1
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Kikuchi AT, Umetsu S, Joseph N, Kakar S. Genomic Analysis in the Categorization of Poorly Differentiated Primary Liver Carcinomas. Am J Surg Pathol 2023; 47:1207-1218. [PMID: 37661782 DOI: 10.1097/pas.0000000000002116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
A subset of primary liver carcinomas (PLCs) cannot be classified as hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma (iCCA) based on morphology and immunohistochemistry (IHC). This includes tumors with morphology suggestive of HCC but lacking hepatocellular marker expression, tumors with ambiguous morphology characterized by co-expression of hepatocellular and cholangiocytic markers, and undifferentiated pleomorphic carcinomas with no discernible line of differentiation on morphology or IHC. This study examines the role of genomic analysis in the categorization of these tumors. Genomic analysis was performed on 16 PLCs that could not be definitely classified as HCC or iCCA based on morphology and IHC using a capture-based next-generation sequencing assay (n=15) or single gene mutational analysis (n=1). Genomic alterations in TERT promoter were seen in 9/16 cases (56%) and strongly favored HCC. Genomic alterations favoring iCCA were seen in 5/16 cases (31%) and included mutations in IDH1 , PBRM1 , BAP1 , and ERBB2 , as well as FGFR2 fusion. Genomic changes were helpful in classifying 14/16 (87%) PLCs. Though not specific, these genomic alterations can provide valuable diagnostic clues in selected morphologically and immunohistochemically unclassifiable cases. Given the important differences in management between HCC and iCCA, routine use of genomic analysis in diagnostically challenging settings should be considered.
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Affiliation(s)
- Alexander T Kikuchi
- Department of Pathology, University of California San Francisco, San Francisco, CA
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2
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Ali JH, Walter M. Combining old and new concepts in targeting telomerase for cancer therapy: transient, immediate, complete and combinatory attack (TICCA). Cancer Cell Int 2023; 23:197. [PMID: 37679807 PMCID: PMC10483736 DOI: 10.1186/s12935-023-03041-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 08/25/2023] [Indexed: 09/09/2023] Open
Abstract
Telomerase can overcome replicative senescence by elongation of telomeres but is also a specific element in most cancer cells. It is expressed more vastly than any other tumor marker. Telomerase as a tumor target inducing replicative immortality can be overcome by only one other mechanism: alternative lengthening of telomeres (ALT). This limits the probability to develop resistance to treatments. Moreover, telomerase inhibition offers some degree of specificity with a low risk of toxicity in normal cells. Nevertheless, only one telomerase antagonist reached late preclinical studies. The underlying causes, the pitfalls of telomerase-based therapies, and future chances based on recent technical advancements are summarized in this review. Based on new findings and approaches, we propose a concept how long-term survival in telomerase-based cancer therapies can be significantly improved: the TICCA (Transient Immediate Complete and Combinatory Attack) strategy.
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Affiliation(s)
- Jaber Haj Ali
- Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
- Institute of Clinical Chemistry and Laboratory Medicine, Universitätsmedizin Rostock, Ernst-Heydemann-Straße 6, 18057, Rostock, Germany
| | - Michael Walter
- Institute of Clinical Chemistry and Laboratory Medicine, Universitätsmedizin Rostock, Ernst-Heydemann-Straße 6, 18057, Rostock, Germany.
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3
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Yang L, Li N, Wang M, Zhang YH, Yan LD, Zhou W, Yu ZQ, Peng XC, Cai J. Tumorigenic effect of TERT and its potential therapeutic target in NSCLC (Review). Oncol Rep 2021; 46:182. [PMID: 34278503 DOI: 10.3892/or.2021.8133] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 05/25/2021] [Indexed: 12/24/2022] Open
Abstract
Non‑small cell lung cancer (NSCLC), which accounts for ~85% of all lung cancer cases, is commonly diagnosed at an advanced stage and has a high patient mortality rate. Despite the increasing availability of treatment strategies, the prognosis of patients with NSCLC remains poor, with a low 5‑year survival rate. This poor prognosis may be associated with the tumor heterogeneity of NSCLC, as well as its acquisition and intrinsic resistance to therapeutic drugs. It has been suggested that combination therapy with telomerase inhibition may be an effective strategy for the treatment of drug‑sensitive and drug‑resistant types of cancer. Telomerase is the key enzyme for cell survival, and ~90% of human cancers maintain telomeres by activating telomerase, which is driven by the upregulation of telomerase reverse transcriptase (TERT). Several mechanisms of telomerase reactivation have been described in a variety of cancer types, including TERT promoter mutation, epigenetic modifications via a TERT promoter, TERT amplification, and TERT rearrangement. The aim of the present study was to comprehensively review telomerase activity and its association with the clinical characteristics and prognosis of NSCLC, as well as analyze the potential mechanism via which TERT activates telomerase and determine its potential clinical application in NSCLC. More importantly, current treatment strategies targeting TERT in NSCLC have been summarized with the aim to promote discovery of novel strategies for the future treatment of NSCLC.
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Affiliation(s)
- Liu Yang
- Department of Oncology, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434023, P.R. China
| | - Na Li
- Department of Oncology, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434023, P.R. China
| | - Meng Wang
- Department of Oncology, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434023, P.R. China
| | - Yan-Hua Zhang
- Department of Oncology, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434023, P.R. China
| | - Lu-Da Yan
- Department of Oncology, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434023, P.R. China
| | - Wen Zhou
- Department of Oncology, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434023, P.R. China
| | - Zhi-Qiong Yu
- Department of Oncology, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434023, P.R. China
| | - Xiao-Chun Peng
- Laboratory of Oncology, Center for Molecular Medicine, Yangtze University, Jingzhou, Hubei 434023, P.R. China
| | - Jun Cai
- Department of Oncology, First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434023, P.R. China
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4
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in der Stroth L, Tharehalli U, Günes C, Lechel A. Telomeres and Telomerase in the Development of Liver Cancer. Cancers (Basel) 2020; 12:E2048. [PMID: 32722302 PMCID: PMC7464754 DOI: 10.3390/cancers12082048] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/16/2020] [Accepted: 07/22/2020] [Indexed: 02/07/2023] Open
Abstract
Liver cancer is one of the most common cancer types worldwide and the fourth leading cause of cancer-related death. Liver carcinoma is distinguished by a high heterogeneity in pathogenesis, histopathology and biological behavior. Dysregulated signaling pathways and various gene mutations are frequent in hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA), which represent the two most common types of liver tumors. Both tumor types are characterized by telomere shortening and reactivation of telomerase during carcinogenesis. Continuous cell proliferation, e.g., by oncogenic mutations, can cause extensive telomere shortening in the absence of sufficient telomerase activity, leading to dysfunctional telomeres and genome instability by breakage-fusion-bridge cycles, which induce senescence or apoptosis as a tumor suppressor mechanism. Telomerase reactivation is required to stabilize telomere functionality and for tumor cell survival, representing a genetic risk factor for the development of liver cirrhosis and liver carcinoma. Therefore, telomeres and telomerase could be useful targets in hepatocarcinogenesis. Here, we review similarities and differences between HCC and iCCA in telomere biology.
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Affiliation(s)
- Lena in der Stroth
- Department of Internal Medicine I, University Hospital Ulm, 89081 Ulm, Germany; (L.i.d.S.); (U.T.)
| | - Umesh Tharehalli
- Department of Internal Medicine I, University Hospital Ulm, 89081 Ulm, Germany; (L.i.d.S.); (U.T.)
| | - Cagatay Günes
- Department of Urology, University Hospital Ulm, 89081 Ulm, Germany;
| | - André Lechel
- Department of Internal Medicine I, University Hospital Ulm, 89081 Ulm, Germany; (L.i.d.S.); (U.T.)
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5
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Berrino E, Angeli A, Zhdanov DD, Kiryukhina AP, Milaneschi A, De Luca A, Bozdag M, Carradori S, Selleri S, Bartolucci G, Peat TS, Ferraroni M, Supuran CT, Carta F. Azidothymidine "Clicked" into 1,2,3-Triazoles: First Report on Carbonic Anhydrase-Telomerase Dual-Hybrid Inhibitors. J Med Chem 2020; 63:7392-7409. [PMID: 32463228 PMCID: PMC8154556 DOI: 10.1021/acs.jmedchem.0c00636] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
Cancer cells rely on the enzyme telomerase
(EC 2.7.7.49) to promote
cellular immortality. Telomerase inhibitors (i.e., azidothymidine)
can represent promising antitumor agents, although showing high toxicity
when administered alone. Better outcomes were observed within a multipharmacological
approach instead. In this context, we exploited the validated antitumor
targets carbonic anhydrases (CAs; EC 4.2.1.1) IX and XII to attain
the first proof of concept on CA–telomerase dual-hybrid inhibitors.
Compounds 1b, 7b, 8b, and 11b showed good in vitro
inhibition potency against the CAs IX and XII, with KI values in the low nanomolar range, and strong antitelomerase
activity in PC-3 and HT-29 cells (IC50 values ranging from
5.2 to 9.1 μM). High-resolution X-ray crystallography on selected
derivatives in the adduct with hCA II as a model study allowed to
determine their binding modes and thus to set the structural determinants
necessary for further development of compounds selectively targeting
the tumoral cells.
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Affiliation(s)
- Emanuela Berrino
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Andrea Angeli
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Dmitry D Zhdanov
- Institute of Biomedical Chemistry, Pogodinskaya st. 10/8, 119121 Moscow, Russia.,Peoples Friendship University of Russia (RUDN University), Miklukho-Maklaya st. 6, 117198 Moscow, Russia
| | - Anna P Kiryukhina
- Institute of Biomedical Chemistry, Pogodinskaya st. 10/8, 119121 Moscow, Russia
| | - Andrea Milaneschi
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Alessandro De Luca
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Murat Bozdag
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Simone Carradori
- Department of Pharmacy, "G. d'Annunzio" University of Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy
| | - Silvia Selleri
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Gianluca Bartolucci
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Thomas S Peat
- CSIRO, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Marta Ferraroni
- Dipartimento di Chimica "Ugo Schiff", Università di Firenze, Via della Lastruccia 3-13, 50019 Sesto Fiorentino (Florence), Italy
| | - Claudiu T Supuran
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Fabrizio Carta
- NEUROFARBA Department, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino (Florence), Italy
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6
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Ako S, Nouso K, Kinugasa H, Matsushita H, Terasawa H, Adachi T, Wada N, Takeuchi Y, Mandai M, Onishi H, Ikeda F, Shiraha H, Takaki A, Fujioka S, Mimura T, Okada H. Human Telomerase Reverse Transcriptase Gene Promoter Mutation in Serum of Patients with Hepatocellular Carcinoma. Oncology 2020; 98:311-317. [PMID: 32135540 DOI: 10.1159/000506135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 01/16/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND Mutations in the human telomerase reverse transcriptase (hTERT) gene promoter have been reported in hepatocellular carcinoma (HCC); however, analyses of these mutations in liquid biopsies have been technically difficult because of the high GC content of the regions of interest within this promoter. We evaluated the feasibility and prognostic value of hTERT promoter mutations identified in circulating cell-free DNA (cfDNA) from the serum of patients with HCC. OBJECTIVE A cohort of HCC patients (n = 36) who were curatively treated by surgical resection between June 2003 and September 2014 were enrolled in this study. METHODS The presence of hTERT promoter mutations in cfDNA from the patients' serum was analyzed via modified droplet digital polymerase chain reaction, and associations were sought between specific promoter mutations and patients' disease-free survival (DFS). RESULTS The G>A hTERT mutation at -124 bp was detected in the serum of 25 patients (69%). Although no marked differences were observed between the characteristics of the serum mutation-positive and serum mutation-negative patient groups, the DFS of patients with the mutation was significantly shorter than that of the serum mutation-negative patients (p = 0.02). Among 18 clinicopathologic and background liver factors examined, the presence of the -124 bp G>A mutation was an independent and significant predictor of patients' DFS (hazard ratio = 3.01, 95% confidence interval 1.11-10.5, p = 0.03) in multivariate analyses. CONCLUSIONS The -124 bp G>A hTERT promoter mutation was observed in the serum of 69% of HCC patients who underwent surgical resection and was an independent predictor of disease progression in HCC.
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Affiliation(s)
- Soichiro Ako
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Kazuhiro Nouso
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan, .,Department of Gastroenterology, Okayama City Hospital, Okayama, Japan,
| | - Hideaki Kinugasa
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Hiroshi Matsushita
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.,Department of Gastroenterology, Okayama City Hospital, Okayama, Japan
| | - Hiroyuki Terasawa
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Takuya Adachi
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Nozomu Wada
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Yasuto Takeuchi
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Mari Mandai
- Department of Internal Medicine, Okayama Saiseikai General Hospital, Okayama, Japan
| | - Hideki Onishi
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Fusao Ikeda
- Department of Internal Medicine, Okayama Saiseikai General Hospital, Okayama, Japan
| | - Hidenori Shiraha
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Akinobu Takaki
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Shinichi Fujioka
- Department of Internal Medicine, Okayama Saiseikai General Hospital, Okayama, Japan
| | - Tetsushige Mimura
- Department of Surgery, Okayama Saiseikai General Hospital, Okayama, Japan
| | - Hiroyuki Okada
- Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
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7
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Hussein NAEM, El-Toukhy MAEF, Kazem AH, Ali MES, Ahmad MAER, Ghazy HMR, El-Din AMG. Protective and therapeutic effects of cannabis plant extract on liver cancer induced by dimethylnitrosamine in mice. ALEXANDRIA JOURNAL OF MEDICINE 2019. [DOI: 10.1016/j.ajme.2014.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Neveen Abd El Moneim Hussein
- Applied Medical Chemistry, Applied Medical Chemistry Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Mervat Abd El-Fattah El-Toukhy
- Applied Medical Chemistry, Applied Medical Chemistry Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Amany Hussein Kazem
- Department of Pathology, Medical Research Institute, University of Alexandria, Alexandria, Egypt
| | - Mahmoud El-Said Ali
- Toxicology Department, Forensic Science College, Naif Arab University for Security Sciences, Saudi Arabia
| | | | - Hossam Mahmoud Rashad Ghazy
- Applied Medical Chemistry, Applied Medical Chemistry Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Ahmed Mohamed Gamal El-Din
- Applied Medical Chemistry, Applied Medical Chemistry Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
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8
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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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9
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Islam B, Stadlbauer P, Gil-Ley A, Pérez-Hernández G, Haider S, Neidle S, Bussi G, Banas P, Otyepka M, Sponer J. Exploring the Dynamics of Propeller Loops in Human Telomeric DNA Quadruplexes Using Atomistic Simulations. J Chem Theory Comput 2017; 13:2458-2480. [PMID: 28475322 PMCID: PMC5514396 DOI: 10.1021/acs.jctc.7b00226] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
![]()
We
have carried out a series of extended unbiased molecular dynamics
(MD) simulations (up to 10 μs long, ∼162 μs in
total) complemented by replica-exchange with the collective variable
tempering (RECT) approach for several human telomeric DNA G-quadruplex
(GQ) topologies with TTA propeller loops. We used different AMBER
DNA force-field variants and also processed simulations by Markov
State Model (MSM) analysis. The slow conformational transitions in
the propeller loops took place on a scale of a few μs, emphasizing
the need for long simulations in studies of GQ dynamics. The propeller
loops sampled similar ensembles for all GQ topologies and for all
force-field dihedral-potential variants. The outcomes of standard
and RECT simulations were consistent and captured similar spectrum
of loop conformations. However, the most common crystallographic loop
conformation was very unstable with all force-field versions. Although
the loss of canonical γ-trans state of the
first propeller loop nucleotide could be related to the indispensable
bsc0 α/γ dihedral potential, even supporting this particular
dihedral by a bias was insufficient to populate the experimentally
dominant loop conformation. In conclusion, while our simulations were
capable of providing a reasonable albeit not converged sampling of
the TTA propeller loop conformational space, the force-field description
still remained far from satisfactory.
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Affiliation(s)
- Barira Islam
- Institute of Biophysics, Academy of Sciences of the Czech Republic , Královopolská 135, 612 65 Brno, Czech Republic
| | - Petr Stadlbauer
- Institute of Biophysics, Academy of Sciences of the Czech Republic , Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University , 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic
| | - Alejandro Gil-Ley
- Scuola Internazionale Superiore di Studi Avanzati, Via Bonomea 265, 34136 Trieste, Italy
| | - Guillermo Pérez-Hernández
- Department for Mathematics and Computer Science, Freie Universität Berlin , Arnimallee 6, Berlin 14195, Germany
| | - Shozeb Haider
- UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, U.K
| | - Stephen Neidle
- UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, U.K
| | - Giovanni Bussi
- Scuola Internazionale Superiore di Studi Avanzati, Via Bonomea 265, 34136 Trieste, Italy
| | - Pavel Banas
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University , 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic
| | - Michal Otyepka
- Institute of Biophysics, Academy of Sciences of the Czech Republic , Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University , 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic
| | - Jiri Sponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic , Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University , 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic
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10
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Hepatitis C virus and schistosomiasis as a causative factor for hTERT amplification in hepatocellular carcinoma. GENE REPORTS 2016. [DOI: 10.1016/j.genrep.2016.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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11
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Jäger K, Walter M. Therapeutic Targeting of Telomerase. Genes (Basel) 2016; 7:genes7070039. [PMID: 27455328 PMCID: PMC4962009 DOI: 10.3390/genes7070039] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 06/16/2016] [Accepted: 06/24/2016] [Indexed: 12/20/2022] Open
Abstract
Telomere length and cell function can be preserved by the human reverse transcriptase telomerase (hTERT), which synthesizes the new telomeric DNA from a RNA template, but is normally restricted to cells needing a high proliferative capacity, such as stem cells. Consequently, telomerase-based therapies to elongate short telomeres are developed, some of which have successfully reached the stage I in clinical trials. Telomerase is also permissive for tumorigenesis and 90% of all malignant tumors use telomerase to obtain immortality. Thus, reversal of telomerase upregulation in tumor cells is a potential strategy to treat cancer. Natural and small-molecule telomerase inhibitors, immunotherapeutic approaches, oligonucleotide inhibitors, and telomerase-directed gene therapy are useful treatment strategies. Telomerase is more widely expressed than any other tumor marker. The low expression in normal tissues, together with the longer telomeres in normal stem cells versus cancer cells, provides some degree of specificity with low risk of toxicity. However, long term telomerase inhibition may elicit negative effects in highly-proliferative cells which need telomerase for survival, and it may interfere with telomere-independent physiological functions. Moreover, only a few hTERT molecules are required to overcome senescence in cancer cells, and telomerase inhibition requires proliferating cells over a sufficient number of population doublings to induce tumor suppressive senescence. These limitations may explain the moderate success rates in many clinical studies. Despite extensive studies, only one vaccine and one telomerase antagonist are routinely used in clinical work. For complete eradication of all subpopulations of cancer cells a simultaneous targeting of several mechanisms will likely be needed. Possible technical improvements have been proposed including the development of more specific inhibitors, methods to increase the efficacy of vaccination methods, and personalized approaches. Telomerase activation and cell rejuvenation is successfully used in regenerative medicine for tissue engineering and reconstructive surgery. However, there are also a number of pitfalls in the treatment with telomerase activating procedures for the whole organism and for longer periods of time. Extended cell lifespan may accumulate rare genetic and epigenetic aberrations that can contribute to malignant transformation. Therefore, novel vector systems have been developed for a 'mild' integration of telomerase into the host genome and loss of the vector in rapidly-proliferating cells. It is currently unclear if this technique can also be used in human beings to treat chronic diseases, such as atherosclerosis.
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Affiliation(s)
- Kathrin Jäger
- Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin 13353, Germany.
| | - Michael Walter
- Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin 13353, Germany.
- Labor Berlin-Charité Vivantes Services GmbH, Sylter Str. 2, Berlin 13353, Germany.
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12
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Yaswen P, MacKenzie KL, Keith WN, Hentosh P, Rodier F, Zhu J, Firestone GL, Matheu A, Carnero A, Bilsland A, Sundin T, Honoki K, Fujii H, Georgakilas AG, Amedei A, Amin A, Helferich B, Boosani CS, Guha G, Ciriolo MR, Chen S, Mohammed SI, Azmi AS, Bhakta D, Halicka D, Niccolai E, Aquilano K, Ashraf SS, Nowsheen S, Yang X. Therapeutic targeting of replicative immortality. Semin Cancer Biol 2015; 35 Suppl:S104-S128. [PMID: 25869441 PMCID: PMC4600408 DOI: 10.1016/j.semcancer.2015.03.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 03/06/2015] [Accepted: 03/13/2015] [Indexed: 12/15/2022]
Abstract
One of the hallmarks of malignant cell populations is the ability to undergo continuous proliferation. This property allows clonal lineages to acquire sequential aberrations that can fuel increasingly autonomous growth, invasiveness, and therapeutic resistance. Innate cellular mechanisms have evolved to regulate replicative potential as a hedge against malignant progression. When activated in the absence of normal terminal differentiation cues, these mechanisms can result in a state of persistent cytostasis. This state, termed “senescence,” can be triggered by intrinsic cellular processes such as telomere dysfunction and oncogene expression, and by exogenous factors such as DNA damaging agents or oxidative environments. Despite differences in upstream signaling, senescence often involves convergent interdependent activation of tumor suppressors p53 and p16/pRB, but can be induced, albeit with reduced sensitivity, when these suppressors are compromised. Doses of conventional genotoxic drugs required to achieve cancer cell senescence are often much lower than doses required to achieve outright cell death. Additional therapies, such as those targeting cyclin dependent kinases or components of the PI3K signaling pathway, may induce senescence specifically in cancer cells by circumventing defects in tumor suppressor pathways or exploiting cancer cells’ heightened requirements for telomerase. Such treatments sufficient to induce cancer cell senescence could provide increased patient survival with fewer and less severe side effects than conventional cytotoxic regimens. This positive aspect is countered by important caveats regarding senescence reversibility, genomic instability, and paracrine effects that may increase heterogeneity and adaptive resistance of surviving cancer cells. Nevertheless, agents that effectively disrupt replicative immortality will likely be valuable components of new combinatorial approaches to cancer therapy.
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Affiliation(s)
- Paul Yaswen
- Life Sciences Division, Lawrence Berkeley National Lab, Berkeley, CA, United States.
| | - Karen L MacKenzie
- Children's Cancer Institute Australia, Kensington, New South Wales, Australia.
| | | | | | | | - Jiyue Zhu
- Washington State University College of Pharmacy, Pullman, WA, United States.
| | | | | | - Amancio Carnero
- Instituto de Biomedicina de Sevilla, HUVR, Consejo Superior de Investigaciones Cientificas, Universdad de Sevilla, Seville, Spain.
| | | | | | | | | | | | | | - Amr Amin
- United Arab Emirates University, Al Ain, United Arab Emirates; Cairo University, Cairo, Egypt
| | - Bill Helferich
- University of Illinois at Urbana Champaign, Champaign, IL, United States
| | | | - Gunjan Guha
- SASTRA University, Thanjavur, Tamil Nadu, India
| | | | - Sophie Chen
- Ovarian and Prostate Cancer Research Trust, Guildford, Surrey, United Kingdom
| | | | - Asfar S Azmi
- Karmanos Cancer Institute, Wayne State University, Detroit, MI, United States
| | | | | | | | | | - S Salman Ashraf
- United Arab Emirates University, Al Ain, United Arab Emirates; Cairo University, Cairo, Egypt
| | | | - Xujuan Yang
- University of Illinois at Urbana Champaign, Champaign, IL, United States
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13
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hTERT gene amplification and clinical significance in pleural effusions of patients with lung cancer. Clin Lung Cancer 2012; 13:494-9. [PMID: 22464057 DOI: 10.1016/j.cllc.2012.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 01/16/2012] [Accepted: 01/23/2012] [Indexed: 11/22/2022]
Abstract
PATIENTS AND METHODS Human telomerase reverse transcriptase (hTERT) gene amplification was detected in pleural effusions of patients with lung cancer (n = 69) and in patients with benign lung disease (n = 46) when using a quantitative polymerase chain reaction (qPCR) technique. RESULTS hTERT gene relative copy numbers were significantly higher in effusions from patients with malignant, adenocarcinoma and small-cell lung cancer than in effusions from patients with benign lung disease (P < .01). By using a threshold value of 1.39, hTERT gene amplification was significantly more frequent in malignant effusions compared with benign effusions and more likely to be positive for malignant effusions, compared with cytology (P < .01). The diagnostic performance of qPCR of hTERT gene amplification was significantly higher than that of cytology, in terms of sensitivity (91.3% vs. 56.5%), negative predictive value (87.8% vs. 60.5%), and accuracy (92.2% vs. 73.9%). CONCLUSIONS Detecting hTERT gene amplification by qPCR appears suitable for distinguishing carcinoma cells from reactive mesothelial cells in pleural effusions. hTERT gene amplification was more sensitive than cytology and may be useful for diagnosing pleural micrometastases.
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Li ZH, Tang QB, Wang J, Zhou L, Huang WL, Liu RY, Chen RF. Hepatitis C virus core protein induces malignant transformation of biliary epithelial cells by activating nuclear factor-kappaB pathway. J Gastroenterol Hepatol 2010; 25:1315-20. [PMID: 20594262 DOI: 10.1111/j.1440-1746.2009.06201.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
UNLABELLED In an earlier study, we found that hepatitis C virus core protein, HCV-C, participated in the malignant transformation of HCV-C transfected normal human biliary epithelial (hBE) cells by activating telomerase. Here we further investigated the signaling of the malignant transformation. METHODS Reverse transcription-polymerase chain reaction (RT-PCR), western blotting and immunoprecipitation were used to analyze the expression of HCV-C, human telomerase reverse transcriptase (hTERT), nuclear factor-kappaB (NF-kappaB) and NF-kappaB inhibitor alpha (IkappaBalpha) genes and the phosphorylation level of IkappaBalpha protein. Electrophoretic mobility shift assays (EMSA) and NF-kappaB-linked luciferase reporter assays were carried out to measure NF-kappaB activity. RESULTS The expression of HCV-C and hTERT was detected only in HCV-C-transfected hBE (hBE-HCV-C) cells but not in vector-transfected or parental hBE cells. More NF-kappaB protein accumulated in nuclear extracts of hBE-HCV-C cells rather than in those of control cells, though total NF-kappaB protein level showed no difference among these cells. DNA binding activity of NF-kappaB and the NF-kappaB-linked luciferase activity were much higher in HCV-C-transfected hBE cells than those in vector- or non-transfected hBE cells. In addition, the IkappaBalpha phosphorylation level, but not the IkappaBalpha mRNA or protein levels, was increased after HCV-C transfection. CONCLUSIONS Hepatitis C virus core protein activates NF-kappaB pathway in hBE cells by increasing the phosphorylation of IkappaBalpha. The pathway may be responsible for HCV-C-induced malignant transformation of hBE cells.
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Affiliation(s)
- Zhi-Hua Li
- Department of Oncology, Affiliated Second Hospital, Sun Yat-sen University, Guangzhou, China
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15
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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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16
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Zhao Y, Wang S, Popova EY, Grigoryev SA, Zhu J. Rearrangement of upstream sequences of the hTERT gene during cellular immortalization. Genes Chromosomes Cancer 2010; 48:963-74. [PMID: 19672873 DOI: 10.1002/gcc.20698] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Telomerase expression, resulting from transcriptional activation of the hTERT gene, allows cells to acquire indefinite proliferative potential during cellular immortalization and tumorigenesis. However, mechanisms of hTERT gene activation in many immortal cell lines and cancer cells are poorly understood. Here, we report our studies on hTERT activation using genetically related pairs of telomerase-negative (Tel(-)) and -positive (Tel(+)) fibroblast lines. First, whereas transiently transfected plasmid reporters did not recapitulate the endogenous hTERT promoter, the promoter in chromosomally integrated bacterial artificial chromosome (BAC) reporters was activated in a subset of Tel(+) cells, indicating that activation of the hTERT promoter required native chromatin context and/or distal regulatory elements. Second, the hTERT gene, located near the telomere of chromosome 5p, was translocated in all three Tel(+) cell lines but not in their parental precrisis cells and Tel(-) immortal siblings. The breakage points were mapped to regions upstream of the hTERT promoter, indicating that the hTERT gene was the target of these chromosomal rearrangements. In two Tel(+) cell lines, translocation of the endogenous hTERT gene appeared to be the major mechanism of its activation as the activity of hTERT promoter in many chromosomally integrated BAC reporters, with intact upstream and downstream neighboring loci, remained relatively low. Therefore, our results suggest that rearrangement of upstream sequences is an important new mechanism of hTERT promoter activation during cellular immortalization. The chromosomal rearrangements likely occurred during cellular crisis and facilitated by telomere dysfunction. Such translocations allowed the hTERT promoter to escape from the native condensed chromatin environment.
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Affiliation(s)
- Yuanjun Zhao
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA, USA
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17
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Cao Y, Bryan TM, Reddel RR. Increased copy number of the TERT and TERC telomerase subunit genes in cancer cells. Cancer Sci 2008; 99:1092-9. [PMID: 18482052 PMCID: PMC11158516 DOI: 10.1111/j.1349-7006.2008.00815.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Telomerase is a ribonucleoprotein enzyme complex that adds telomeric repeats to the ends of chromosomes. The core telomerase components are the telomerase reverse transcriptase (TERT) catalytic subunit, and the telomerase RNA (TR) template subunit. In most cancers, telomerase is expressed at levels that are substantially higher than in normal cells. A known consequence of telomerase up-regulation which is considered to play a critical role in oncogenesis is maintenance of telomere length, and thus evasion by cancer cells of the normal limits on proliferation that are associated with the steady decrease in telomere length that accompanies proliferation of normal cells. It has also been suggested that telomerase up-regulation confers other advantages on cancer cells independent of its enzymatic activity. The mechanisms responsible for up-regulation of telomerase in cancer are incompletely understood. Here we review evidence suggesting that this frequently results from increased copy number of the genes encoding telomerase components. The TERT gene is located at human chromosome band 5p15.33, and the telomerase RNA component (TERC) gene that encodes TR is at 3q26.3. Chromosomal gains and gene amplifications involving chromosome arms 5p and 3q are among the most frequent in human tumors. Increased TERT and TERC gene dosage has been detected frequently in a variety of human cancers, and clonal evolution of cells with increased TERT or TERC copy number has been observed, suggesting a growth advantage in cells with increased TERT or TERC gene dosage.
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Affiliation(s)
- Ying Cao
- Cancer Research Unit, Children's Medical Research Institute, 214 Hawkesbury Road, Westmead, NSW 2145 Australia, and University of Sydney, NSW 2006, Australia
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18
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Abstract
Telomeres are required to preserve genome integrity, chromosome stability, nuclear architecture and chromosome pairing during meiosis. Given that telomerase activity is limiting or absent in most somatic tissues, shortening of telomeres during development and aging is the rule. In vitro, telomere length operates as a mechanism to prevent uncontrolled cell growth and therefore defines the proliferation potential of a cell. In vitro, in somatic cells that have lost proliferation control, shortening of telomeres becomes the main source of genome instability leading to genetic or epigenetic changes that may allow cells to become immortal and to acquire tumor phenotypes. In vivo, mice models have indisputably shown both the protective and the promoting role of very short telomeres in cancer development. In humans, although telomere shortening and other types of telomere dysfunction probably contribute to the genome instability often detected in tumors, the specific contributions of such instability to the development of cancer remain largely undetermined.
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Freier K, Pungs S, Flechtenmacher C, Bosch FX, Lichter P, Joos S, Hofele C. Frequent high telomerase reverse transcriptase expression in primary oral squamous cell carcinoma. J Oral Pathol Med 2007; 36:267-72. [PMID: 17448136 DOI: 10.1111/j.1600-0714.2007.00531.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Gene copy number gain of chromosomal arm 5p is frequently found in oral squamous cell carcinoma (OSCC) suggesting the activation of proto-oncogenes. TERT is a candidate gene encoding for human telomerase reverse transcriptase (hTERT). The aim of the present study was to elucidate the relevance of TERT copy number gain and high hTERT expression in OSCC. METHODS Fluorescence in situ hybridization (FISH) for TERT and immunohistochemistry (IHC) for hTERT were performed to analyze TERT copy numbers and hTERT expression, respectively, on tissue microarray (TMA) sections including n = 247 OSCC and n = 105 pharyngeal and laryngeal squamous cell carcinomas (PSCC/LSCC). RESULTS Increased hTERT protein expression was more frequently found in OSCC (71.1%, 155/218) than in PSCC/LSCC (36.0%, 35/89) (P < 0.001). By contrast, specific TERT amplifications were less common in OSCC (2.1%, 4/191) compared with PSCC/LSCC (9.9%, 8/81) (P = 0.047). CONCLUSIONS High hTERT expression is a frequent finding in OSCC. It might be a promising target for the development of specific anti-neoplastic therapy approaches.
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Affiliation(s)
- Kolja Freier
- Klinik für Mund-Kiefer-Gesichtschirurgie, Universitätsklinikum Heidelberg, Heidelberg, Germany.
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20
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Lin CP, Liu JD, Chow JM, Liu CR, Liu HE. Small-molecule c-Myc inhibitor, 10058-F4, inhibits proliferation, downregulates human telomerase reverse transcriptase and enhances chemosensitivity in human hepatocellular carcinoma cells. Anticancer Drugs 2007; 18:161-70. [PMID: 17159602 DOI: 10.1097/cad.0b013e3280109424] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
c-Myc oncogene is critical for the development of hepatocellular carcinoma. Given the successful use of small-molecule inhibitors on cancers, targeting c-Myc with small-molecule inhibitors represents a promising approach. The potential of using small-molecule c-Myc inhibitor, 10058-F4, was evaluated on hepatocellular carcinoma cell lines, HepG2 and Hep3B cells. HepG2 cells were more sensitive to 10058-F4 than Hep3B cells, as demonstrated by reduced cell viability, marked morphological changes and decreased c-Myc levels. 10058-F4 arrested the cell cycle (at G0/G1 phase) and induced apoptosis upon extended treatment. These observations might be attributable to the increased cyclin-dependent kinase inhibitor, p21, and decreased cyclin D3 levels. Besides, 10058-F4 also significantly decreased the alpha-fetoprotein levels, an indicator for hepatocellular carcinoma differentiation. We further found that 10058-F4 inhibited the transactivation of human telomerase reverse transcriptase, downregulated human telomerase reverse transcriptase expression and abrogated telomerase activity. In addition, pretreatment with 10058-F4 increased the chemosensitivity of HepG2 cells to low-dose doxorubicin, 5-fluorouracil and cisplatin. Therefore, small-molecule c-Myc inhibitors might represent a novel agent, alone or in combination with conventional chemotherapeutic agents, for anti-hepatocellular carcinoma therapy.
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Affiliation(s)
- Che-Pin Lin
- Division of Hematology-Oncology, Department of Internal Medicine, Taipei City Hospital, Ren-Ai Branch, Taipei Medical University, Taipei, Taiwan
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Mabruk MJEMF, O'Flatharta C. Telomerase: is it the future diagnostic and prognostic tool in human cancer? Expert Rev Mol Diagn 2007; 5:907-16. [PMID: 16255632 DOI: 10.1586/14737159.5.6.907] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A number of methods exist to detect levels of telomerase activity and the presence of telomerase subunits in a variety of tissues. As telomerase activation seems to be an important step in tumorigenesis, accurate detection of the presence and activity of the enzyme and its subunits is vital. The original method of detecting telomerase activity was developed by Kim and coworkers in 1994, and was termed the telomeric repeat amplification protocol. This assay led to a staggering increase in the number of telomerase-associated publications in scientific journals (85 publications from 1974-1994, 5063 publications from 1994-2004). A number of methods have been described to detect telomeres and to measure their length, with the standard measurement of telomere length performed using a modification of the Southern blot protocol. RNA in situ hybridization can be performed to detect levels of the RNA component of telomerase, and standard in situ hybridization and immunohistochemistry can be applied to examine expression levels and localization of the catalytic subunit of the enzyme. Reverse transcriptase PCR has also been applied to assess expression levels of the telomerase components in various tissues. This review provides a synopsis of telomeres, telomerase, telomerase and cancer, and finally, methods for the detection of telomerase in cancer.
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Affiliation(s)
- Mohamed J E M F Mabruk
- Advanced Medical & Dental institute, University Sains Malaysia, Komplex Eureka, 11800 USM, Penang, Malaysia.
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22
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Feitelson MA, Lee J. Hepatitis B virus integration, fragile sites, and hepatocarcinogenesis. Cancer Lett 2006; 252:157-70. [PMID: 17188425 DOI: 10.1016/j.canlet.2006.11.010] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Revised: 11/08/2006] [Accepted: 11/13/2006] [Indexed: 12/31/2022]
Abstract
Chronic liver disease associated with long term hepatitis B virus (HBV) infection contributes importantly to the development of hepatocellular carcinoma (HCC). A salient feature of these chronic infections is the integration of subgenomic HBV DNA fragments into many different locations within the host DNA, suggesting that integration is random. Although this may promote genetic instability during liver regeneration which accompanies a bout of chronic liver disease, the actual role of integrated HBV DNA in hepatocarcinogenesis is uncertain. Importantly, most integration events retain the HBV open reading frame encoding the HBx antigen (HBxAg), which is the virus contribution to HCC. In addition, many integration events reported in the literature occur near or within fragile sites or other cancer associated regions of the human genome that are prone to instability in tumor development and progression. Genetic instability associated with integration potentially alters the expression of oncogenes, tumor suppressor genes, and microRNAs (miRNAs) that may contribute importantly to tumorigenesis. If so, then selected integration events may alter pathways that are rate limiting in hepatocarcinogenesis, thereby providing targets with diagnostic/prognostic potential and for therapeutic intervention.
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Affiliation(s)
- Mark A Feitelson
- Department of Pathology, Anatomy and Cell Biology, Kimmel Cancer Center, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA.
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Oh BK, Kim YJ, Park YN, Choi J, Kim KS, Park C. Quantitative assessment of hTERT mRNA expression in dysplastic nodules of HBV-related hepatocarcinogenesis. Am J Gastroenterol 2006; 101:831-8. [PMID: 16494581 DOI: 10.1111/j.1572-0241.2006.00532.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Telomerase reverse transcriptase (hTERT) is the rate-limiting determinant of telomerase, which is critical for carcinogenesis. Dysplastic nodules (DNs) appear to be preneoplastic lesions of hepatocellular carcinomas (HCCs). In this study, in order to characterize DNs, hTERT mRNA, hTERT gene dosage, and mRNA for c-myc, a transcriptional activator of hTERT were studied in human multi-step hepatocarcinogenesis. METHODS Fifty four hepatic nodules including 5 large regenerative nodules, 14 low-grade DNs, 7 high-grade DNs, 11 DNs with HCC foci and 17 HCCs, 23 livers with chronic hepatitis/cirrhosis, and 6 normal livers were examined. Transcript levels were measured by real-time quantitative RT-PCR and gene dosages by real-time PCR and Southern blotting. RESULTS The hTERT mRNA levels increased with the progression of hepatocarcinogenesis, and a significant induction in the transition between low- and high-grade DNs was seen. Most high-grade DNs strongly expressed hTERT mRNA at levels similar to those of HCCs. Twenty-one percent of low-grade DNs had high levels of hTERT mRNA, up to those of high-grade DNs and there was no difference in the pathological features between low-grade DNs with and without increased hTERT mRNA levels. No correlation was found between hTERT mRNA levels, hTERT gene dosage, and c-myc mRNA levels. CONCLUSIONS These results suggest that the induction of hTERT mRNA is an important early event and that its measurement by real-time quantitative RT-PCR is a useful tool to detect premalignant/malignant tendencies in hepatic nodules. However, hTERT gene dosage and c-myc expression are not the main mechanisms regulating hTERT expression in hepatocarcinogenesis.
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Affiliation(s)
- Bong-Kyeong Oh
- Department of Pathology, Center for Chronic Metabolic Disease Research and Yonsei Biomedical Science and Technology Initiative, Yonsei University College of Medicine, Seoul, Korea
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Abstract
Active telomerase is present in the majority of malignant human tumors, including most cases of hepatocellular carcinoma (HCC). Telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase, has been found to be expressed in HCCs, dysplastic (precancerous) nodules (DNs), and regenerative nodules arising in cirrhosis. In a study reported in this issue of the journal, hTERT mRNA levels were assessed by quantitative real-time RT-PCR in various nodular lesions dissected from liver specimens of patients with chronic hepatitis B. High levels of hTERT mRNA were present in HCCs, high-grade DNs, and occasional low-grade DNs, whereas low levels were found in normal livers, livers with chronic hepatitis B (with or without cirrhosis), large regenerative nodules, and most low-grade DNs. Therefore, quantitative assessment of hTERT mRNA may provide a useful adjunct to histopathologic evaluation of large hepatic nodules. Indeed, emerging data from gene expression analyses of DNs and HCCs suggest that hTERT can be included in sets of select genes that provide "molecular signatures" with utility in the diagnosis and management of nodular hepatic lesions. Most importantly, tackling the mechanisms of telomerase activation may provide new means of therapy for HCC and other cancers.
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