (HR) = 2.90, 95% CI = 1.13-7.39, p = 0.03]. A common polymorphism (rs2853669) within the locus seemed to act as a modifier of the effect of the mutations on patient survival as the noncarriers of the variant allele with the TERT promoter mutations showed worst survival (HR = 3.34, 95% CI = 1.24-8.98, p = 0.02). We also measured relative telomere length (RTL) in tumors and difference between tumors with and without the TERT promoter mutations was not statistically significant. Similarly, no difference in patient survival based on RTL in tumors was observed. Our study showed a relatively low frequency of TERT promoter mutations in ccRCC. Nevertheless, patients with the mutations, particularly in the absence of the rs2853669 variant showed the worst disease-specific survival. Thus, it is possible that the TERT promoter mutations define a small subset of tumors with an aggressive behavior.
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Affiliation(s)
- Ismail Hosen
- Division of Molecular Genetic Epidemiology, German Cancer Research Center, Heidelberg, Germany
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Inactive C-terminal telomerase reverse transcriptase insertion splicing variants are dominant-negative inhibitors of telomerase. Biochimie 2014; 101:93-103. [DOI: 10.1016/j.biochi.2013.12.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 12/30/2013] [Indexed: 12/12/2022]
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