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Li S, Hu G, Chen Y, Sang Y, Tang Q, Liu R. TERT upstream promoter methylation regulates TERT expression and acts as a therapeutic target in TERT promoter mutation-negative thyroid cancer. Cancer Cell Int 2024; 24:271. [PMID: 39097722 PMCID: PMC11297792 DOI: 10.1186/s12935-024-03459-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 07/25/2024] [Indexed: 08/05/2024] Open
Abstract
BACKGROUND DNA hypermethylation and hotspot mutations were frequently observed in the upstream and core promoter of telomerase reverse transcriptase (TERT), respectively, and they were associated with increased TERT expression and adverse clinical outcomes in thyroid cancer. In TERT promoter mutant cancer cells, the hypomethylated TERT mutant allele was active and the hypermethylated TERT wild-type allele was silenced. However, whether and how the upstream promoter methylation regulates TERT expression in TERT mutation-negative cells were largely unknown. METHODS DNA demethylating agents 5-azacytidine and decitabine and a genomic locus-specific demethylation system based on dCas9-TET1 were used to assess the effects of TERT upstream promoter methylation on TERT expression, cell growth and apoptosis of thyroid cancer cells. Regulatory proteins binding to TERT promoter were identified by CRISPR affinity purification in situ of regulatory elements (CAPTURE) combined with mass spectrometry. The enrichments of selected regulatory proteins and histone modifications were evaluated by chromatin immunoprecipitation. RESULTS The level of DNA methylation at TERT upstream promoter and expression of TERT were significantly decreased after treatment with 5-azacytidine or decitabine in TERT promoter wild-type thyroid cancer cells. Genomic locus-specific demethylation of TERT upstream promoter induced TERT downregulation, along with cell apoptosis and growth inhibition. Consistently, demethylating agents sharply inhibited the growth of thyroid cancer cells harboring hypermethylated TERT but had little effect on cells with TERT hypomethylation. Moreover, we identified that the chromatin remodeling protein CHD4 binds to methylated TERT upstream promoter and promotes its transcription by suppressing the enrichment of H3K9me3 and H3K27me3 at TERT promoter. CONCLUSIONS This study uncovered the mechanism of promoter methylation mediated TERT activation in TERT promoter mutation-negative thyroid cancer cells and indicated TERT upstream promoter methylation as a therapeutic target for thyroid cancer.
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Affiliation(s)
- Shiyong Li
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan Second Road, Guangzhou, Guangdong, 510080, China
| | - Guanghui Hu
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan Second Road, Guangzhou, Guangdong, 510080, China
| | - Yulu Chen
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan Second Road, Guangzhou, Guangdong, 510080, China
| | - Ye Sang
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan Second Road, Guangzhou, Guangdong, 510080, China
| | - Qin Tang
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan Second Road, Guangzhou, Guangdong, 510080, China
| | - Rengyun Liu
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, No. 58, Zhongshan Second Road, Guangzhou, Guangdong, 510080, China.
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2
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Salmani-Javan E, Jafari-Gharabaghlou D, Bonabi E, Zarghami N. Fabricating niosomal-PEG nanoparticles co-loaded with metformin and silibinin for effective treatment of human lung cancer cells. Front Oncol 2023; 13:1193708. [PMID: 37664043 PMCID: PMC10471189 DOI: 10.3389/fonc.2023.1193708] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 07/13/2023] [Indexed: 09/05/2023] Open
Abstract
Background Despite current therapies, lung cancer remains a global issue and requires the creation of novel treatment methods. Recent research has shown that biguanides such as metformin (MET) and silibinin (SIL) have a potential anticancer effect. As a consequence, the effectiveness of MET and SIL in combination against lung cancer cells was investigated in this study to develop an effective and novel treatment method. Methods Niosomal nanoparticles were synthesized via the thin-film hydration method, and field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR), atomic force microscopy (AFM), and dynamic light scattering (DLS) techniques were used to evaluate their physico-chemical characteristics. The cytotoxic effects of free and drug-loaded nanoparticles (NPs), as well as their combination, on A549 cells were assessed using the MTT assay. An apoptosis test was used while under the influence of medication to identify the molecular mechanisms behind programmed cell death. With the use of a cell cycle test, it was determined whether pharmaceutical effects caused the cell cycle to stop progressing. Additionally, the qRT-PCR technique was used to evaluate the levels of hTERT, BAX, and BCL-2 gene expression after 48-h medication treatment. Results In the cytotoxicity assay, the growth of A549 lung cancer cells was inhibited by both MET and SIL. Compared to the individual therapies, the combination of MET and SIL dramatically and synergistically decreased the IC50 values of MET and SIL in lung cancer cells. Furthermore, the combination of MET and SIL produced lower IC50 values and a better anti-proliferative effect on A549 lung cancer cells. Real-time PCR results showed that the expression levels of hTERT and BCL-2 were significantly reduced in lung cancer cell lines treated with MET and SIL compared to single treatments (p< 0.001). Conclusion It is anticipated that the use of nano-niosomal-formed MET and SIL would improve lung cancer treatment outcomes and improve the therapeutic efficiency of lung cancer cells.
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Affiliation(s)
- Elnaz Salmani-Javan
- Department of Clinical Biochemistry and Laboratory Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Davoud Jafari-Gharabaghlou
- Department of Clinical Biochemistry and Laboratory Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Esat Bonabi
- Department of Medical Microbiology, Faculty of Medicine, Istanbul Aydin University, Istanbul, Türkiye
| | - Nosratollah Zarghami
- Department of Clinical Biochemistry and Laboratory Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Medical Biochemistry, Faculty of Medicine, Istanbul Aydin University, Istanbul, Türkiye
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3
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Ding H, Zhong Y, Liu N, Wu H, Xu H, Wu Y, Liu G, Yuan S, Zhou Q, Wang C. Panic disorder aging characteristics: The role of telomerase reverse transcriptase gene and brain function. Front Aging Neurosci 2022; 14:835963. [PMID: 35992589 PMCID: PMC9389410 DOI: 10.3389/fnagi.2022.835963] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 07/13/2022] [Indexed: 11/30/2022] Open
Abstract
Panic disorder (PD) causes serious functional damage and disability and accelerates the process of individual aging. The pathological basis of PD is the same as that of age-related diseases, which is proposed as a new viewpoint in recent years. Memory decline and social functional impairment are common manifestations of accelerated aging in PD. The function of telomerase reverse transcriptase (TERT) and telomere length (TL) is abnormal in patients with aging and PD. However, the molecular mechanism behind remains unclear. The purpose of this study was to explore the relationship between TERT gene expression (including DNA methylation) and the changes in PD aging characteristics (memory and social function). By TERT gene knockout mice, we found that loss of TERT attenuated the acquisition of recent fear memory during contextual fear conditioning. This study reported that a significantly lower methylation level of human TERT (hTERT) gene was detected in PD patients compared with healthy control and particularly decreased CpG methylation in the promoter region of hTERT was associated with the clinical characteristics in PD. Regional homogeneity (ReHo) analysis showed that the methylation of hTERT (cg1295648) influenced social function of PD patients through moderating the function of the left postcentral gyrus (PCG). This indicates that the hTERT gene may play an important role in the pathological basis of PD aging and may become a biological marker for evaluating PD aging. These findings provide multidimensional evidence for the underlying genetic and pathological mechanisms of PD.
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Affiliation(s)
- Huachen Ding
- Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, China
- Functional Brain Imaging Institute of Nanjing Medical University, Nanjing, China
| | - Yuan Zhong
- School of Psychology, Nanjing Normal University, Nanjing, China
| | - Na Liu
- Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, China
- Cognitive Behavioral Therapy Institute of Nanjing Medical University, Nanjing, China
| | - Huiqin Wu
- Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, China
- Functional Brain Imaging Institute of Nanjing Medical University, Nanjing, China
| | - Huazhen Xu
- Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, China
- Functional Brain Imaging Institute of Nanjing Medical University, Nanjing, China
| | - Yun Wu
- Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, China
- Functional Brain Imaging Institute of Nanjing Medical University, Nanjing, China
- School of Psychology, Nanjing Normal University, Nanjing, China
- Cognitive Behavioral Therapy Institute of Nanjing Medical University, Nanjing, China
| | - Gang Liu
- Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, China
- Functional Brain Imaging Institute of Nanjing Medical University, Nanjing, China
- Cognitive Behavioral Therapy Institute of Nanjing Medical University, Nanjing, China
| | - Shiting Yuan
- Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, China
- Functional Brain Imaging Institute of Nanjing Medical University, Nanjing, China
| | - Qigang Zhou
- Department of Clinical Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing, China
- Qigang Zhou,
| | - Chun Wang
- Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, China
- Functional Brain Imaging Institute of Nanjing Medical University, Nanjing, China
- School of Psychology, Nanjing Normal University, Nanjing, China
- Cognitive Behavioral Therapy Institute of Nanjing Medical University, Nanjing, China
- *Correspondence: Chun Wang,
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4
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Ricci C, Morandi L, Ambrosi F, Righi A, Gibertoni D, Maletta F, Agostinelli C, Corradini AG, Uccella S, Asioli S, Sessa F, La Rosa S, Papotti MG, Asioli S. Intron 4-5 hTERT DNA Hypermethylation in Merkel Cell Carcinoma: Frequency, Association with Other Clinico-pathological Features and Prognostic Relevance. Endocr Pathol 2021; 32:385-395. [PMID: 33909215 PMCID: PMC8370894 DOI: 10.1007/s12022-021-09669-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/15/2021] [Indexed: 12/23/2022]
Abstract
Merkel cell carcinoma (MCC) is an aggressive skin tumor with neuroendocrine differentiation, mainly affecting elderly population or immunocompromised individuals. As methylation of the human telomerase reverse transcriptase (mhTERT) has been shown to be a prognostic factor in different tumors, we investigated its role in MCC, in particular in intron 4-5 where rs10069690 has been mapped and recognized as a cancer susceptibility locus. DNA methylation analysis of hTERT gene was assessed retrospectively in a cohort of 69 MCC patients from the University of Bologna, University of Turin and University of Insubria. Overall mortality was evaluated with Kaplan-Meier curves and multivariable Royston-Parmar models. High levels of mhTERT (mhTERThigh) (HR = 2.500, p = 0.015) and p63 (HR = 2.659, p = 0.016) were the only two clinico-pathological features significantly associated with a higher overall mortality at the multivariate analysis. We did not find different levels of mhTERT between MCPyV (+) and (-) cases (21 vs 14, p = 0.554); furthermore, mhTERThigh was strongly associated with older age (80.5 vs 72 years, p = 0.026), no angioinvasion (40.7% vs 71.0%, p = 0.015), lower Ki67 (50 vs 70%, p = 0.005), and PD-L1 expressions in both tumor (0 vs 3%, p = 0.021) and immune cells (0 vs 10%, p = 0.002). mhTERT is a frequently involved epigenetic mechanism and a relevant prognostic factor in MCC. In addition, it belongs to the shared oncogenic pathways of MCC (MCPyV and UV-radiations) and it could be crucial, together with other epigenetic and genetic mechanisms as gene amplification, in determining the final levels of hTERT mRNA and telomerase activity in these patients.
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Affiliation(s)
- Costantino Ricci
- Pathology Unit, Maggiore Hospital, AUSL Bologna, Bologna, Italy
- Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, Bologna, Italy
| | - Luca Morandi
- Department of Biomedical and Neuromotor Sciences, Functional MR Unit, IRCCS Istituto delle Scienze Neurologiche, Bologna, Italy
| | | | - Alberto Righi
- Department of Pathology, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Dino Gibertoni
- Department of Biomedical and Neuromotor Sciences, Unit of Hygiene and Biostatistics, University of Bologna, Bologna, Italy
| | - Francesca Maletta
- Department of Oncology, University of Turin, Città Della Salute Hospital, Turin, Italy
| | - Claudio Agostinelli
- Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, Bologna, Italy
- Haematopathology Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Angelo Gianluca Corradini
- Department of Biomedical and Neuromotor Sciences, Functional MR Unit, IRCCS Istituto delle Scienze Neurologiche, Bologna, Italy
| | - Silvia Uccella
- Unit of Pathology, Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Silvia Asioli
- Unit of Pathology, Morgagni-Pierantoni Hospital, Forlì, 47121, Italy
| | - Fausto Sessa
- Unit of Pathology, Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Stefano La Rosa
- Institute of Pathology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Mauro Giulio Papotti
- Department of Oncology, University of Turin, Città Della Salute Hospital, Turin, Italy
| | - Sofia Asioli
- Department of Biomedical and Neuromotor Sciences (DIBINEM) Surgical Pathology Section- Alma Mater Studiorum , University of Bologna , Bologna, Italy.
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5
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Rauscher S, Greil R, Geisberger R. Re-Sensitizing Tumor Cells to Cancer Drugs with Epigenetic Regulators. Curr Cancer Drug Targets 2021; 21:353-359. [PMID: 33423645 DOI: 10.2174/1568009620666210108102723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/13/2020] [Accepted: 12/03/2020] [Indexed: 11/22/2022]
Abstract
Cancer drug resistance is a major problem for cancer therapy. While many drugs can be effective in first-line treatments, cancer cells can become resistant due to genetic (mutations and chromosomal aberrations) but also epigenetic changes. Hence, many research studies addressed epigenetic drugs in circumventing resistance to conventional therapeutics in different tumor entities and in increasing the efficiency of immune checkpoint therapies. Furthermore, repositioning of already approved drugs in combination with epigenetic modifiers could potentiate their efficacy and thus could be an attractive strategy for cancer treatment. Summarizing, we recapitulate current data on epigenetic drugs and their targets in modulating sensitivity towards conventional and immune therapies, providing evidence that altering expression profiles by epigenetic modifiers holds great potential to improve the clinical outcome of cancer patients.
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Affiliation(s)
- Stefanie Rauscher
- Department of Internal Medicine III with Haematology, Medical Oncology, Haemostaseology, Infectiology and Rheumatology, Oncologic Center, Salzburg Cancer Research Institute - Laboratory for Immunological and Molecular Cancer Research (SCRI-LIMCR), Paracelsus Medical University, Salzburg, Austria, Cancer Cluster Salzburg, 5020Salzburg, Austria
| | - Richard Greil
- Department of Internal Medicine III with Haematology, Medical Oncology, Haemostaseology, Infectiology and Rheumatology, Oncologic Center, Salzburg Cancer Research Institute - Laboratory for Immunological and Molecular Cancer Research (SCRI-LIMCR), Paracelsus Medical University, Salzburg, Austria, Cancer Cluster Salzburg, 5020Salzburg, Austria
| | - Roland Geisberger
- Department of Internal Medicine III with Haematology, Medical Oncology, Haemostaseology, Infectiology and Rheumatology, Oncologic Center, Salzburg Cancer Research Institute - Laboratory for Immunological and Molecular Cancer Research (SCRI-LIMCR), Paracelsus Medical University, Salzburg, Austria, Cancer Cluster Salzburg, 5020Salzburg, Austria
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6
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Garsuault D, Bouyer C, Nguyen E, Kandhari R, Prochazkova-Carlotti M, Chevret E, Forgez P, Ségal-Bendirdjian E. Complex context relationships between DNA methylation and accessibility, histone marks, and hTERT gene expression in acute promyelocytic leukemia cells: perspectives for all-trans retinoic acid in cancer therapy. Mol Oncol 2020; 14:1310-1326. [PMID: 32239597 PMCID: PMC7266276 DOI: 10.1002/1878-0261.12681] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/19/2020] [Accepted: 03/28/2020] [Indexed: 02/06/2023] Open
Abstract
Telomerase (hTERT) reactivation and sustained expression is a key event in the process of cellular transformation. Therefore, the identification of the mechanisms regulating hTERT expression is of great interest for the development of new anticancer therapies. Although the epigenetic state of hTERT gene promoter is important, we still lack a clear understanding of the mechanisms by which epigenetic changes affect hTERT expression. Retinoids are well-known inducers of granulocytic maturation in acute promyelocytic leukemia (APL). We have previously shown that retinoids repressed hTERT expression in the absence of maturation leading to growth arrest and cell death. Exploring the mechanisms of this repression, we showed that transcription factor binding was dependent on the epigenetic status of hTERT promoter. In the present study, we used APL cells lines and publicly available datasets from APL patients to further investigate the integrated epigenetic events that promote hTERT promoter transition from its silent to its active state, and inversely. We showed, in APL patients, that the methylation of the distal domain of hTERT core promoter was altered and correlated with the outcome of the disease. Further studies combining complementary approaches carried out on APL cell lines highlighted the significance of a domain outside the minimal promoter, localized around 5 kb upstream from the transcription start site, in activating hTERT. This domain is characterized by DNA hypomethylation and H3K4Me3 deposition. Our findings suggest a cooperative interplay between hTERT promoter methylation, chromatin accessibility, and histone modifications that force the revisiting of previously proposed concepts regarding hTERT epigenetic regulation. They represent, therefore, a major advance in predicting sensitivity to retinoid-induced hTERT repression and, more generally, in the potential development of therapies targeting hTERT expression in cancers.
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Affiliation(s)
- Delphine Garsuault
- Team: Cellular Homeostasis, Cancer, and Therapies, INSERM UMR-S 1124, Université de Paris, France.,Université de Paris, Paris Sorbonne Cité, France.,Paris-Sud University, Paris-Saclay University, Orsay, France
| | - Claire Bouyer
- Team: Cellular Homeostasis, Cancer, and Therapies, INSERM UMR-S 1124, Université de Paris, France.,Université de Paris, Paris Sorbonne Cité, France
| | - Eric Nguyen
- Team: Cellular Homeostasis, Cancer, and Therapies, INSERM UMR-S 1124, Université de Paris, France.,Université de Paris, Paris Sorbonne Cité, France
| | - Rohan Kandhari
- Team: Cellular Homeostasis, Cancer, and Therapies, INSERM UMR-S 1124, Université de Paris, France.,Indian Institute of Technology, BHU, Varanasi, India
| | | | - Edith Chevret
- Team Cutaneous Lymphoma Oncogenesis, INSERM U1053, Bordeaux, France
| | - Patricia Forgez
- Team: Cellular Homeostasis, Cancer, and Therapies, INSERM UMR-S 1124, Université de Paris, France.,Université de Paris, Paris Sorbonne Cité, France
| | - Evelyne Ségal-Bendirdjian
- Team: Cellular Homeostasis, Cancer, and Therapies, INSERM UMR-S 1124, Université de Paris, France.,Université de Paris, Paris Sorbonne Cité, France.,BioMedTech Facilities, CNRS UMS2009/INSERM US36, Université de Paris, France
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7
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The Solo Play of TERT Promoter Mutations. Cells 2020; 9:cells9030749. [PMID: 32204305 PMCID: PMC7140675 DOI: 10.3390/cells9030749] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/16/2020] [Accepted: 03/16/2020] [Indexed: 12/13/2022] Open
Abstract
The reactivation of telomerase reverse transcriptase (TERT) protein is the principal mechanism of telomere maintenance in cancer cells. Mutations in the TERT promoter (TERTp) are a common mechanism of TERT reactivation in many solid cancers, particularly those originating from slow-replicating tissues. They are associated with increased TERT levels, telomere stabilization, and cell immortalization and proliferation. Much effort has been invested in recent years in characterizing their prevalence in different cancers and their potential as biomarkers for tumor stratification, as well as assessing their molecular mechanism of action, but much remains to be understood. Notably, they appear late in cell transformation and are mutually exclusive with each other as well as with other telomere maintenance mechanisms, indicative of overlapping selective advantages and of a strict regulation of TERT expression levels. In this review, we summarized the latest literature on the role and prevalence of TERTp mutations across different cancer types, highlighting their biased distribution. We then discussed the need to maintain TERT levels at sufficient levels to immortalize cells and promote proliferation while remaining within cell sustainability levels. A better understanding of TERT regulation is crucial when considering its use as a possible target in antitumor strategies.
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8
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Yuan T, Zhao W, Niu Y, Fu Y, Lu L, Niu D. Exploration of the temporal-spatial expression pattern and DNA methylation-related regulation of the duck telomerase reverse transcriptase gene. Poult Sci 2019; 98:3257-3267. [PMID: 31064004 DOI: 10.3382/ps/pez240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 04/09/2019] [Indexed: 12/14/2022] Open
Abstract
Telomerase reverse transcriptase (TERT) is a catalytic subunit of telomerase that adds TTAGGG repeats to the 3'-overhang of telomeres. In the present study, we detected that the duck TERT (dTERT) gene was highly expressed in small intestine and kidney, followed by heart, leg muscle, spleen, pancreas, gonad, and liver at neonatal stage. From embryonic to neonatal stage, the highest dTERT mRNA in liver appeared at stage E19 (19 days at embryonic stage), while for the leg muscle the maximum expression occurred at E26. We also measured the relative telomerase activity (RTA) and relative telomere length (RTL) in the examined tissues and found that the changed tendency of RTA and RTL was not very consistent with that of TERT. In silico analysis revealed that there were three CpG islands (S1, S2, and S3) within the 5' regulatory region of the dTERT gene. Bisulfite sequencing PCR (BSP) assay showed that liver (D7, 7 days after birth) which expressed significantly lower dTERT mRNA had an obviously higher methylation level of S1 compared with small intestine (D7) or liver (E19). Quantitative real-time PCR analysis revealed that the expression of DNA methyltransferase DNMT1 in liver (D7) was significantly higher than that in small intestine (D7) or in liver (E19). In vitro, dTERT expression was upregulated and the methylation status of S1 decreased in both duck embryonic fibroblasts and small intestinal epithelial cells following treatment with the demethylation reagent, 5-aza-2'-deoxycytidine (5-aza-dC), further suggesting that dTERT is epigenetically regulated by DNA methylation. This work lays a solid foundation for further study of TERT function and regulation in avian species.
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Affiliation(s)
- Taoyan Yuan
- College of Animal Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.,Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, 145 Shiqiao Road, Hangzhou 310021, China
| | - Wanqiu Zhao
- College of Animal Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.,Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, 145 Shiqiao Road, Hangzhou 310021, China
| | - Yifan Niu
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan, China
| | - Yan Fu
- College of Animal Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Lizhi Lu
- Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, 145 Shiqiao Road, Hangzhou 310021, China.,Key Laboratory of Information Traceability for Agricultural Products, Ministry of Agriculture of China, Hangzhou 310021, Zhejiang, China
| | - Dong Niu
- College of Animal Science and Technology, Zhejiang A&F University
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9
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Xin Y, Dong K, Cao F, Tian Y, Sun J, Peng M, Liu W, Shi P. Studies of hTERT DNA methylation assays on the human age prediction. Int J Legal Med 2019; 133:1333-1339. [PMID: 31165262 DOI: 10.1007/s00414-019-02076-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 05/17/2019] [Indexed: 11/25/2022]
Abstract
As an important aspect of epigenetics, DNA methylation has been proven to be suitable for forensic DNA analysis. By detecting changes in DNA methylation, it is desirable to construct a model of age patterns associated with it to infer the age of the individual. The hTERT gene methylation is closely related to tumors, but there are few reports on the relationship between hTERT gene promoter methylation and age. In this study, we utilized the methylation-specific polymerase chain reaction and real-time PCR (relative quantification and absolute quantification) approach to explore the connection between hTERT DNA methylation and age prediction. We fit three models for age prediction based on methylation assay for 90 blood samples from donors aged 1-79 years old. Among them, the model of absolute quantification of real-time enabled the age prediction with R2 = 0.9634. We verified the linear regression model with a validation set of 30 blood samples where prediction average error was 4.29 years. Generally, this reliable method improves the DNA methylation analysis of forensic samples.
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Affiliation(s)
- Ye Xin
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Kaikai Dong
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Fangqi Cao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
- Shanghai Key Laboratory of Crime Scene Evidence, Shanghai Research Institute of Criminal Science and Technology, Zhongshan North No 1 Road, Shanghai, 200083, China
| | - Yuxiang Tian
- Department of Clinical Laboratory, Shanghai Xuhui District Dahua Hospital, Shanghai, 200237, China
| | - Jing Sun
- Qinghai Provincial Key Laboratory of Qinghai-Tibet Plateau Biological Resources, Northwest Institute of Plateau Biology, The Chinese Academy of Sciences, Xiguan Avenue 59, Xining, 11 Qinghai Province, 810001, China
| | - Min Peng
- Qinghai Provincial Key Laboratory of Qinghai-Tibet Plateau Biological Resources, Northwest Institute of Plateau Biology, The Chinese Academy of Sciences, Xiguan Avenue 59, Xining, 11 Qinghai Province, 810001, China
| | - Wenbin Liu
- Shanghai Key Laboratory of Crime Scene Evidence, Shanghai Research Institute of Criminal Science and Technology, Zhongshan North No 1 Road, Shanghai, 200083, China.
| | - Ping Shi
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China.
- Qinghai Provincial Key Laboratory of Qinghai-Tibet Plateau Biological Resources, Northwest Institute of Plateau Biology, The Chinese Academy of Sciences, Xiguan Avenue 59, Xining, 11 Qinghai Province, 810001, China.
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10
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Soltanian S, Dehghani H. BORIS: a key regulator of cancer stemness. Cancer Cell Int 2018; 18:154. [PMID: 30323717 PMCID: PMC6173857 DOI: 10.1186/s12935-018-0650-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 09/27/2018] [Indexed: 02/07/2023] Open
Abstract
BORIS (CTCFL) is a DNA binding protein which is involved in tumorigenesis. Although, there are different opinions on the level of gene expression and function of BORIS in normal and cancer tissues, the results of many studies have classified BORIS as a protein belonging to cancer/testis (CT) genes, which are identified as a group of genes that are expressed normally in testis, and abnormally in various types of cancers. In testis, BORIS induces the expression of some male germ cell/testis specific genes, and plays crucial roles during spermatogenesis and production of sperm. In tumorigenesis, the role of BORIS in the expression induction of some CT genes and oncogenes, as well as increasing proliferation/viability of cancer cells has been demonstrated in many researches. In addition to cancer cells, some believe that BORIS is also expressed in normal conditions and plays a universal function in cell division and regulation of genes. The following is a comprehensive review on contradictory views on the expression pattern and biological function of BORIS in normal, as well as cancer cells/tissues, and presents some evidence that support the expression of BORIS in cancer stem cells (CSCs) and advanced stage/poorer differentiation grade of cancers. Boris is involved in the regulation of CSC cellular and molecular features such as self-renewal, chemo-resistance, tumorigenicity, sphere-forming ability, and migration capacity. Finally, the role of BORIS in regulating two important signaling pathways including Wnt/β-catenin and Notch in CSCs, and its ability in recruiting transcription factors or chromatin-remodeling proteins to induce tumorigenesis is discussed.
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Affiliation(s)
- Sara Soltanian
- Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Hesam Dehghani
- Department of Basic Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Azadi Square, Mashhad, 91775-1793 Iran
- Division of Biotechnology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
- Stem Cells and Regenerative Medicine Research Group, Research Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
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11
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Sobecka A, Blaszczak W, Barczak W, Golusinski P, Rubis B, Masternak MM, Suchorska WM, Golusinski W. hTERT promoter methylation status in peripheral blood leukocytes as a molecular marker of head and neck cancer progression. J Appl Genet 2018; 59:453-461. [PMID: 30088231 DOI: 10.1007/s13353-018-0458-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/13/2018] [Accepted: 07/18/2018] [Indexed: 01/02/2023]
Abstract
Cancer cells, including head and neck cancer cell carcinoma (HNSCC), are characterized by an increased telomerase activity. This enzymatic complex is active in approximately 80-90% of all malignancies, and is regulated by various factors, including methylation status of hTERT gene promoter. hTERT methylation pattern has been thoroughly studied so far. It was proved that hTERT is aberrantly methylated in tumor tissue versus healthy counterparts. However, such effect has not yet been investigated in PBLs (peripheral blood leukocytes) of cancer patients. The aim of this study was to analyze the hTERT gene promoter methylation status in blood leukocytes. DNA was extracted from PBL of 92 patients with histologically diagnosed HNSCC and 53 healthy controls. Methylation status of whole hTERT promoter fragment with independent analysis of each 19 CpG sites was performed using bisulfide conversion technique followed by sequencing of PCR products. Not significant (p = 0.0532) differences in the general frequency of hTERT CpG sites methylation were detected between patients and healthy controls. However, it was discovered that some of analyzed positions (CpG islands: 1 [p = 0.0235], 5 [p = 0.0462], 8 [p = 0.0343]) are significantly more often methylated in HNSCC patients than in controls. The opposite finding was observed in case of CpG position 2 (p = 0.0210). Furthermore, closer analysis of single CpG positions revealed differences in methylation status dependent on anatomical site and TNM classification. To conclude, hTERT promoter methylation status (general or single CpG sites) would be considered as a molecular markers of HNSCC diagnostics.
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Affiliation(s)
- Agnieszka Sobecka
- Department of Head and Neck Surgery, The Greater Poland Cancer Centre, Poznan University of Medical Sciences, Garbary 15 Str, 61-866, Poznan, Poland
- Radiobiology Laboratory, The Greater Poland Cancer Centre, Garbary 15 Str, 61-866, Poznan, Poland
| | - Wiktoria Blaszczak
- Radiobiology Laboratory, The Greater Poland Cancer Centre, Garbary 15 Str, 61-866, Poznan, Poland
| | - Wojciech Barczak
- Department of Head and Neck Surgery, The Greater Poland Cancer Centre, Poznan University of Medical Sciences, Garbary 15 Str, 61-866, Poznan, Poland.
- Radiobiology Laboratory, The Greater Poland Cancer Centre, Garbary 15 Str, 61-866, Poznan, Poland.
| | - Pawel Golusinski
- Department of Head and Neck Surgery, The Greater Poland Cancer Centre, Poznan University of Medical Sciences, Garbary 15 Str, 61-866, Poznan, Poland
- Head and Neck Cancer Biology Laboratory, Department of Biology and Environmental Studies, Poznan University of Medical Sciences, Poznan, Poland
| | - Blazej Rubis
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, Przybyszewskiego 49 Str, 60-355, Poznan, Poland
| | - Michal M Masternak
- Department of Head and Neck Surgery, The Greater Poland Cancer Centre, Poznan University of Medical Sciences, Garbary 15 Str, 61-866, Poznan, Poland
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA
| | - Wiktoria M Suchorska
- Radiobiology Laboratory, The Greater Poland Cancer Centre, Garbary 15 Str, 61-866, Poznan, Poland
- Department of Electroradiology, Poznan University of Medical Sciences, Garbary 15 Str, 61-866, Poznan, Poland
| | - Wojciech Golusinski
- Department of Head and Neck Surgery, The Greater Poland Cancer Centre, Poznan University of Medical Sciences, Garbary 15 Str, 61-866, Poznan, Poland
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12
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Gaspar TB, Sá A, Lopes JM, Sobrinho-Simões M, Soares P, Vinagre J. Telomere Maintenance Mechanisms in Cancer. Genes (Basel) 2018; 9:E241. [PMID: 29751586 PMCID: PMC5977181 DOI: 10.3390/genes9050241] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 04/20/2018] [Accepted: 04/23/2018] [Indexed: 12/12/2022] Open
Abstract
Tumour cells can adopt telomere maintenance mechanisms (TMMs) to avoid telomere shortening, an inevitable process due to successive cell divisions. In most tumour cells, telomere length (TL) is maintained by reactivation of telomerase, while a small part acquires immortality through the telomerase-independent alternative lengthening of telomeres (ALT) mechanism. In the last years, a great amount of data was generated, and different TMMs were reported and explained in detail, benefiting from genome-scale studies of major importance. In this review, we address seven different TMMs in tumour cells: mutations of the TERT promoter (TERTp), amplification of the genes TERT and TERC, polymorphic variants of the TERT gene and of its promoter, rearrangements of the TERT gene, epigenetic changes, ALT, and non-defined TMM (NDTMM). We gathered information from over fifty thousand patients reported in 288 papers in the last years. This wide data collection enabled us to portray, by organ/system and histotypes, the prevalence of TERTp mutations, TERT and TERC amplifications, and ALT in human tumours. Based on this information, we discuss the putative future clinical impact of the aforementioned mechanisms on the malignant transformation process in different setups, and provide insights for screening, prognosis, and patient management stratification.
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Affiliation(s)
- Tiago Bordeira Gaspar
- Cancer Signaling and Metabolism Group, Institute for Research and Innovation in Health Sciences (i3S), University of Porto, 4200-135 Porto, Portugal.
- Cancer Signaling and Metabolism Group, Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal.
- Medical Faculty of University of Porto (FMUP), 4200-139 Porto, Portugal.
- Abel Salazar Biomedical Sciences Institute (ICBAS), University of Porto, 4050-313 Porto, Portugal.
| | - Ana Sá
- Cancer Signaling and Metabolism Group, Institute for Research and Innovation in Health Sciences (i3S), University of Porto, 4200-135 Porto, Portugal.
- Cancer Signaling and Metabolism Group, Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal.
- Abel Salazar Biomedical Sciences Institute (ICBAS), University of Porto, 4050-313 Porto, Portugal.
| | - José Manuel Lopes
- Cancer Signaling and Metabolism Group, Institute for Research and Innovation in Health Sciences (i3S), University of Porto, 4200-135 Porto, Portugal.
- Cancer Signaling and Metabolism Group, Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal.
- Medical Faculty of University of Porto (FMUP), 4200-139 Porto, Portugal.
- Department of Pathology and Oncology, Centro Hospitalar São João, 4200-139 Porto, Portugal.
| | - Manuel Sobrinho-Simões
- Cancer Signaling and Metabolism Group, Institute for Research and Innovation in Health Sciences (i3S), University of Porto, 4200-135 Porto, Portugal.
- Cancer Signaling and Metabolism Group, Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal.
- Medical Faculty of University of Porto (FMUP), 4200-139 Porto, Portugal.
- Department of Pathology and Oncology, Centro Hospitalar São João, 4200-139 Porto, Portugal.
| | - Paula Soares
- Cancer Signaling and Metabolism Group, Institute for Research and Innovation in Health Sciences (i3S), University of Porto, 4200-135 Porto, Portugal.
- Cancer Signaling and Metabolism Group, Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal.
- Abel Salazar Biomedical Sciences Institute (ICBAS), University of Porto, 4050-313 Porto, Portugal.
| | - João Vinagre
- Cancer Signaling and Metabolism Group, Institute for Research and Innovation in Health Sciences (i3S), University of Porto, 4200-135 Porto, Portugal.
- Cancer Signaling and Metabolism Group, Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal.
- Medical Faculty of University of Porto (FMUP), 4200-139 Porto, Portugal.
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Hassani S, Khaleghian A, Ahmadian S, Alizadeh S, Alimoghaddam K, Ghavamzadeh A, Ghaffari SH. Redistribution of cell cycle by arsenic trioxide is associated with demethylation and expression changes of cell cycle related genes in acute promyelocytic leukemia cell line (NB4). Ann Hematol 2017; 97:83-93. [DOI: 10.1007/s00277-017-3163-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 10/24/2017] [Indexed: 01/11/2023]
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14
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Farahzadi R, Fathi E, Mesbah-Namin SA, Zarghami N. Zinc sulfate contributes to promote telomere length extension via increasing telomerase gene expression, telomerase activity and change in the TERT gene promoter CpG island methylation status of human adipose-derived mesenchymal stem cells. PLoS One 2017; 12:e0188052. [PMID: 29145503 PMCID: PMC5690675 DOI: 10.1371/journal.pone.0188052] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 10/31/2017] [Indexed: 12/16/2022] Open
Abstract
The use of mesenchymal stem cells (MSCs) for cell therapy and regenerative medicine has received widespread attention over the past few years, but their application can be complicated by factors such as reduction in proliferation potential, the senescent tendency of the MSCs upon expansion and their age-dependent decline in number and function. It was shown that all the mentioned features were accompanied by a reduction in telomerase activity and telomere shortening. Furthermore, the role of epigenetic changes in aging, especially changes in promoter methylation, was reported. In this study, MSCs were isolated from the adipose tissue with enzymatic digestion. In addition, immunocytochemistry staining and flow cytometric analysis were performed to investigate the cell-surface markers. In addition, alizarin red-S, sudan III, toluidine blue, and cresyl violet staining were performed to evaluate the multi-lineage differentiation of hADSCs. In order to improve the effective application of MSCs, these cells were treated with 1.5 × 10-8 and 2.99 × 10-10 M of ZnSO4 for 48 hours. The length of the absolute telomere, human telomerase reverse transcriptase (hTERT) gene expression, telomerase activity, the investigation of methylation status of the hTERT gene promoter and the percentage of senescent cells were analyzed with quantitative real-time PCR, PCR-ELISA TRAP assay, methylation specific PCR (MSP), and beta-galactosidase (SA-β-gal) staining, respectively. The results showed that the telomere length, the hTERT gene expression, and the telomerase activity had significantly increased. In addition, the percentage of senescent cells had significantly decreased and changes in the methylation status of the CpG islands in the hTERT promoter region under treatment with ZnSO4 were seen. In conclusion, it seems that ZnSO4 as a proper antioxidant could improve the aging-related features due to lengthening of the telomeres, increasing the telomerase gene expression, telomerase activity, decreasing aging, and changing the methylation status of hTERT promoter; it could potentially beneficial for enhancing the application of aged-MSCs.
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Affiliation(s)
- Raheleh Farahzadi
- Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Clinical Biochemistry, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ezzatollah Fathi
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran
| | - Seyed Alireza Mesbah-Namin
- Department of Clinical Biochemistry, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Nosratollah Zarghami
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
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15
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Liu L, Liu C, Fotouhi O, Fan Y, Wang K, Xia C, Shi B, Zhang G, Wang K, Kong F, Larsson C, Hu S, Xu D. TERT Promoter Hypermethylation in Gastrointestinal Cancer: A Potential Stool Biomarker. Oncologist 2017; 22:1178-1188. [PMID: 28754720 PMCID: PMC5634768 DOI: 10.1634/theoncologist.2017-0064] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 04/18/2017] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND There is a high demand for noninvasive screening tools for gastrointestinal cancer (GIC) detection, and GIC-specific markers are required for such purposes. It is established that induction of the telomerase reverse transcriptase gene (TERT) coupled with telomerase activation is essential for cancer development/progression and aberrant TERT promoter methylation of specific 5'-C-phosphate-G-3' (CpGs) has been linked to TERT induction in oncogenesis. Here we analyzed TERT promoter methylation in fecal samples from GIC patients and healthy adults and determined its value as a stool biomarker for GIC detection. MATERIALS AND METHODS Sixty-nine GIC patients (34 colorectal carcinoma and 35 gastric cancer) and 62 healthy adults were recruited and fecal samples were collected. Paired tumors and adjacent non-cancerous tissues from 34 patients and normal mucosa tissues from 12 healthy individuals were collected. TERT promoter methylation density was determined using pyrosequencing. RESULTS We identified two GIC-specific methylation sites at -218 (CpG site 1) and -210 (CpG site 2) in the TERT promoter in tumor tissues. Methylated TERT promoter CpG sites 1 and 2 were also detectable in patient stool, while only background levels were observed in healthy individuals. The overall sensitivity reached 52.2% (95% confidence interval [CI]: 48.3-56.0) for fecal methylated TERT promoter assays at 90% specificity, which was comparable to other known stool methylation markers for GIC detection. The combined assays of fecal TERT promoter methylation and occult blood (OB) significantly improved sensitivity and specificity in colorectal cancer (area under curves for methylation alone: 0.798, 95% CI: 0.707-0.889 vs. methylation + OB: 0.920, 95% CI: 0.859-0.981; p = .028), but not in gastric cancer. CONCLUSION This proof-of-concept study suggests the feasibility of stool TERT promoter methylation analyses as an additional tool in noninvasive GIC screening. IMPLICATIONS FOR PRACTICE Induction of telomerase reverse transcriptase (TERT) expression coupled with telomerase activation is essential for cancer development/progression, while aberrant TERT promoter methylation has been linked to TERT induction in oncogenesis. We identified two cancer-specific methylation sites (CpG1 and 2) in the TERT promoter in tumors from GIC patients. Methylated TERT promoter CpG sites 1 and 2 were detectable in patient stool, while only background levels were observed in healthy individuals. The sensitivity and specificity was comparable to other known stool methylation markers for GIC detection. This proof-of-concept study suggests the feasibility of stool TERT promoter methylation analyses for noninvasive screening of GIC.
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Affiliation(s)
- Li Liu
- Departments of General Surgery, Jinan, People's Republic of China
- Shandong University, School of Nursing, Jinan, People's Republic of China
| | - Cheng Liu
- Urology, Shandong University Qilu Hospital, Jinan, People's Republic of China
- Shandong University-Karolinska Institutet Collaborative Laboratory for Cancer Research, Jinan, People's Republic of China
| | - Omid Fotouhi
- Department of Oncology-Pathology, Karolinska Institutet, and Cancer Center Karolinska, Karolinska University Hospital, Stockholm, Sweden
| | - Yidong Fan
- Urology, Shandong University Qilu Hospital, Jinan, People's Republic of China
- Shandong University-Karolinska Institutet Collaborative Laboratory for Cancer Research, Jinan, People's Republic of China
| | - Kun Wang
- Department of Urology, Tianjin Medical University Cancer Institute & Hospital, Tianjin, People's Republic of China
| | - Chuanyou Xia
- Urology, Shandong University Qilu Hospital, Jinan, People's Republic of China
- Department of Medicine, Division of Hematology and Centre for Molecular Medicine, Karolinska University Hospital Solna and Karolinska Institutet, Stockholm, Sweden
| | - Benkang Shi
- Urology, Shandong University Qilu Hospital, Jinan, People's Republic of China
| | - Guangyong Zhang
- Departments of General Surgery, Jinan, People's Republic of China
| | - Kexin Wang
- Departments of General Surgery, Jinan, People's Republic of China
| | - Feng Kong
- Central Research Laboratory, Shandong University Second Hospital, Jinan, People's Republic of China
| | - Catharina Larsson
- Department of Oncology-Pathology, Karolinska Institutet, and Cancer Center Karolinska, Karolinska University Hospital, Stockholm, Sweden
| | - Sanyuan Hu
- Departments of General Surgery, Jinan, People's Republic of China
| | - Dawei Xu
- Shandong University-Karolinska Institutet Collaborative Laboratory for Cancer Research, Jinan, People's Republic of China
- Department of Medicine, Division of Hematology and Centre for Molecular Medicine, Karolinska University Hospital Solna and Karolinska Institutet, Stockholm, Sweden
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16
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Van Tongelen A, Loriot A, De Smet C. Oncogenic roles of DNA hypomethylation through the activation of cancer-germline genes. Cancer Lett 2017; 396:130-137. [DOI: 10.1016/j.canlet.2017.03.029] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 03/16/2017] [Accepted: 03/16/2017] [Indexed: 12/19/2022]
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17
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Avin BA, Umbricht CB, Zeiger MA. Human telomerase reverse transcriptase regulation by DNA methylation, transcription factor binding and alternative splicing (Review). Int J Oncol 2016; 49:2199-2205. [PMID: 27779655 DOI: 10.3892/ijo.2016.3743] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 10/17/2016] [Indexed: 12/31/2022] Open
Abstract
The catalytic subunit of telomerase, human telomerase reverse transcriptase (hTERT), plays an essential role in telomere maintenance to oppose cellular senescence and, is highly regulated in normal and cancerous cells. Regulation of hTERT occurs through multiple avenues, including a unique pattern of CpG promoter methylation and alternative splicing. Promoter methylation affects the binding of transcription factors, resulting in changes in expression of the gene. In addition to expression level changes, changes in promoter binding can affect alternative splicing in a cotranscriptional manner. The alternative splicing of hTERT results in either the full length transcript which can form the active telomerase complex with hTR, or numerous inactive isoforms. Both regulation strategies are exploited in cancer to activate telomerase, however, the exact mechanism is unknown. Therefore, unraveling the link between promoter methylation status and alternative splicing for hTERT could expose yet another level of hTERT regulation. In an attempt to provide insight into the cellular control of active telomerase in cancer, this review will discuss our current perspective on CpG methylation of the hTERT promoter region, summarize the different forms of alternatively spliced variants, and examine examples of transcription factor binding that affects splicing.
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Affiliation(s)
- Brittany A Avin
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Christopher B Umbricht
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Martha A Zeiger
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Transcription Regulation of the Human Telomerase Reverse Transcriptase (hTERT) Gene. Genes (Basel) 2016; 7:genes7080050. [PMID: 27548225 PMCID: PMC4999838 DOI: 10.3390/genes7080050] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/23/2016] [Accepted: 08/01/2016] [Indexed: 12/11/2022] Open
Abstract
Embryonic stem cells and induced pluripotent stem cells have the ability to maintain their telomere length via expression of an enzymatic complex called telomerase. Similarly, more than 85%–90% of cancer cells are found to upregulate the expression of telomerase, conferring them with the potential to proliferate indefinitely. Telomerase Reverse Transcriptase (TERT), the catalytic subunit of telomerase holoenzyme, is the rate-limiting factor in reconstituting telomerase activity in vivo. To date, the expression and function of the human Telomerase Reverse Transcriptase (hTERT) gene are known to be regulated at various molecular levels (including genetic, mRNA, protein and subcellular localization) by a number of diverse factors. Among these means of regulation, transcription modulation is the most important, as evident in its tight regulation in cancer cell survival as well as pluripotent stem cell maintenance and differentiation. Here, we discuss how hTERT gene transcription is regulated, mainly focusing on the contribution of trans-acting factors such as transcription factors and epigenetic modifiers, as well as genetic alterations in hTERT proximal promoter.
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19
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Telomerase: The Devil Inside. Genes (Basel) 2016; 7:genes7080043. [PMID: 27483324 PMCID: PMC4999831 DOI: 10.3390/genes7080043] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/23/2016] [Accepted: 07/25/2016] [Indexed: 01/04/2023] Open
Abstract
High telomerase activity is detected in nearly all human cancers but most human cells are devoid of telomerase activity. There is well-documented evidence that reactivation of telomerase occurs during cellular transformation. In humans, tumors can rely in reactivation of telomerase or originate in a telomerase positive stem/progenitor cell, or rely in alternative lengthening of telomeres, a telomerase-independent telomere-length maintenance mechanism. In this review, we will focus on the telomerase positive tumors. In this context, the recent findings that telomerase reverse transcriptase (TERT) promoter mutations represent the most common non-coding mutations in human cancer have flared up the long-standing discussion whether cancer originates from telomerase positive stem cells or telomerase reactivation is a final step in cellular transformation. Here, we will discuss the pros and cons of both concepts in the context of telomere length-dependent and telomere length-independent functions of telomerase. Together, these observations may provoke a re-evaluation of telomere and telomerase based therapies, both in telomerase inhibition for cancer therapy and telomerase activation for tissue regeneration and anti-ageing strategies.
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20
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Telomerase Expression by Aberrant Methylation of the TERT Promoter in Melanoma Arising in Giant Congenital Nevi. J Invest Dermatol 2016; 136:339-342. [PMID: 26763461 PMCID: PMC4731027 DOI: 10.1038/jid.2015.374] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2015] [Indexed: 11/30/2022]
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Lewis KA, Tollefsbol TO. Regulation of the Telomerase Reverse Transcriptase Subunit through Epigenetic Mechanisms. Front Genet 2016; 7:83. [PMID: 27242892 PMCID: PMC4860561 DOI: 10.3389/fgene.2016.00083] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 04/22/2016] [Indexed: 12/21/2022] Open
Abstract
Chromosome-shortening is characteristic of normal cells, and is known as the end replication problem. Telomerase is the enzyme responsible for extending the ends of the chromosomes in de novo synthesis, and occurs in germ cells as well as most malignant cancers. There are three subunits of telomerase: human telomerase RNA (hTERC), human telomerase associated protein (hTEP1), or dyskerin, and human telomerase reverse transcriptase (hTERT). hTERC and hTEP1 are constitutively expressed, so the enzymatic activity of telomerase is dependent on the transcription of hTERT. DNA methylation, histone methylation, and histone acetylation are basic epigenetic regulations involved in the expression of hTERT. Non-coding RNA can also serve as a form of epigenetic control of hTERT. This epigenetic-based regulation of hTERT is important in providing a mechanism for reversibility of hTERT control in various biological states. These include embryonic down-regulation of hTERT contributing to aging and the upregulation of hTERT playing a critical role in over 90% of cancers. Normal human somatic cells have a non-methylated/hypomethylated CpG island within the hTERT promoter region, while telomerase-positive cells paradoxically have at least a partially methylated promoter region that is opposite to the normal roles of DNA methylation. Histone acetylation of H3K9 within the promoter region is associated with an open chromatin state such that transcription machinery has the space to form. Histone methylation of hTERT has varied control of the gene, however. Mono- and dimethylation of H3K9 within the promoter region indicate silent euchromatin, while a trimethylated H3K9 enhances gene transcription. Non-coding RNAs can target epigenetic-modifying enzymes, as well as transcription factors involved in the control of hTERT. An epigenetics diet that can affect the epigenome of cancer cells is a recent fascination that has received much attention. By combining portions of this diet with epigenome-altering treatments, it is possible to selectively regulate the epigenetic control of hTERT and its expression.
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Affiliation(s)
- Kayla A Lewis
- Department of Biology, University of Alabama at Birmingham, Birmingham AL, USA
| | - Trygve O Tollefsbol
- Department of Biology, University of Alabama at Birmingham, BirminghamAL, USA; Comprehensive Center for Healthy Aging, University of Alabama at Birmingham, BirminghamAL, USA; Comprehensive Cancer Center, University of Alabama at Birmingham, BirminghamAL, USA; Nutrition Obesity Research Center, University of Alabama at Birmingham, BirminghamAL, USA; Comprehensive Diabetes Center, University of Alabama at Birmingham, BirminghamAL, USA
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22
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Zhang X, Li B, de Jonge N, Björkholm M, Xu D. The DNA methylation inhibitor induces telomere dysfunction and apoptosis of leukemia cells that is attenuated by telomerase over-expression. Oncotarget 2016; 6:4888-900. [PMID: 25682873 PMCID: PMC4467122 DOI: 10.18632/oncotarget.2917] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 12/14/2014] [Indexed: 01/27/2023] Open
Abstract
DNA methyltransferase inhibitors (DNMTIs) such as 5-azacytidine (5-AZA) have been used for treatment of acute myeloid leukemia (AML) and other malignancies. Although inhibiting global/gene-specific DNA methylation is widely accepted as a key mechanism behind DNMTI anti-tumor activity, other mechanisms are likely involved in DNMTI's action. Because telomerase reverse transcriptase (TERT) plays key roles in cancer through telomere elongation and telomere lengthening-independent activities, and TERT has been shown to confer chemo- or radio-resistance to cancer cells, we determine whether DNMTIs affect telomere function and whether TERT/telomerase interferes with their anti-cancer efficacy. We showed that 5-AZA induced DNA damage and telomere dysfunction in AML cell lines by demonstrating the presence of 53-BP1 foci and the co-localization of 53-BP1 foci with telomere signals, respectively. Telomere dysfunction was coupled with diminished TERT expression, shorter telomere and apoptosis in 5-AZA-treated cells. However, 5-AZA treatment did not lead to changes in the methylation status of subtelomere regions. Down-regulation of TERT expression similarly occurred in primary leukemic cells derived from AML patients exposed to 5-AZA. TERT over-expression significantly attenuated 5-AZA-mediated DNA damage, telomere dysfunction and apoptosis of AML cells. Collectively, 5-AZA mediates the down-regulation of TERT expression, and induces telomere dysfunction, which consequently exerts an anti-tumor activity.
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Affiliation(s)
- Xiaolu Zhang
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm, Sweden
| | - Bingnan Li
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm, Sweden
| | - Nick de Jonge
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm, Sweden
| | - Magnus Björkholm
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm, Sweden
| | - Dawei Xu
- Department of Medicine, Division of Hematology and Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital Solna, Stockholm, Sweden
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Bernadotte A, Mikhelson VM, Spivak IM. Markers of cellular senescence. Telomere shortening as a marker of cellular senescence. Aging (Albany NY) 2016; 8:3-11. [PMID: 26805432 PMCID: PMC4761709 DOI: 10.18632/aging.100871] [Citation(s) in RCA: 281] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
The cellular senescence definition comes to the fact of cells irreversible proliferation disability. Besides the cell cycle arrest, senescent cells go through some morphological, biochemical, and functional changes which are the signs of cellular senescence. The senescent cells (including replicative senescence and stress-induced premature senescence) of all the tissues look alike. They are metabolically active and possess the set of characteristics in vitro and in vivo, which are known as biomarkers of aging and cellular senescence. Among biomarkers of cellular senescence telomere shortening is a rather elegant frequently used biomarker. Validity of telomere shortening as a marker for cellular senescence is based on theoretical and experimental data.
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Affiliation(s)
- Alexandra Bernadotte
- Karolinska Institute, Department of Medical Biochemistry and Biophysics, Stockholm, 14157, Sweden
- St. Petersburg Institute of Bioregulation and Gerontology, Russian Academy of Sciences, Saint-Petersburg, 197110 Russia
| | - Victor M. Mikhelson
- Institute of Cytology, Russian Academy of Sciences, Saint-Petersburg, 194064, Russia
| | - Irina M. Spivak
- Institute of Cytology, Russian Academy of Sciences, Saint-Petersburg, 194064, Russia
- Saint-Petersburg's State University, Saint-Petersburg, 199034, Russia
- Saint-Petersburg's Polytechnic State University, Saint-Petersburg, 195251 Russia
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24
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Zhang H, Weng X, Ye J, He L, Zhou D, Liu Y. Promoter hypermethylation of TERT is associated with hepatocellular carcinoma in the Han Chinese population. Clin Res Hepatol Gastroenterol 2015; 39:600-9. [PMID: 25683523 DOI: 10.1016/j.clinre.2015.01.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 01/05/2015] [Accepted: 01/12/2015] [Indexed: 02/04/2023]
Abstract
BACKGROUND Upstream of the transcription start site (UTSS), hypermethylation of the telomerase reverse transcriptase (TERT) gene has been shown to be associated with tumour progression and a poor prognosis in paediatric brain tumours (Castelo-Branco 2013). It has been inferred that the UTSS region of TERT is a potentially accessible biomarker for various cancers. In this study, we aimed to explore the role of TERT in hepatocellular carcinoma (HCC) and to investigate whether the UTSS region of the TERT promoter shows the same methylation pattern in HCC. METHODS We analysed the results of a methylation assay for TERT, including the UTSS region, from 125 paired HCC samples using Mass Array EpiTyper (Sequenom, San Diego, CA, USA). To determine the relationship between TERT promoter methylation status and the TERT expression level, we analysed a validation group of 12 paired HCC samples and acquired the FPKM values for the TERT gene. RESULTS Our results showed aberrant methylation of the UTSS region of the TERT promoter in HCC (mean=15.1) compared with the adjacent normal tissues (mean=6.1, P<0.00001). Furthermore, a nearly 56-fold increase in TERT expression from the hypermethylated promoter was found in HCC (P<0.05), indicating a positive relationship between TERT methylation and expression. CONCLUSIONS As hypermethylation was positively correlated with high expression of TERT in HCC, TERT is likely to be involved in the aetiology of HCC. Our findings indicate that future studies on TERT might be fruitful.
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Affiliation(s)
- Hong Zhang
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PR China
| | - Xiaoling Weng
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PR China
| | - Junyi Ye
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PR China
| | - Lin He
- Bio-X Centre Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200030, PR China
| | - Daizhan Zhou
- Bio-X Centre Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai 200030, PR China.
| | - Yun Liu
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PR China.
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25
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Nickerson ML, Dancik GM, Im KM, Edwards MG, Turan S, Brown J, Ruiz-Rodriguez C, Owens C, Costello JC, Guo G, Tsang SX, Li Y, Zhou Q, Cai Z, Moore LE, Lucia MS, Dean M, Theodorescu D. Concurrent alterations in TERT, KDM6A, and the BRCA pathway in bladder cancer. Clin Cancer Res 2015; 20:4935-48. [PMID: 25225064 DOI: 10.1158/1078-0432.ccr-14-0330] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Genetic analysis of bladder cancer has revealed a number of frequently altered genes, including frequent alterations of the telomerase (TERT) gene promoter, although few altered genes have been functionally evaluated. Our objective is to characterize alterations observed by exome sequencing and sequencing of the TERT promoter, and to examine the functional relevance of histone lysine (K)-specific demethylase 6A (KDM6A/UTX), a frequently mutated histone demethylase, in bladder cancer. EXPERIMENTAL DESIGN We analyzed bladder cancer samples from 54 U.S. patients by exome and targeted sequencing and confirmed somatic variants using normal tissue from the same patient. We examined the biologic function of KDM6A using in vivo and in vitro assays. RESULTS We observed frequent somatic alterations in BRCA1 associated protein-1 (BAP1) in 15% of tumors, including deleterious alterations to the deubiquitinase active site and the nuclear localization signal. BAP1 mutations contribute to a high frequency of tumors with breast cancer (BRCA) DNA repair pathway alterations and were significantly associated with papillary histologic features in tumors. BAP1 and KDM6A mutations significantly co-occurred in tumors. Somatic variants altering the TERT promoter were found in 69% of tumors but were not correlated with alterations in other bladder cancer genes. We examined the function of KDM6A, altered in 24% of tumors, and show depletion in human bladder cancer cells, enhanced in vitro proliferation, in vivo tumor growth, and cell migration. CONCLUSIONS This study is the first to identify frequent BAP1 and BRCA pathway alterations in bladder cancer, show TERT promoter alterations are independent of other bladder cancer gene alterations, and show KDM6A loss is a driver of the bladder cancer phenotype.
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Affiliation(s)
- Michael L Nickerson
- Cancer and Inflammation Program, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | | | - Kate M Im
- Cancer and Inflammation Program, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Michael G Edwards
- Division of Pulmonary Sciences and Critical Care, Department of Medicine, University of Colorado, Denver, Aurora, Colorado
| | - Sevilay Turan
- Cancer and Inflammation Program, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | | | - Christina Ruiz-Rodriguez
- Cancer and Inflammation Program, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Charles Owens
- Department of Surgery, University of Colorado, Aurora, Colorado
| | - James C Costello
- Department of Pharmacology, University of Colorado, Aurora, Colorado
| | | | | | | | | | - Zhiming Cai
- Shenzhen Second People's Hospital, Shenzhen, China
| | - Lee E Moore
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, Maryland
| | - M Scott Lucia
- Department of Pathology, University of Colorado, Aurora, Colorado
| | - Michael Dean
- Cancer and Inflammation Program, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Dan Theodorescu
- Department of Surgery, University of Colorado, Aurora, Colorado. Department of Pharmacology, University of Colorado, Aurora, Colorado. University of Colorado Comprehensive Cancer Center, Aurora, Colorado.
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26
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Schütze DM, Kooter JM, Wilting SM, Meijer CJLM, Quint W, Snijders PJF, Steenbergen RDM. Longitudinal assessment of DNA methylation changes during HPVE6E7-induced immortalization of primary keratinocytes. Epigenetics 2015; 10:73-81. [PMID: 25580631 DOI: 10.4161/15592294.2014.990787] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
High-risk human papillomavirus (hrHPV)-induced immortalization and malignant transformation are accompanied by DNA methylation of host genes. To determine when methylation is established during cell immortalization and whether it is hrHPV-type dependent, DNA methylation was studied in a large panel of HPVE6E7-immortalized keratinocyte cell lines. These cell lines displayed different growth behaviors, i.e., continuous growth versus crisis period prior to immortalization, reflecting differential immortalization capacities of the 7 HPV-types (16/18/31/33/45/66/70) studied. In this study, cells were monitored for hypermethylation of 14 host genes (APC, CADM1, CYGB, FAM19A4, hTERT, mir124-1, mir124-2, mir124-3, MAL, PHACTR3, PRDM14, RASSF1A, ROBO3, and SFRP2) at 4 different stages during immortalization. A significant increase in overall methylation levels was seen with progression through each stage of immortalization. At stage 1 (pre-immortalization), a significant increase in methylation of hTERT, mir124-2, and PRDM14 was already apparent, which continued over time. Methylation of ROBO3 was significantly increased at stage 2 (early immortal), followed by CYGB (stage 3) and FAM19A4, MAL, PHACTR3, and SFRP2 (stage 4). Methylation patterns were mostly growth behavior independent. Yet, hTERT methylation levels were significantly increased in cells that just escaped from crisis. Bisulfite sequencing of hTERT confirmed increased methylation in immortal cells compared to controls, with the transcription core and known repressor sites remaining largely unmethylated. In conclusion, HPV-induced immortalization is associated with a sequential and progressive increase in promoter methylation of a subset of genes, which is mostly independent of the viral immortalization capacity.
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Affiliation(s)
- Denise M Schütze
- a Department of Pathology; Unit of Molecular Pathology ; VU University Medical Center ; Amsterdam , The Netherlands
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27
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Zhang D, Sun X, Liu J, Xie X, Cui W, Zhu Y. Homocysteine accelerates senescence of endothelial cells via DNA hypomethylation of human telomerase reverse transcriptase. Arterioscler Thromb Vasc Biol 2015; 35:71-8. [PMID: 25359865 DOI: 10.1161/atvbaha.114.303899] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Homocysteine can accelerate the senescence of endothelial progenitor cells or endothelial cells (ECs) via telomerase inactivation and length shortening. However, the underlying mechanism is unclear. Here, we investigated whether homocysteine promotes endothelial senescence by reducing the expression and activity of human telomerase reverse transcriptase (hTERT) by DNA methylation to reduce ECs telomerase activity. APPROACH AND RESULTS When compared with primary human umbilical vein endothelial cells grown under standard conditions, ECs with chronic homocysteine treatment showed accelerated upregulation of p16, p21, and p53, markers of cellular senescence, during 6 to 10 passages. Interestingly, homocysteine-stimulated but not angiotensin II-stimulated ECs senescence could be reversed by hypermethylation induced by folic acid or s-adenosylmethionine supplementation. Meanwhile, homocysteine promoted the shortening of telomere length specifically related to restoration of hTERT transcriptional expression and CCCTC-binding factor binding sites with hTERT promoter hypomethylation, as detected by quantitative real-time polymerase chain reaction, Western blot, methylation-specific polymerase chain reaction, and bisulfite sequencing assay. Electrophoretic mobility shift assay and chromatin immunoprecipitation results showed that homocysteine-reduced telomere activity and homocysteine-induced EC senescence might contribute to hTERT promoter demethylation by increasing CCCTC-binding factor repression and interfering in the SP1 binding to the demethylated hTERT promoter, which might relate with reduced of DNA methyltransferase 1. Furthermore, the CCCTC-binding factor-dependent mechanism of homocysteine-reduced hTERT expression via DNA demethylation was confirmed in aortic endothelia of mice with hyperhomocysteine levels. CONCLUSIONS CCCTC-binding factor and SP1 cross talk may contribute to homocysteine-reduced hTERT DNA methylation and expression in endothelial senescence.
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Affiliation(s)
- Donghong Zhang
- From the Department of Clinical Laboratory, Peking Union Medical College and Peking Union Medical College Hospital, Beijing, China (D.Z., W.C.); Department of Physiology and Pathophysiology, Key Laboratory of Cardiovascular Science of Ministry of Education, Peking University Health Science Center, Beijing, China (W.C.); Cardiovascular Research Center, Shantou University Medical College, Shantou, Guangdong, China (D.Z., J.L., X.X.); and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China (Y.Z.)
| | - Xiaoli Sun
- From the Department of Clinical Laboratory, Peking Union Medical College and Peking Union Medical College Hospital, Beijing, China (D.Z., W.C.); Department of Physiology and Pathophysiology, Key Laboratory of Cardiovascular Science of Ministry of Education, Peking University Health Science Center, Beijing, China (W.C.); Cardiovascular Research Center, Shantou University Medical College, Shantou, Guangdong, China (D.Z., J.L., X.X.); and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China (Y.Z.)
| | - Jianlan Liu
- From the Department of Clinical Laboratory, Peking Union Medical College and Peking Union Medical College Hospital, Beijing, China (D.Z., W.C.); Department of Physiology and Pathophysiology, Key Laboratory of Cardiovascular Science of Ministry of Education, Peking University Health Science Center, Beijing, China (W.C.); Cardiovascular Research Center, Shantou University Medical College, Shantou, Guangdong, China (D.Z., J.L., X.X.); and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China (Y.Z.)
| | - Xina Xie
- From the Department of Clinical Laboratory, Peking Union Medical College and Peking Union Medical College Hospital, Beijing, China (D.Z., W.C.); Department of Physiology and Pathophysiology, Key Laboratory of Cardiovascular Science of Ministry of Education, Peking University Health Science Center, Beijing, China (W.C.); Cardiovascular Research Center, Shantou University Medical College, Shantou, Guangdong, China (D.Z., J.L., X.X.); and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China (Y.Z.)
| | - Wei Cui
- From the Department of Clinical Laboratory, Peking Union Medical College and Peking Union Medical College Hospital, Beijing, China (D.Z., W.C.); Department of Physiology and Pathophysiology, Key Laboratory of Cardiovascular Science of Ministry of Education, Peking University Health Science Center, Beijing, China (W.C.); Cardiovascular Research Center, Shantou University Medical College, Shantou, Guangdong, China (D.Z., J.L., X.X.); and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China (Y.Z.).
| | - Yi Zhu
- From the Department of Clinical Laboratory, Peking Union Medical College and Peking Union Medical College Hospital, Beijing, China (D.Z., W.C.); Department of Physiology and Pathophysiology, Key Laboratory of Cardiovascular Science of Ministry of Education, Peking University Health Science Center, Beijing, China (W.C.); Cardiovascular Research Center, Shantou University Medical College, Shantou, Guangdong, China (D.Z., J.L., X.X.); and Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China (Y.Z.).
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Abstract
Cancer is a genetic and epigenetic disease. Multiple genetic and epigenetic changes have been studied in cervical cancer; however, such changes are selected for during tumorigenesis and tumor aggression is not yet clear. Cervical cancer is a multistep process with accumulation of genetic and epigenetic alterations in regulatory genes, leading to activation of oncogenes and inactivation or loss of tumor suppressor genes. In cervical cancer, epigenetic alterations can affect the expression of papillomaviral as well as host genes in relation to stages representing the multistep process of carcinogenesis.
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29
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Zhang ZX, Wang Y, Tao ZZ, Chen SM, Xiao BK, Zhou T. Subtelomeric Demethylation Deregulated hTERT Expression, Telomerase Activity, and Telomere Length in Four Nasopharyngeal Carcinoma Cell Lines. Cancer Biother Radiopharm 2014; 29:289-94. [PMID: 25153197 DOI: 10.1089/cbr.2013.1581] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Zi-Xiong Zhang
- Department of Otolaryngology, Head and Neck Surgery, Renmin Hospital of Wuhan University , Wuhan, People's Republic of China
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30
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Grandjenette C, Schnekenburger M, Karius T, Ghelfi J, Gaigneaux A, Henry E, Dicato M, Diederich M. 5-aza-2'-deoxycytidine-mediated c-myc Down-regulation triggers telomere-dependent senescence by regulating human telomerase reverse transcriptase in chronic myeloid leukemia. Neoplasia 2014; 16:511-28. [PMID: 24970385 PMCID: PMC4198755 DOI: 10.1016/j.neo.2014.05.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/17/2014] [Accepted: 05/21/2014] [Indexed: 12/11/2022] Open
Abstract
Increased proliferation rates as well as resistance to apoptosis are considered major obstacles for the treatment of patients with chronic myelogenous leukemia (CML), thus highlighting the need for novel therapeutic approaches. Since senescence has been recognized as a physiological barrier against tumorigenesis, senescence-based therapy could represent a new strategy against CML. DNA demethylating agent 5-aza-2′-deoxycytidine (DAC) was reported to induce cellular senescence but underlying mechanisms remain to be elucidated. Here, we report that exposure to DAC triggers senescence in chronic leukemia cell lines as evidenced by increased senescence-associated β-galactosidase activity and lysosomal mass, accompanied by an up-regulation of cell cycle-related genes. We provide evidence that DAC is able to decrease telomere length, to reduce telomerase activity and to decrease human telomerase reverse transcriptase (hTERT) expression through decreased binding of c-myc to the hTERT promoter. Altogether, our results reveal the role of c-myc in telomere-dependent DAC-induced senescence and therefore provide new clues for improving chronic human leukemia treatments.
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Affiliation(s)
- Cindy Grandjenette
- Laboratoire de Biologie Moléculaire et Cellulaire du Cancer, Hôpital Kirchberg, 9, rue Edward Steichen, L-2540 Luxembourg, Luxembourg
| | - Michael Schnekenburger
- Laboratoire de Biologie Moléculaire et Cellulaire du Cancer, Hôpital Kirchberg, 9, rue Edward Steichen, L-2540 Luxembourg, Luxembourg
| | - Tommy Karius
- Laboratoire de Biologie Moléculaire et Cellulaire du Cancer, Hôpital Kirchberg, 9, rue Edward Steichen, L-2540 Luxembourg, Luxembourg
| | - Jenny Ghelfi
- Laboratoire de Biologie Moléculaire et Cellulaire du Cancer, Hôpital Kirchberg, 9, rue Edward Steichen, L-2540 Luxembourg, Luxembourg
| | - Anthoula Gaigneaux
- Laboratoire de Biologie Moléculaire et Cellulaire du Cancer, Hôpital Kirchberg, 9, rue Edward Steichen, L-2540 Luxembourg, Luxembourg
| | - Estelle Henry
- Laboratoire de Biologie Moléculaire et Cellulaire du Cancer, Hôpital Kirchberg, 9, rue Edward Steichen, L-2540 Luxembourg, Luxembourg
| | - Mario Dicato
- Laboratoire de Biologie Moléculaire et Cellulaire du Cancer, Hôpital Kirchberg, 9, rue Edward Steichen, L-2540 Luxembourg, Luxembourg
| | - Marc Diederich
- College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
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31
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Zhang DH, Wen XM, Zhang L, Cui W. DNA Methylation of Human Telomerase Reverse Transcriptase Associated With Leukocyte Telomere Length Shortening in Hyperhomocysteinemia-Type Hypertension in Humans and in a Rat Model. Circ J 2014; 78:1915-23. [DOI: 10.1253/circj.cj-14-0233] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Dong-hong Zhang
- Department of Clinical Laboratory, Peking Union Medical College Hospital and Peking Union Medical College
| | - Xue-mei Wen
- Department of Clinical Laboratory, Peking Union Medical College Hospital and Peking Union Medical College
| | - Lin Zhang
- Department of Clinical Laboratory, Peking Union Medical College Hospital and Peking Union Medical College
| | - Wei Cui
- Department of Clinical Laboratory, Peking Union Medical College Hospital and Peking Union Medical College
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32
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Eldholm V, Haugen A, Zienolddiny S. CTCF mediates the TERT enhancer-promoter interactions in lung cancer cells: identification of a novel enhancer region involved in the regulation of TERT gene. Int J Cancer 2013; 134:2305-13. [PMID: 24174344 DOI: 10.1002/ijc.28570] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/19/2013] [Accepted: 10/18/2013] [Indexed: 01/18/2023]
Abstract
Telomerase activation is a hallmark of cancer. Although the regulation of the telomerase reverse transcriptase catalytic subunit (TERT), the rate-limiting factor for telomerase activity, has been studied intensively it remains incompletely understood. In cells devoid of telomerase activity, TERT is embedded in a region of condensed chromatin and the chromatin remodeling protein CCCTC-binding factor (CTCF) has been implicated in the inhibition of TERT expression. The importance of TERT activation for cellular immortalization and carcinogenesis is attested by the fact that the gene is expressed in more than 90% of immortal cell lines and tumors and that gain of TERT is the most frequent amplification event in early stage lung cancer. This study was designed to study the mechanisms of regulation of the TERT gene expression by the CTCF transcription factor in three human lung cancer cell lines, A427, A549 and H838. Depletion of CTCF by siRNA resulted in reduced TERT mRNA levels in two (A427 and A549) of the three cell lines. A novel enhancer element was identified approximately 4.5 kb upstream of the TERT transcription start site. Chromatin immunoprecipitation experiments revealed recruitment of CTCF to this enhancer element. Chromosome conformation capture experiments demonstrated the presence of CTCF-dependent chromatin loops between this enhancer element and the TERT proximal promoter in A427 and A549 cell lines. In summary, the results show that CTCF plays an important role in maintaining TERT expression in a subset of human lung cancer cell lines. This role may be due to CTCF-dependent enhancer-promoter interactions.
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Affiliation(s)
- Vegard Eldholm
- Department of Chemical and Biological Work Environment, National Institute of Occupational Health, Oslo, Norway
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33
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Zhang D, Wen X, Wu W, Xu E, Zhang Y, Cui W. Homocysteine-related hTERT DNA demethylation contributes to shortened leukocyte telomere length in atherosclerosis. Atherosclerosis 2013; 231:173-9. [PMID: 24125430 DOI: 10.1016/j.atherosclerosis.2013.08.029] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 08/16/2013] [Accepted: 08/26/2013] [Indexed: 12/25/2022]
Abstract
AIMS Leukocyte telomere length (LTL) is shortened in patients with clinical atherosclerosis (AS). Here we aimed to explore the contribution of elevated homocysteine (Hcy) level to LTL shortening in AS patients and the underlying mechanism. METHODS Circulating leukocytes were collected from 197 patients with AS and 165 sex- and age-matched healthy subjects for LTL determination. mRNA expression or DNA methylation of human telomerase reverse transcriptase (hTERT) was determined by real-time PCR and methylation-specific PCR assay, respectively. We established a hyperhomocysteinemia (HHcy) mice model to confirm human results. RESULTS Hcy was negatively correlated with LTL shortening in AS patients (r = -0.179, p = 0.015) and controls (r = -0.146, p = 0.031). Serum folate and high-sensitivity C-reactive protein levels significantly interacted with Hcy in LTL shortening. Hcy was related to hTERT mRNA downregulation and promoter demethylation, which combined was associated with LTL shortening in AS patients. Hcy-induced LTL shortening did not differ by sites of AS lesions or infarction. Similar to clinical observations, our HHcy mice model suggested that Hcy induced DNA demethylation and downregulation of mouse TERT and further contributed to LTL shortening. CONCLUSIONS Elevated Hcy level induced DNA demethylation of hTERT and was closely related with hTERT downregulation, which led to LTL shortening in AS. These findings provide novel insights into an epigenetic mechanism for Hcy-related AS.
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Affiliation(s)
- Donghong Zhang
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, 1 Shuaifuyuan, Beijing 100730, China
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ZHANG WENXUAN, XING LINA. RNAi gene therapy of SiHa cells via targeting human TERT induces growth inhibition and enhances radiosensitivity. Int J Oncol 2013; 43:1228-34. [DOI: 10.3892/ijo.2013.2051] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 07/16/2013] [Indexed: 11/06/2022] Open
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35
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Li J, Cao X, Fang Y, Liao ZE, Liu YY, Huang BD, Han YJ. Overexpression of hTERT in potentially malignant colorectal laterally spreading tumors. Mol Med Rep 2013; 7:1409-12. [PMID: 23525166 DOI: 10.3892/mmr.2013.1376] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 02/27/2013] [Indexed: 11/06/2022] Open
Abstract
Human telomerase reverse transcriptase (hTERT) is the main subunit of the core enzyme telomerase, which consists of three subunits. Telomeres are essential for chromosomal stability and integrity, protecting the ends of chromosomes from degradation and preventing chromosomal end fusions and recombination. A loss of telomere function is a major mechanism for the generation of chromosomal abnormalities. Telomere shortening leads to mutations, chromosome rearrangements and translocations. Colorectal laterally spreading tumors (LSTs) are a special type of superficial colorectal tumor. They are considered to have a high malignancy potential. The aim of the present study was to characterize the expression of hTERT in an LST cell line and paraffin sections. Immunohistochemistry was utilized to examine the protein expression of hTERT in the LST cell line, 48 resected LSTs, 48 protruded-type colorectal adenomas (PAs) and 48 normal mucosa samples. Statistical analyses were applied to test the associations between hTERT expression and clinicopathological parameters. The present study demonstrated that the positive expression levels of hTERT in LSTs, PAs and normal mucosa were 60.4, 22.9 and 10%, respectively. Compared with polypi and normal mucosa, the expression levels of hTERT were significantly increased in LSTs. The expression of hTERT was also observed in the LST cell line. The expression of hTERT was significantly higher in LSTs, which may indicate a potential for malignancy.
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Affiliation(s)
- Jun Li
- Department of Traditional Chinese Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, PR China
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Ogrocká A, Sýkorová E, Fajkus J, Fojtová M. Developmental silencing of the AtTERT gene is associated with increased H3K27me3 loading and maintenance of its euchromatic environment. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:4233-41. [PMID: 22511802 PMCID: PMC3398451 DOI: 10.1093/jxb/ers107] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Telomerase, an enzyme responsible for the maintenance of linear chromosome ends, is precisely regulated during plant development. In animals, involvement of the epigenetic state of the telomerase reverse transcriptase (TERT) gene in the complex regulation of telomerase activity has been reported. To reveal whether epigenetic mechanisms participate in the regulation of plant telomerase, the relationship between telomerase activity in tissues of Arabidopsis thaliana and DNA methylation and histone modifications in the A. thaliana TERT (AtTERT) upstream region was studied. As expected, a gradual decrease of telomerase activity during leaf maturation was observed. A different pattern with a more progressive loss of telomerase activity and AtTERT transcription during leaf development was revealed in MET1 gene-knockout mutants. Analysis of DNA methylation in the AtTERT upstream region showed low levels of methylated cytosines without notable differences between telomerase-positive and telomerase-negative wild-type tissues. Surprisingly, a high level of CG methylation was found in the AtTERT coding region, although this type of methylation is a characteristic attribute of constitutively expressed genes. Analysis of chromatin modifications in the AtTERT upstream region and in exon 5 showed increased loading of the H3K27me3 mark in the telomerase-negative mature leaf compared to telomerase-positive seedlings, whereas H3K4me3, H3K9Ac, and H3K9me2 were approximately at the same level. Consistently, the chromatin structure of the AtTERT gene was maintained. These results are discussed in the context of the general involvement of epigenetic mechanisms in the regulation of gene expression and with respect to similar studies performed in animal models.
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Affiliation(s)
- Anna Ogrocká
- CEITEC – Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Eva Sýkorová
- CEITEC – Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., Královopolská 65, 612 65 Brno, Czech Republic
| | - Jiří Fajkus
- CEITEC – Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., Královopolská 65, 612 65 Brno, Czech Republic
| | - Miloslava Fojtová
- CEITEC – Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
- To whom correspondence should be addressed. E-mail:
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Tao SF, Zhang CS, Guo XL, Xu Y, Zhang SS, Song JR, Li R, Wu MC, Wei LX. Anti-tumor effect of 5-aza-2'-deoxycytidine by inhibiting telomerase activity in hepatocellular carcinoma cells. World J Gastroenterol 2012; 18:2334-43. [PMID: 22654424 PMCID: PMC3353367 DOI: 10.3748/wjg.v18.i19.2334] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 12/07/2011] [Accepted: 12/14/2011] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effect of the demethylating reagent 5-aza-2’-deoxycitidine (DAC) on telomerase activity in hepatocellular carcinoma (HCC) cell lines, SMMC-7721 and HepG2.
METHODS: The related gene expression in cell lines was examined by real-time reverse transcription-polymerase chain reaction and Western blotting analysis. The telomerase activity was examined by telomeric repeat amplification protocol-enzyme-linked immunosorbent assay and DNA methylation was determined by methylation-specific polymerase chain reaction.
RESULTS: The telomerase activity was significantly reduced in both cell lines treated with DAC, accompanied by downregulation of telomerase reverse transcriptase (hTERT). We also observed the effect of DAC on the methylation status of hTERT promoter and the expression of regulatory genes, such as c-myc, p15, p16, p21, E2F1, and WT1. The methylation status of hTERT promoter could be reversed in SMMC-7721 by DAC, but not in HepG2 cells. However, p16 expression could be reactivated by demethylation of its promoter, and c-Myc expression was repressed in both cell lines. Moreover, DAC could enhance the sensitivity to the chemotherapeutic agents, such as cisplatin, by induction of apoptosis of HCC cells.
CONCLUSION: The DAC exerts its anti-tumor effects in HCC cells by inhibiting the telomerase activity.
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Cifuentes-Rojas C, Shippen DE. Telomerase regulation. Mutat Res 2012; 730:20-7. [PMID: 22032831 PMCID: PMC3256259 DOI: 10.1016/j.mrfmmm.2011.10.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 09/15/2011] [Accepted: 10/12/2011] [Indexed: 02/05/2023]
Abstract
The intimate connection between telomerase regulation and human disease is now well established. The molecular basis for telomerase regulation is highly complex and entails multiple layers of control. While the major target of enzyme regulation is the catalytic subunit TERT, the RNA subunit of telomerase is also implicated in telomerase control. In addition, alterations in gene dosage and alternative isoforms of core telomerase components have been described. Finally, telomerase localization, recruitment to the telomere and enzymology at the chromosome terminus are all subject to modulation. In this review we summarize recent advances in understanding fundamental mechanisms of telomerase regulation.
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Affiliation(s)
| | - Dorothy E. Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
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Abstract
Cervical carcinoma is one of the major causes of death in women worldwide. It is difficult to foresee a dramatic increase in cure rate even with the most optimal combination of cytotoxic drugs, surgery, and radiation; therefore, testing of molecular targeted therapies against this malignancy is highly desirable. Cervical cancer is a multistep process with accumulation of genetic and epigenetic alterations in regulatory genes, leading to activation of oncogenes and inactivation or loss of tumor suppressor genes (TSGs). In the last decade, in addition to genetic alterations, epigenetic inactivation of TSGs by promoter hypermethylation has been recognized as an important and alternative mechanism in tumorigenesis. In cervical cancer, epigenetic alterations can affect the expression of papillomavirus as well as host genes in relation to stages representing the multistep process of carcinogenesis. Here we discuss these epigenetic alterations in cervical cancer focusing on DNA methylation.
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40
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Jeon BG, Rho GJ, Betts DH, Petrik JJ, Favetta LA, King WA. Low levels of X-inactive specific transcript in somatic cell nuclear transfer embryos derived from female bovine freemartin donor cells. Sex Dev 2011; 6:151-9. [PMID: 22095296 DOI: 10.1159/000334050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The present study compared developmental potential, telomerase activity and transcript levels of X-linked genes (HPRT, MECP2, RPS4X, SLC25A6, XIAP, XIST and ZFX) in bovine somatic cell nuclear transfer (SCNT) embryos reconstructed with cells derived from a freemartin (female with a male co-twin) or from normal female cattle (control). The rates of cleavage, development to blastocyst and hatched blastocyst stage, and the mean numbers of total and inner cell mass cells in the freemartin SCNT embryos were not significantly different from those of control SCNT embryos (p > 0.05). The levels of telomerase activity analyzed by RQ-TRAP in the freemartin SCNT embryos were also similar to those of the normal SCNT embryos. Transcript levels of HPRT, MECP2, RPS4X and XIAP, measured by quantitative real-time RT-PCR, were not significantly different between the control and freemartin SCNT embryos (p > 0.05). However, the transcript levels of SLC25A6, XIST and ZFX were significantly decreased in the freemartin SCNT embryos compared to control SCNT embryos (p < 0.05). Transfer of 71 freemartin SCNT embryos to 22 recipient cows resulted in 4 (18%) pregnancies, which were lost between days 28 and 90 of gestation. Taken together, the present study demonstrates that the transcript levels of several X-linked genes, especially XIST, showed an aberrant pattern in the freemartin SCNT embryos, suggesting aberrant X inactivation in freemartin clones which may affect embryo survival.
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Affiliation(s)
- B G Jeon
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
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41
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Li CT, Hsiao YM, Wu TC, Lin YW, Yeh KT, Ko JL. Vorinostat, SAHA, represses telomerase activity via epigenetic regulation of telomerase reverse transcriptase in non-small cell lung cancer cells. J Cell Biochem 2011; 112:3044-53. [DOI: 10.1002/jcb.23229] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Horikawa I, Michishita E, Barrett JC. Regulation of hTERT transcription: a target of cellular and viral mechanisms for immortalization and carcinogenesis. Cytotechnology 2011; 45:23-32. [PMID: 19003240 DOI: 10.1007/s10616-004-5122-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Accepted: 09/21/2004] [Indexed: 01/30/2023] Open
Abstract
A hallmark of human cancer cells is immortal cell growth, which is associated with telomere maintenance by telomerase. The transcriptional regulation of the human telomerase reverse transcriptase (hTERT) gene is a major mechanism that negatively and positively controls telomerase activity in normal and cancer cells, respectively. A growing body of data suggests that various cellular and viral factors and pathways involved in cell senescence, immortalization and carcinogenesis act on the hTERT promoter. The activity of the hTERT promoter is regulated, either directly or through signaling pathways, by oncogene products (e.g., Myc and Ets families) and tumor suppressor proteins (e.g., BRCA1). Endogenous factors involved in the physiological repression of the hTERT gene have also been revealed by chromosome transfer experiments. The integration of viral genomes in the hTERT locus can lead to hTERT activation and telomerase induction. Here, we summarize these findings and pay special attention to recent findings with relevance to the endogenous regulatory mechanisms of hTERT transcription.
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Affiliation(s)
- Izumi Horikawa
- Laboratory of Biosystems and Cancer, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Building 37, Room 5046, Bethesda, MD, 20892, USA,
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Renaud S, Loukinov D, Alberti L, Vostrov A, Kwon YW, Bosman FT, Lobanenkov V, Benhattar J. BORIS/CTCFL-mediated transcriptional regulation of the hTERT telomerase gene in testicular and ovarian tumor cells. Nucleic Acids Res 2010; 39:862-73. [PMID: 20876690 PMCID: PMC3035453 DOI: 10.1093/nar/gkq827] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Telomerase activity, not detectable in somatic cells but frequently activated during carcinogenesis, confers immortality to tumors. Mechanisms governing expression of the catalytic subunit hTERT, the limiting factor for telomerase activity, still remain unclear. We previously proposed a model in which the binding of the transcription factor CTCF to the two first exons of hTERT results in transcriptional inhibition in normal cells. This inhibition is abrogated, however, by methylation of CTCF binding sites in 85% of tumors. Here, we showed that hTERT was unmethylated in testicular and ovarian tumors and in derivative cell lines. We demonstrated that CTCF and its paralogue, BORIS/CTCFL, were both present in the nucleus of the same cancer cells and bound to the first exon of hTERT in vivo. Moreover, exogenous BORIS expression in normal BORIS-negative cells was sufficient to activate hTERT transcription with an increasing number of cell passages. Thus, expression of BORIS was sufficient to allow hTERT transcription in normal cells and to counteract the inhibitory effect of CTCF in testicular and ovarian tumor cells. These results define an important contribution of BORIS to immortalization during tumorigenesis.
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Affiliation(s)
- Stéphanie Renaud
- Institute of Pathology, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland
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Oxidative stress and DNA methylation in prostate cancer. Obstet Gynecol Int 2010; 2010:302051. [PMID: 20671914 PMCID: PMC2910495 DOI: 10.1155/2010/302051] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Accepted: 05/12/2010] [Indexed: 12/20/2022] Open
Abstract
The protective effects of fruits, vegetables, and other foods on prostate cancer may be due to their antioxidant properties. An imbalance in the oxidative stress/antioxidant status is observed in prostate cancer patients. Genome oxidative damage in prostate cancer patients is associated with higher lipid peroxidation and lower antioxidant levels. Oxygen radicals are associated with different steps of carcinogenesis, including structural DNA damage, epigenetic changes, and protein and lipid alterations. Epigenetics affects genetic regulation, cellular differentiation, embryology, aging, cancer, and other diseases. DNA methylation is perhaps the most extensively studied epigenetic modification, which plays an important role in the regulation of gene expression and chromatin architecture, in association with histone modification and other chromatin-associated proteins. This review will provide a broad overview of the interplay of oxidative stress and DNA methylation, DNA methylation changes in regulation of gene expression, lifestyle changes for prostate cancer prevention, DNA methylation as biomarkers for prostate cancer, methods for detection of methylation, and clinical application of DNA methylation inhibitors for epigenetic therapy.
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45
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Salvatico J, Kim JH, Chung IK, Muller MT. Differentiation linked regulation of telomerase activity by Makorin-1. Mol Cell Biochem 2010; 342:241-50. [PMID: 20473778 DOI: 10.1007/s11010-010-0490-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Accepted: 05/04/2010] [Indexed: 01/23/2023]
Abstract
To understand telomere homeostasis, a significant aspect of cancer and growth control, it is important to examine telomerase induction as well as mechanisms of regulated elimination. Makorin-1 (MKRN1) was previously shown to be an E3 ubiquitin ligase that targets the telomerase catalytic subunit (hTERT) for proteasome processing (Kim et al., Genes Dev 19:776-781, 2005). In this study we examined expression and regulation of endogenous MKRN1 during the cell cycle and terminal differentiation. When WI-38 cells transition from active growth into a resting G1 state, basal levels of MKRN1 were found to increase by sixfold. In contrast, cancer cells typically contained low or in some cases undetectable levels of MKRN1 protein. HL-60 cells growing exponentially in culture contain no detectable MKRN1; however, following terminal differentiation, MKRN1 mRNA and protein levels are strongly up-regulated while hTERT mRNA, hTERC, and telomerase are shut down. The initial decrease in telomerase activity is due to a gradual reduction in transcription of the hTERT gene that occurs during the first 12 h of terminal differentiation. MKRN1 protein appears between 12 and 24 h and is attended by a more rapid loss of telomerase activity. As more MKRN1 protein accumulates, significantly less telomerase activity is seen. Addition of the proteasome inhibitor, MG132, reverses the loss of telomerase activity; therefore, reductions in telomerase activity are dynamic, ongoing, and correlated with robust up-regulation of MKRN1 as the cells terminally differentiate. The data are consistent with the idea that MKRN1 represents a telomerase elimination pathway to rapidly draw down the activity during differentiation or cell cycle arrest when telomerase action at chromosome ends is no longer necessary.
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Affiliation(s)
- Jose Salvatico
- Department of Molecular and Microbiology, College of Medicine, University of Central Florida, Orlando, FL 32826, USA
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46
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Li W, Tao KX. Advances in research of the epigenetic regulation of hTERT expression. Shijie Huaren Xiaohua Zazhi 2010; 18:1026-1031. [DOI: 10.11569/wcjd.v18.i10.1026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Human telomerase reverse transcriptase (hTERT), the catalytic subunit of the telomerase, is the rate-limiting component for telomerase activity. Epigenetic regulation of gene transcription does not change DNA sequences but depends on chemical modification of either DNA or histones or non-coding RNAs. Epigenetic regulation is inheritable and plays an important role in controlling gene expression. The expression of hTERT may also be subjected to epigenetic regulation, such as DNA methylation, histone acetylation and methylation, and non-coding RNAs.
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Promoter hypermethylation of FBXO32, a novel TGF-beta/SMAD4 target gene and tumor suppressor, is associated with poor prognosis in human ovarian cancer. J Transl Med 2010; 90:414-25. [PMID: 20065949 PMCID: PMC2829100 DOI: 10.1038/labinvest.2009.138] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Resistance to TGF-beta is frequently observed in ovarian cancer, and disrupted TGF-beta/SMAD4 signaling results in the aberrant expression of downstream target genes in the disease. Our previous study showed that ADAM19, a SMAD4 target gene, is downregulated through epigenetic mechanisms in ovarian cancer with aberrant TGF-beta/SMAD4 signaling. In this study, we investigated the mechanism of downregulation of FBXO32, another SMAD4 target gene, and the clinical significance of the loss of FBXO32 expression in ovarian cancer. Expression of FBXO32 was observed in the normal ovarian surface epithelium, but not in ovarian cancer cell lines. FBXO32 methylation was observed in ovarian cancer cell lines displaying constitutive TGF-beta/SMAD4 signaling, and epigenetic drug treatment restored FBXO32 expression in ovarian cancer cell lines regardless of FBXO32 methylation status, suggesting that epigenetic regulation of this gene in ovarian cancer may be a common event. In advanced-stage ovarian tumors, a significant (29.3%; P<0.05) methylation frequency of FBXO32 was observed and the association between FBXO32 methylation and shorter progression-free survival was significant, as determined by both Kaplan-Meier analysis (P<0.05) and multivariate Cox regression analysis (hazard ratio: 1.003, P<0.05). Reexpression of FBXO32 markedly reduced proliferation of a platinum-resistant ovarian cancer cell line both in vitro and in vivo, due to increased apoptosis of the cells, and resensitized ovarian cancer cells to cisplatin. In conclusion, the novel tumor suppressor FBXO32 is epigenetically silenced in ovarian cancer cell lines with disrupted TGF-beta/SMAD4 signaling, and FBXO32 methylation status predicts survival in patients with ovarian cancer.
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Zhu J, Zhao Y, Wang S. Chromatin and epigenetic regulation of the telomerase reverse transcriptase gene. Protein Cell 2010; 1:22-32. [PMID: 21203995 DOI: 10.1007/s13238-010-0014-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Accepted: 12/03/2009] [Indexed: 01/30/2023] Open
Abstract
Telomerase expression and telomere maintenance are critical for long-term cell proliferation and survival, and they play important roles in development, aging, and cancer. Cumulating evidence has indicated that regulation of the rate-limiting subunit of human telomerase reverse transcriptase gene (hTERT) is a complex process in normal cells and many cancer cells. In addition to a number of transcriptional activators and repressors, the chromatin environment and epigenetic status of the endogenous hTERT locus are also pivotal for its regulation in normal human somatic cells and in tumorigenesis.
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Affiliation(s)
- Jiyue Zhu
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
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Epigenetic plasticity of hTERT gene promoter determines retinoid capacity to repress telomerase in maturation-resistant acute promyelocytic leukemia cells. Leukemia 2010; 24:613-22. [PMID: 20072159 DOI: 10.1038/leu.2009.283] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The expression of hTERT gene, encoding the catalytic subunit of telomerase, is a feature of most cancer cells. Changes in the chromatin environment of its promoter and binding of transcriptional factors have been reported in differentiating cells when its transcription is repressed. However, it is not clear whether these changes are directly involved in this repression or only linked to differentiation. In a maturation-resistant acute promyelocytic leukemia (APL) cell line (NB4-LR1), we have previously identified a new pathway of retinoid-induced hTERT repression independent of differentiation. Using a variant of this cell line (NB4-LR1(SFD)), which resists to this repression, we show that although distinct patterns of histone modifications and transcription factor binding at the proximal domain of hTERT gene promoter could concur to modulate its expression, this region is not sufficient to the on/off switch of hTERT by retinoids. DNA methylation analysis of the hTERT promoter led to the identification of two distinct functional domains, a proximal one, fully unmethylated in both cell lines, and a distal one, significantly methylated in NB4-LR1(SFD) cells, whose methylation was further re-enforced by retinoid treatment. Interestingly, we showed that the binding to this distal domain of a known hTERT repressor, WT1, was defective only in NB4-LR1(SFD) cells. We propose that epigenetic modifications targeting this distal region could modulate the binding of hTERT repressors and account either for hTERT reactivation and resistance to retinoid-induced hTERT downregulation.
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50
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Chebel A, Rouault JP, Urbanowicz I, Baseggio L, Chien WW, Salles G, Ffrench M. Transcriptional activation of hTERT, the human telomerase reverse transcriptase, by nuclear factor of activated T cells. J Biol Chem 2010; 284:35725-34. [PMID: 19843528 DOI: 10.1074/jbc.m109.009183] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Telomerase is essential for telomere maintenance, and its activation is thought to be a critical step in cellular immortalization and tumorigenesis. Human telomerase reverse transcriptase (hTERT) is a major component of telomerase activity. We show here that hTERT is expressed soon after lymphocyte activation and that its expression is inhibited by rapamycin, wortmannin, and FK506, which was the most potent inhibitor. These results suggest a potential role for the transcription factor nuclear factor of activated T cells (NFAT) in the regulation of hTERT expression. Five putative NFAT-binding sites were identified in the hTERT promoter. In luciferase assays, the hTERT promoter was activated by overexpressed NFAT1. Moreover, serial deletions revealed that the promoter activation was mainly due to a -40 NFAT1-binding site flanked by two SP1-binding sites. Mutation of the -40 NFAT-binding site caused a 53% reduction in the transcriptional activity of hTERT promoter. Simultaneous mutations of the -40 NFAT-responsive element together with one or both SP1-binding sites led to a more dramatic decrease in luciferase activity than single mutations, suggesting a functional synergy between NFAT1 and SP1 in hTERT transcriptional regulation. NFAT1 overexpression in MCF7 and Jurkat cell lines induced an increase in endogenous hTERT mRNA expression. Inversely, its down-regulation was induced by NFAT1 silencing. Furthermore, chromatin immunoprecipitation assay demonstrated that NFAT1 directly binds to two sites (-40 and -775) in the endogenous hTERT promoter. Thus, we show for the first time the direct involvement of NFAT1 in the transcriptional regulation of hTERT.
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Affiliation(s)
- Amel Chebel
- Université Lyon 1, CNRS UMR 5239, Ecole Normale Supérieure (ENS), Université Claude Bernard, Hospices Civils de Lyon, Faculté Lyon-Sud, Oullins 69921
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