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Lee SE, Lee SB, Roh JI, Kim KP, Lee JH, Lee HW. SIRT1 regulates the localization and stability of telomerase protein by direct interaction. Biochem Biophys Res Commun 2024; 720:150098. [PMID: 38749190 DOI: 10.1016/j.bbrc.2024.150098] [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: 03/31/2024] [Revised: 05/06/2024] [Accepted: 05/09/2024] [Indexed: 06/05/2024]
Abstract
Telomerase reverse transcriptase (TERT) not only upholds telomeric equilibrium but also plays a pivotal role in multiple non-canonical cellular mechanisms, particularly in the context of aging, cancer, and genomic stability. Though depletion of SIRT1 in mouse embryonic fibroblasts has demonstrated telomere shortening, the impact of SIRT1 on enabling TERT to regulate telomeric homeostasis remains enigmatic. Here, we reveal that SIRT1 directly interacts with TERT, and promotes the nuclear localization and stability of TERT. Reverse transcriptase (RT) domain of TERT and N-terminus of SIRT1 mainly participated in their direct interaction. TERT, concomitantly expressed with intact SIRT1, exhibits nuclear localization, whereas TERT co-expressed with N-terminal-deleted SIRT1 remains in the cytosol. Furthermore, overexpression of SIRT1 enhances the nuclear localization and protein stability of TERT, akin to overexpression of deacetylase-inactive SIRT1, whereas N-terminal-deleted SIRT1 has no effect on TERT. These findings suggest a novel regulatory role of SIRT1 for TERT through direct interaction. This interaction provides new insights into the fields of aging, cancer, and genome stability governed by TERT and SIRT1.
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Affiliation(s)
- Seung Eon Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Su Bin Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Jae-Il Roh
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea; ReCerise Therapeutics Inc., 400-12, Yangcheon-ro, Gangseo-gu, Seoul, 07573, Republic of Korea
| | - Kwang Pyo Kim
- Department of Applied Chemistry, Institute of Natural Science, Global Center for Pharmaceutical Ingredient Materials, Kyung Hee University, Yongin-si, 17104, Gyeonggi-do, Republic of Korea
| | - Jae Hoon Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea; GEMCRO, Inc., Seoul, 03722, Republic of Korea.
| | - Han-Woong Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea; GEMCRO, Inc., Seoul, 03722, Republic of Korea.
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2
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Morozov A, Potoldykova N, Chinenov D, Enikeev M, Glukhov A, Shpikina A, Goryacheva E, Taratkin M, Malavaud B, Enikeev D. hTERT, hTR and TERT promoter mutations as markers for urological cancers detection: A systematic review. Urol Oncol 2021; 39:498.e21-498.e33. [PMID: 33676848 DOI: 10.1016/j.urolonc.2021.01.022] [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: 11/23/2020] [Revised: 01/14/2021] [Accepted: 01/18/2021] [Indexed: 12/30/2022]
Abstract
The clinical relevance of telomerase subunits (human reverse transcriptase - hTERT, and human telomerase RNA - hTR) and TERT promotor mutations as biomarkers in genitourinary cancers was reviewed through the systematic analysis of the current literature. We performed a systematic literature search using 2 databases (Medline and Scopus) over the past 20 years. Primary outcomes were sensitivity and specificity of hTR, hTERT and TERT promoter mutations. Secondary outcomes were the biomarkers predictive values for tumor characteristics. Regarding bladder cancer, hTERT in urine showed high sensitivity (mean values: 55%-96%), and specificity (69%-100%): it correlated with bladder cancer grade and/or stage. hTR sensitivity ranged from 77% to 92%. With adapted cut-off, it demonstrated 72% to 89% specificity. TERT promoter mutation rate was up to 80% both in tissue and urine, resulting in 62%-92% sensitivity for primary tumors and 42% for relapse. Specificity ranged from 73% to 96%, no correlations with stage were observed. In prostate cancer, hTERT in tissue, prostate secretion and serum showed high sensitivity (97.9%, 36%, and 79.2%-97.5%, respectively) and specificity values (70%, 66%, 60%-100%). hTR showed very high sensitivity (88% in serum and 100% in tissue) although specificity values were highly variable depending on the series and techniques (0%-96.5%). In RCC, hTERT sensitivity on tissue ranged from 90 to 97%, specificity from 25 to 58%. There was an association of hTERT expression with tumor stage and grade. hTERT showed high accuracy in genitourinary cancers, while the value of hTR was more controversial. hTERT and TERT promotor mutations may have predictive value for bladder cancer and RCC staging and grading, while no such relationship was observed in CaP. Although telomerase subunits showed clinically relevant values in genitourinary cancers, developing fast and cost-effective methods is required before contemplating routine use.
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Affiliation(s)
- Andrey Morozov
- Institute for Urology and Reproductive Health, Sechenov University, Moscow, Russia
| | - Natalya Potoldykova
- Institute for Urology and Reproductive Health, Sechenov University, Moscow, Russia
| | - Denis Chinenov
- Institute for Urology and Reproductive Health, Sechenov University, Moscow, Russia
| | - Mikhail Enikeev
- Institute for Urology and Reproductive Health, Sechenov University, Moscow, Russia
| | - Alexander Glukhov
- Sechenov University, Department of Biochemistry, Moscow, Russia; Lomonosov Moscow State University, Faculty of Biology, Moscow, Russia
| | | | | | - Mark Taratkin
- Institute for Urology and Reproductive Health, Sechenov University, Moscow, Russia
| | - Bernard Malavaud
- Department of Urology, Institut Universitaire du Cancer, Toulouse, France
| | - Dmitry Enikeev
- Institute for Urology and Reproductive Health, Sechenov University, Moscow, Russia.
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3
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Koroleva AG, Evtushenko EV, Vershinin AV, Zaytseva EP, Timoshkin OA, Kirilchik SV. Age Dynamics of Telomere Length in Endemic Baikal Planarians. Mol Biol 2020. [DOI: 10.1134/s002689332004007x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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La SH, Kim SJ, Kang HG, Lee HW, Chun KH. Ablation of human telomerase reverse transcriptase (hTERT) induces cellular senescence in gastric cancer through a galectin-3 dependent mechanism. Oncotarget 2016; 7:57117-57130. [PMID: 27494887 PMCID: PMC5302977 DOI: 10.18632/oncotarget.10986] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 07/19/2016] [Indexed: 12/20/2022] Open
Abstract
The human Telomerase Reverse Transcriptase (hTERT) gene encodes a rate-limiting catalytic subunit of telomerase that maintains genomic integrity. Suppression of hTERT expression could induce cellular senescence and is considered a potent approach for gastric cancer therapy. However, control of hTERT expression and function remains poorly understood in gastric cancer. In this study, we demonstrated that high expression levels of hTERT in malignant tissues are correlated with poor survival probability in gastric cancer patients. Knockdown of hTERT expression retarded cell proliferation and cellular senescence, which was confirmed by increased protein expression levels of p21cip1 and p27kip1, and decreased phosphorylation of Rb. In contrast, overexpression of hTERT increased cell proliferation and decreased cellular senescence. Remarkably, the down-regulation of hTERT expression was detected in lgals3-/- mouse embryo fibroblasts (MEFs). Knockdown of galectin-3 decreased the expression of hTERT in gastric cancer cells. Galectin-3 ablation-induced cellular senescence was rescued by concomitant overexpression of hTERT. hTERT ablation-induced cellular senescence and p21cip1 and p27kip1 expression was rescued by concomitant overexpression of galectin-3. The size of tumor burdens was increased in hTERT-overexpressed gastric cancer cells xenografted mice, whereas it was repressed by concomitant depletion of galectin-3. Additionally, we determined that the N-terminal domain of galectin-3 directly interacted with hTERT. The telomeric activity of hTERT was also decreased by galectin-3 ablation. Taken together, ablation of hTERT induces cellular senescence and inhibits the growth of gastric cancer cells, suggesting that it could be a potent target in gastric cancer therapy. We also propose that galectin-3 is an important regulator of hTERT expression and telomeric activity in gastric tumorigenesis.
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Affiliation(s)
- Sun-Hyuk La
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seodaemun-gu, Seoul 03722, Republic of Korea
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Seok-Jun Kim
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seodaemun-gu, Seoul 03722, Republic of Korea
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Hyeok-Gu Kang
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seodaemun-gu, Seoul 03722, Republic of Korea
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Han-Woong Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Kyung-Hee Chun
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seodaemun-gu, Seoul 03722, Republic of Korea
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seodaemun-gu, Seoul 03722, Republic of Korea
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5
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Zhang X, Cheng R, Shi Z, Jin Y. A PCR-free fluorescence strategy for detecting telomerase activity via double amplification strategy. Biosens Bioelectron 2015; 75:101-7. [PMID: 26299822 DOI: 10.1016/j.bios.2015.08.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 08/04/2015] [Accepted: 08/08/2015] [Indexed: 01/23/2023]
Abstract
As a universal tumor biomarker, research on the activity and inhibition of telomerase is of great importance for cancer diagnosis and therapy. Although the telomeric repeat amplification protocol (TRAP) has served as a powerful assay for detecting telomerase activity, its application has been significantly limited by amplification related errors and time-consuming procedure. To address the limitations of PCR-based protocol, a dual amplification fluorescence assay was developed for PCR-free detecting telomerase activity. Briefly, we designed an arch-structure DNA probe to specifically control strand displacement reaction and subsequent enzyme-aided amplification. Telomerase substrate (TS) primer was extended by telomerase to form long elongation products which contain several TTAGGG repeat units. So, one elongation product can release more than one trigger DNA (t-DNA) via strand displacement reaction to realize first amplification. Subsequently, t-DNA specifically opened molecular beacon (MB) to restore the fluorescence of MB. Meanwhile, t-DNA was recycled by the aid of nicking endonuclease to continuously open more and more MBs, leading to a second amplification. Owing to the double amplification strategy, the proposed method allowed the measurement of telomerase activity in crude cell extracts equivalent to 5 HeLa cells and 10 CCRF-CEM cells without PCR amplification. Besides, the influence of telomere-binding ligands on the telomerase activity demonstrated that the proposed method holds the potential to evaluate the inhibition efficiency of telomerase inhibitors.
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Affiliation(s)
- Xiafei Zhang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China
| | - Rui Cheng
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China
| | - Zhilu Shi
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China
| | - Yan Jin
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China.
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6
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Bautista-España D, Anastacio-Marcelino E, Horta-Valerdi G, Celestino-Montes A, Kojic M, Negrete-Abascal E, Reyes-Cervantes H, Vázquez-Cruz C, Guzmán P, Sánchez-Alonso P. The telomerase reverse transcriptase subunit from the dimorphic fungus Ustilago maydis. PLoS One 2014; 9:e109981. [PMID: 25299159 PMCID: PMC4192592 DOI: 10.1371/journal.pone.0109981] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 09/15/2014] [Indexed: 01/11/2023] Open
Abstract
In this study, we investigated the reverse transcriptase subunit of telomerase in the dimorphic fungus Ustilago maydis. This protein (Trt1) contains 1371 amino acids and all of the characteristic TERT motifs. Mutants created by disrupting trt1 had senescent traits, such as delayed growth, low replicative potential, and reduced survival, that were reminiscent of the traits observed in est2 budding yeast mutants. Telomerase activity was observed in wild-type fungus sporidia but not those of the disruption mutant. The introduction of a self-replicating plasmid expressing Trt1 into the mutant strain restored growth proficiency and replicative potential. Analyses of trt1 crosses in planta suggested that Trt1 is necessary for teliospore formation in homozygous disrupted diploids and that telomerase is haploinsufficient in heterozygous diploids. Additionally, terminal restriction fragment analysis in the progeny hinted at alternative survival mechanisms similar to those of budding yeast.
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Affiliation(s)
- Dolores Bautista-España
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, Mexico
| | - Estela Anastacio-Marcelino
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, Mexico
| | - Guillermo Horta-Valerdi
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, Mexico
| | - Antonio Celestino-Montes
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, Mexico
| | - Milorad Kojic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Erasmo Negrete-Abascal
- Facultad de Estudios Superiores Iztacala, UNAM, Los Reyes Iztacala, Tlalnepantla, Estado de Mexico, Mexico
| | - Hortensia Reyes-Cervantes
- Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, Mexico
| | - Candelario Vázquez-Cruz
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, Mexico
| | - Plinio Guzmán
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Irapuato, Guanajuato, Mexico
| | - Patricia Sánchez-Alonso
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Puebla, Mexico
- * E-mail:
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7
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Chen L, Huang J, Meng F, Zhou N. Distinguishing tumor cells via analyzing intracellular telomerase activity. ANAL SCI 2010; 26:535-8. [PMID: 20467126 DOI: 10.2116/analsci.26.535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Two strategies to identify tumor cells were developed in this research via analyzing the activity of telomerase inside the cells, which is regarded as the mark enzyme of tumors. The lysate of cells was used to assay directly. In the electrochemical assay, the substrate of telomerase was incubated with the lysate, followed by PCR amplification of the elongated products. Then the oxidation peak current of guanine that existed in the hydrolyte of PCR products was used as a target to identify tumor cells. In the spectral assay, the lysate of cells was used to catalyze the elongation of the substrate of telomerase modified on the surface of gold nanoparticles. Due to the formation of G-quadruple structures after elongation and subsequent aggregation of gold nanoparticles, the changes in UV-visible spectra can also be utilized to identify tumor cells.
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Affiliation(s)
- Lin Chen
- Laboratory of Biosensing Technology, School of Life Science, Shanghai University, Shanghai 200444, P. R. China
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8
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Oh W, Lee EW, Lee D, Yang MR, Ko A, Yoon CH, Lee HW, Bae YS, Choi CY, Song J. Hdm2 negatively regulates telomerase activity by functioning as an E3 ligase of hTERT. Oncogene 2010; 29:4101-12. [PMID: 20453884 DOI: 10.1038/onc.2010.160] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In this study, we identified posttranslational regulation of human telomerase reverse-transcriptase (hTERT) by the E3 ligase Hdm2. The telomerase activity generated by exogenous hTERT in U2OS cells was reduced on adriamycin treatment. The overexpressed levels of hTERT were also decreased under the same conditions. These processes were reversed by treatment with a proteasome inhibitor or depletion of Hdm2. Furthermore, intrinsic telomerase activity was increased in HCT116 cells with ablation of Hdm2. Immunoprecipitation analyses showed that hTERT and Hdm2 bound to each other in multiple domains. Ubiquitination analyses showed that Hdm2 could polyubiquitinate hTERT principally at the N-terminus, which was further degraded in a proteasome-dependent manner. An hTERT mutant with all five lysine residues at the N-terminus of hTERT that mutated to arginine became resistant to Hdm2-mediated ubiquitination and degradation. In U2OS cells, depletion of Hdm2 or addition of the Hdm2-resistant hTERT mutant strengthened the cellular protective effects against apoptosis. Similar results were obtained with the Hdm2-stable H1299 cell line. These observations indicate that Hdm2 is an E3 ligase of hTERT.
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Affiliation(s)
- W Oh
- Department of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon, Korea
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9
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Telomere-centromere-driven genomic instability contributes to karyotype evolution in a mouse model of melanoma. Neoplasia 2010; 12:11-9. [PMID: 20072649 DOI: 10.1593/neo.91004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2009] [Revised: 09/20/2009] [Accepted: 09/22/2009] [Indexed: 12/28/2022] Open
Abstract
Aneuploidy and chromosomal instability (CIN) are hallmarks of most solid tumors. These alterations may result from inaccurate chromosomal segregation during mitosis, which can occur through several mechanisms including defective telomere metabolism, centrosome amplification, dysfunctional centromeres, and/or defective spindle checkpoint control. In this work, we used an in vitro murine melanoma model that uses a cellular adhesion blockade as a transforming factor to characterize telomeric and centromeric alterations that accompany melanocyte transformation. To study the timing of the occurrence of telomere shortening in this transformation model, we analyzed the profile of telomere length by quantitative fluorescent in situ hybridization and found that telomere length significantly decreased as additional rounds of cell adhesion blockages were performed. Together with it, an increase in telomere-free ends and complex karyotypic aberrations were also found, which include Robertsonian fusions in 100% of metaphases of the metastatic melanoma cells. These findings are in agreement with the idea that telomere length abnormalities seem to be one of the earliest genetic alterations acquired in the multistep process of malignant transformation and that telomere abnormalities result in telomere aggregation, breakage-bridge-fusion cycles, and CIN. Another remarkable feature of this model is the abundance of centromeric instability manifested as centromere fragments and centromeric fusions. Taken together, our results illustrate for this melanoma model CIN with a structural signature of centromere breakage and telomeric loss.
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10
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Ding C, Li X, Ge Y, Zhang S. Fluorescence Detection of Telomerase Activity in Cancer Cells Based on Isothermal Circular Strand-Displacement Polymerization Reaction. Anal Chem 2010; 82:2850-5. [DOI: 10.1021/ac902818w] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Caifeng Ding
- Key Laboratory of Eco-chemical Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Xiangling Li
- Key Laboratory of Eco-chemical Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Ying Ge
- Key Laboratory of Eco-chemical Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Shusheng Zhang
- Key Laboratory of Eco-chemical Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
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11
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Oh W, Ghim J, Lee EW, Yang MR, Kim ET, Ahn JH, Song J. PML-IV functions as a negative regulator of telomerase by interacting with TERT. J Cell Sci 2009; 122:2613-22. [PMID: 19567472 DOI: 10.1242/jcs.048066] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Maintaining proper telomere length requires the presence of the telomerase enzyme. Here we show that telomerase reverse transcriptase (TERT), a catalytic component of telomerase, is recruited to promyelocytic leukemia (PML) nuclear bodies through its interaction with PML-IV. Treatment of interferon-alpha (IFNalpha) in H1299 cells resulted in the increase of PML proteins with a concurrent decrease of telomerase activity, as previously reported. PML depletion, however, stimulated telomerase activity that had been inhibited by IFNalpha with no changes in TERT mRNA levels. Upon treatment with IFNalpha, exogenous TERT localized to PML nuclear bodies and binding between TERT and PML increased. Immunoprecipitation and immunofluorescence analyses showed that TERT specifically bound to PML-IV. Residues 553-633 of the C-terminal region of PML-IV were required for its interaction with the TERT region spanning residues 1-350 and 595-946. The expression of PML-IV and its deletion mutant, 553-633, suppressed intrinsic telomerase activity in H1299. TERT-mediated immunoprecipitation of PML or the 553-633 fragment demonstrated that these interactions inhibited telomerase activity. H1299 cell lines stably expressing PML-IV displayed decreased telomerase activity with no change of TERT mRNA levels. Accordingly, telomere length of PML-IV stable cell lines was shortened. These results indicate that PML-IV is a negative regulator of telomerase in the post-translational state.
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Affiliation(s)
- Wonkyung Oh
- Department of Biotechnology and Bioengineering, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Korea
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12
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Rossi A, Russo G, Puca A, La Montagna R, Caputo M, Mattioli E, Lopez M, Giordano A, Pentimalli F. The antiretroviral nucleoside analogue Abacavir reduces cell growth and promotes differentiation of human medulloblastoma cells. Int J Cancer 2009; 125:235-43. [PMID: 19358275 DOI: 10.1002/ijc.24331] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Abacavir is one of the most efficacious nucleoside analogues, with a well-characterized inhibitory activity on reverse transcriptase enzymes of retroviral origin, and has been clinically approved for the treatment of AIDS. Recently, Abacavir has been shown to inhibit also the human telomerase activity. Telomerase activity seems to be required in essentially all tumours for the immortalization of a subset of cells, including cancer stem cells. In fact, many cancer cells are dependent on telomerase for their continued replication and therefore telomerase is an attractive target for cancer therapy. Telomerase expression is upregulated in primary primitive neuroectodermal tumours and in the majority of medulloblastomas suggesting that its activation is associated with the development of these diseases. Therefore, we decided to test Abacavir activity on human medulloblastoma cell lines with high telomerase activity. We report that exposure to Abacavir induces a dose-dependent decrease in the proliferation rate of medulloblastoma cells. This is associated with a cell accumulation in the G(2)/M phase of the cell cycle in the Daoy cell line, and with increased cell death in the D283-MED cell line, and is likely to be dependent on the inhibition of telomerase activity. Interestingly, both cell lines showed features of senescence after Abacavir treatment. Moreover, after Abacavir exposure we detected, by immunofluorescence staining, increased protein expression of the glial marker glial fibrillary acidic protein and the neuronal marker synaptophysin in both medulloblastoma cell lines. In conclusion, our results suggest that Abacavir reduces proliferation and induces differentiation of human medulloblastoma cells through the downregulation of telomerase activity. Thus, using Abacavir, alone or in combination with current therapies, might be an effective therapeutic strategy for the treatment of medulloblastoma.
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Affiliation(s)
- Alessandra Rossi
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia PA
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13
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14
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Eskiocak U, Ozkan-Ariksoysal D, Ozsoz M, Öktem HA. Label-Free Detection of Telomerase Activity Using Guanine Electrochemical Oxidation Signal. Anal Chem 2007; 79:8807-11. [DOI: 10.1021/ac071014r] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ugur Eskiocak
- Department of Biological Sciences, Middle East Technical University, 06531 Ankara, Turkey, and Department of Analytical Chemistry, Faculty of Pharmacy, Ege Univesity, 35100 Bornova-İzmir, Turkey
| | - Dilsat Ozkan-Ariksoysal
- Department of Biological Sciences, Middle East Technical University, 06531 Ankara, Turkey, and Department of Analytical Chemistry, Faculty of Pharmacy, Ege Univesity, 35100 Bornova-İzmir, Turkey
| | - Mehmet Ozsoz
- Department of Biological Sciences, Middle East Technical University, 06531 Ankara, Turkey, and Department of Analytical Chemistry, Faculty of Pharmacy, Ege Univesity, 35100 Bornova-İzmir, Turkey
| | - Huseyin Avni Öktem
- Department of Biological Sciences, Middle East Technical University, 06531 Ankara, Turkey, and Department of Analytical Chemistry, Faculty of Pharmacy, Ege Univesity, 35100 Bornova-İzmir, Turkey
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15
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Lin J, Jin R, Zhang B, Yang PX, Chen H, Bai YX, Xie Y, Huang C, Huang J. Characterization of a novel effect of hPinX1 on hTERT nucleolar localization. Biochem Biophys Res Commun 2007; 353:946-52. [PMID: 17198684 DOI: 10.1016/j.bbrc.2006.12.123] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Accepted: 12/14/2006] [Indexed: 11/21/2022]
Abstract
The factor PinX1 has been shown as a telomerase inhibitor evolutionarily conserved in both the yeast and the human being. yPinX1 inhibits telomerase activity by sequestering yTERT (telomerase reverse transcriptase) from uniting with yTR (telomerase template RNA) in the nucleolus of yeast cells. However, the mechanism underlying the action of hPinX1 on telomerase regulation in human cells is not known. We here demonstrated that hPinX1 actually has an effect on mediating hTERT nucleolar localization and this effect is mediated by a novel domain enclosed within the central section of the polypeptide. Interestingly, we showed that a reported cancerous mutant form of hPinX1, in which residues of Ser254 and Cys265 are, respectively, mutated to Cys and Tyr, lost the activity on mediating hTERT nucleolar localization. Finally, we provided evidence that mediation of hTERT nucleolar localization and telomerase enzymatic inhibition are two separated function of hPinX1 on telomerase regulation in human cells.
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Affiliation(s)
- Jian Lin
- Lab. Tumor and Molecular Biology, Beijing Institute of Biotechnology, 27 Taiping Road, Beijing, PR China
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Matsuo SE, Martins L, Leoni SG, Hajjar D, Ricarte-Filho JCM, Ebina KN, Kimura ET. Marcadores biológicos de tumores tiroidianos. ACTA ACUST UNITED AC 2004; 48:114-25. [PMID: 15611824 DOI: 10.1590/s0004-27302004000100013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Um marcador biológico ideal deve ser específico e sensível para identificar o tipo tumoral e caracterizar o estágio da progressão neoplásica. Os tumores de tiróide originam-se de dois tipos celulares: 1) carcinoma medular originário de células parafoliculares; e 2) as neoplasias de células epiteliais foliculares, que incluem bócio, adenomas, carcinomas diferenciados (carcinoma papilífero e carcinoma folicular) e carcinoma indiferenciado (carcinoma anaplásico). O comportamento biológico distinto faz com que cada tipo tumoral necessite de uma conduta terapêutica específica. O conhecimento acumulado ao longo destes anos, utilizando métodos de biologia molecular e, mais recentemente, a genômica, identificou mutações específicas de câncer de tiróide e, atualmente, entendemos muito das alterações que ocorrem na expressão de fatores de crescimento, seus receptores e proteínas sinalizadoras intracelular nas neoplasias tiroidianas. Contudo, apesar desses, até o momento não dispomos de um marcador eficiente que auxilie no diagnóstico e prognóstico e, conseqüentemente, para indicação de uma terapêutica mais adequada. Nesta revisão, discutiremos os principais aspectos relacionados à tumorigênese tiroidiana, avaliando o potencial destes fatores como marcador em neoplasia folicular de tiróide.
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Affiliation(s)
- Sílvia E Matsuo
- Departamento de Histologia & Embriologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP
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Nemos C, Rémy-Martin JP, Adami P, Arbez-Gindre F, Schaal JP, Jouvenot M, Delage-Mourroux R. Improved TRAP-silver staining versus conventional radioactive TRAP assays: quantification of telomerase activity during immortalization and in pathological human endometrium. Clin Biochem 2003; 36:621-8. [PMID: 14636877 DOI: 10.1016/s0009-9120(03)00111-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To develop a sensitive telomeric repeat amplification protocol (TRAP)-silver staining assay for telomerase activity quantification. DESIGN AND METHODS TRAP assays were performed by using a TRAPeze telomerase kit with or without [alpha-32P]-dCTP. Amplification products were electrophoresed in polyacrylamide gels and detected by autoradiography or a modified silver staining protocol. Telomerase activity was quantified from radioactive counts or optical density of telomerase products from test extracts and controls. RESULTS TRAP-silver staining assay was at least as sensitive as radioactive TRAP assay and quantified telomerase activity within linearity from 10 to 3,000 cell equivalents. Both methods quantified a weak telomerase activity in normal endometrial glandular epithelial cells (GEC) and a strong increase in immortalized GEC. In human pathologic endometria (n=24), telomerase activity was correlated with lesion seriousness and distinguished simple hyperplasias from nonhyperplasic or cancerous lesions. CONCLUSIONS TRAP-silver staining assay is suitable for cell and tissue telomerase activity routine quantification.
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Affiliation(s)
- C Nemos
- Laboratoire de Biochimie Biologie Moléculaire, Université de Franche-Comté, UFR Sciences et Techniques, Besançon, France
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18
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Rubiano CC, Wasserman M. Detection of telomerase activity in Plasmodium falciparum using a nonradioactive method. Mem Inst Oswaldo Cruz 2003; 98:693-5. [PMID: 12973539 DOI: 10.1590/s0074-02762003000500018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A simple, quick and sensitive method was used to detect telomerase activity in Plasmodium falciparum. The telomeric repeat amplification protocol (TRAP assay) was modified using electrophoresis and staining with SYBR-green I to detect telomerase activity in a range of 10 to 10(7) parasites. This might be a useful way to ascertain telomerase activity in different types of nontumor cells.
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Affiliation(s)
- Claudia C Rubiano
- Laboratorio Bioquímica, Instituto Nacional de Salud, Bogotá, Colombia
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