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Loe TK, Lazzerini Denchi E, Tricola GM, Azeroglu B. ALTercations at telomeres: stress, recombination and extrachromosomal affairs. Biochem Soc Trans 2023; 51:1935-1946. [PMID: 37767563 DOI: 10.1042/bst20230265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 09/29/2023]
Abstract
Approximately 15% of human cancers depend on the alternative lengthening of telomeres (ALT) pathway to maintain telomeres and proliferate. Telomeres that are elongated using ALT display unique features raising the exciting prospect of tailored cancer therapies. ALT-mediated telomere elongation shares several features with recombination-based DNA repair. Strikingly, cells that use the ALT pathway display abnormal levels of replication stress at telomeres and accumulate abundant extrachromosomal telomeric DNA. In this review, we examine recent findings that shed light on the ALT mechanisms and the strategies currently available to suppress this telomere elongation mechanism.
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Affiliation(s)
- Taylor K Loe
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, U.S.A
| | - Eros Lazzerini Denchi
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD 20892, U.S.A
| | - Gianna M Tricola
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD 20892, U.S.A
| | - Benura Azeroglu
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD 20892, U.S.A
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2
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Yang R, Han Y, Guan X, Hong Y, Meng J, Ding S, Long Q, Yi W. Regulation and clinical potential of telomerase reverse transcriptase (TERT/hTERT) in breast cancer. Cell Commun Signal 2023; 21:218. [PMID: 37612721 PMCID: PMC10463831 DOI: 10.1186/s12964-023-01244-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 07/23/2023] [Indexed: 08/25/2023] Open
Abstract
Telomerase reverse transcriptase (TERT/hTERT) serves as the pivotal catalytic subunit of telomerase, a crucial enzyme responsible for telomere maintenance and human genome stability. The high activation of hTERT, observed in over 90% of tumors, plays a significant role in tumor initiation and progression. An in-depth exploration of hTERT activation mechanisms in cancer holds promise for advancing our understanding of the disease and developing more effective treatment strategies. In breast cancer, the expression of hTERT is regulated by epigenetic, transcriptional, post-translational modification mechanisms and DNA variation. Besides its canonical function in telomere maintenance, hTERT exerts non-canonical roles that contribute to disease progression through telomerase-independent mechanisms. This comprehensive review summarizes the regulatory mechanisms governing hTERT in breast cancer and elucidates the functional implications of its activation. Given the overexpression of hTERT in most breast cancer cells, the detection of hTERT and its associated molecules are potential for enhancing early screening and prognostic evaluation of breast cancer. Although still in its early stages, therapeutic approaches targeting hTERT and its regulatory molecules show promise as viable strategies for breast cancer treatment. These methods are also discussed in this paper. Video Abstract.
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Affiliation(s)
- Ruozhu Yang
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China
| | - Yi Han
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China
| | - Xinyu Guan
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China
| | - Yue Hong
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China
| | - Jiahao Meng
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China
| | - Shirong Ding
- Department of Oncology, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China.
| | - Qian Long
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China.
| | - Wenjun Yi
- Department of General Surgery, the Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, 410011, China.
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3
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Sohn EJ, Goralsky JA, Shay JW, Min J. The Molecular Mechanisms and Therapeutic Prospects of Alternative Lengthening of Telomeres (ALT). Cancers (Basel) 2023; 15:cancers15071945. [PMID: 37046606 PMCID: PMC10093677 DOI: 10.3390/cancers15071945] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 04/14/2023] Open
Abstract
As detailed by the end replication problem, the linear ends of a cell's chromosomes, known as telomeres, shorten with each successive round of replication until a cell enters into a state of growth arrest referred to as senescence. To maintain their immortal proliferation capacity, cancer cells must employ a telomere maintenance mechanism, such as telomerase activation or the Alternative Lengthening of Telomeres pathway (ALT). With only 10-15% of cancers utilizing the ALT mechanism, progress towards understanding its molecular components and associated hallmarks has only recently been made. This review analyzes the advances towards understanding the ALT pathway by: (1) detailing the mechanisms associated with engaging the ALT pathway as well as (2) identifying potential therapeutic targets of ALT that may lead to novel cancer therapeutic treatments. Collectively, these studies indicate that the ALT molecular mechanisms involve at least two distinct pathways induced by replication stress and damage at telomeres. We suggest exploiting tumor dependency on ALT is a promising field of study because it suggests new approaches to ALT-specific therapies for cancers with poorer prognosis. While substantial progress has been made in the ALT research field, additional progress will be required to realize these advances into clinical practices to treat ALT cancers and improve patient prognoses.
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Affiliation(s)
- Eric J Sohn
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Julia A Goralsky
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA
| | - Jaewon Min
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
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4
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Kusamura S, Baratti D, De Simone M, Pasqual EM, Ansaloni L, Marrelli D, Robella M, Accarpio F, Valle M, Scaringi S, Biacchi D, Palopoli C, Gazzanelli S, Guaglio M, Deraco M. Diagnostic and Therapeutic Pathway in Diffuse Malignant Peritoneal Mesothelioma. Cancers (Basel) 2023; 15:cancers15030662. [PMID: 36765620 PMCID: PMC9913096 DOI: 10.3390/cancers15030662] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/24/2023] Open
Abstract
Diffuse malignant peritoneal mesothelioma (DMPM) is a rare form of mesothelioma that carries a very poor prognosis. The 5-year overall survival is about 20% (±5.9). Survival is optimal for patients suitable for cytoreductive surgery (CRS) with Hyperthermic Intraperitoneal Chemotherapy (HIPEC), with a median OS ranging from 34 to 92 months. However, selecting patients for surgery remains a complex task and requires a careful preoperative workup, rational analysis of prognostic profiles, and risk prediction models. Systemic chemotherapy could be offered: (1) in the adjuvant setting for high-risk patients; (2) for patients not eligible for CRS; and (3) for those with recurrent disease. It mainly includes the combination of Platin compound with Pemetrexed or immunotherapy. The biology of DMPM is still largely unknown. However, progress has been made on some fronts, such as telomere maintenance mechanisms, deregulation of apoptosis, tyrosine kinase pathways, and mutation of BRCA1-associated protein 1 (BAP1). Future perspectives should include translational research to improve our understanding of the disease biology to identify druggable targets. We should also clear the role of immune checkpoint inhibitors and investigate new locoregional technologies, such as pressurized intraperitoneal aerosol chemotherapy (PIPAC) or normothermic intraperitoneal chemotherapy (NIPEC).
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Affiliation(s)
- Shigeki Kusamura
- Peritoneal Surface Malignancies Unit, Fondazione Istituto Nazionale dei Tumori IRCCS Milano, 20133 Milan, Italy
| | - Dario Baratti
- Peritoneal Surface Malignancies Unit, Fondazione Istituto Nazionale dei Tumori IRCCS Milano, 20133 Milan, Italy
| | | | - Enrico Maria Pasqual
- AOUD Center Advanced Surgical Oncology, DAME University of Udine, 33100 Udine, Italy
| | - Luca Ansaloni
- Unit of General Surgery, San Matteo Hospital, 27100 Pavia, Italy
| | - Daniele Marrelli
- Unit of General Surgery and Surgical Oncology, Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
| | | | - Fabio Accarpio
- CRS and HIPEC Unit, Pietro Valdoni, Umberto I Policlinico di Roma, 00161 Rome, Italy
| | - Mario Valle
- Peritoneal Tumours Unit, IRCCS Regina Elena National Cancer Institute, 00144 Rome, Italy
| | | | - Daniele Biacchi
- CRS and HIPEC Unit, Pietro Valdoni, Umberto I Policlinico di Roma, 00161 Rome, Italy
| | - Carmen Palopoli
- U.O.C.—P.S.G. con O.B.I. Azienda Ospedaliera Universitaria “G. Martino”, 98125 Messina, Italy
| | - Sergio Gazzanelli
- CRS and HIPEC Unit, Pietro Valdoni, Umberto I Policlinico di Roma, 00161 Rome, Italy
| | - Marcello Guaglio
- Peritoneal Surface Malignancies Unit, Fondazione Istituto Nazionale dei Tumori IRCCS Milano, 20133 Milan, Italy
| | - Marcello Deraco
- Peritoneal Surface Malignancies Unit, Fondazione Istituto Nazionale dei Tumori IRCCS Milano, 20133 Milan, Italy
- Correspondence:
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5
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Sharaf R, Montesion M, Hopkins JF, Song J, Frampton GM, Albacker LA. A pan-cancer landscape of telomeric content shows that RAD21 and HGF alterations are associated with longer telomeres. Genome Med 2022; 14:25. [PMID: 35227290 PMCID: PMC8883689 DOI: 10.1186/s13073-022-01029-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 02/11/2022] [Indexed: 01/02/2023] Open
Abstract
Background Cancer cells can proliferate indefinitely through telomere maintenance mechanisms. These mechanisms include telomerase-dependent elongation, mediated by TERT activation, and alternative lengthening of telomeres (ALT), linked to loss of ATRX or DAXX. Methods We analyzed the telomeric content of 89,959 tumor samples within the Foundation Medicine dataset and investigated the genomic determinants of high telomeric content, linking them to clinical outcomes, when available. Results Telomeric content varied widely by disease type with leiomyosarcoma having the highest and Merkel cell carcinoma having the lowest telomeric content. In agreement with previous studies, telomeric content was significantly higher in samples with alterations in TERC, ATRX, and DAXX. We further identified that amplifications in two genes, RAD21 and HGF, were enriched in samples with high telomeric content, which was confirmed using the PCAWG/ICGC dataset. We identified the minimal amplified region associated with high telomeric content for RAD21 (8q23.1–8q24.12), which excludes MYC, and for HGF (7q21.11). Our results demonstrated that RAD21 and HGF exerted an additive telomere lengthening effect on samples with existing alterations in canonical genes previously associated with telomere elongation. Furthermore, patients with breast cancer who harbor RAD21 alterations had poor median overall survival and trended towards higher levels of Ki-67 staining. Conclusions This study highlights the importance of the role played by RAD21 (8q23.1–8q24.12) and HGF (7q21.11) in the lengthening of telomeres, supporting unlimited replication in tumors. These findings open avenues for work aimed at targeting this crucial pathway in tumorigenesis. Supplementary Information The online version contains supplementary material available at 10.1186/s13073-022-01029-7.
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Affiliation(s)
- Radwa Sharaf
- Foundation Medicine Inc, 150 Second Street, Cambridge, MA, 02141, USA
| | - Meagan Montesion
- Foundation Medicine Inc, 150 Second Street, Cambridge, MA, 02141, USA
| | - Julia F Hopkins
- Foundation Medicine Inc, 150 Second Street, Cambridge, MA, 02141, USA
| | - Jiarong Song
- Foundation Medicine Inc, 150 Second Street, Cambridge, MA, 02141, USA
| | | | - Lee A Albacker
- Foundation Medicine Inc, 150 Second Street, Cambridge, MA, 02141, USA.
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Sung JY, Cheong JH. Pan-Cancer Analysis of Clinical Relevance via Telomere Maintenance Mechanism. Int J Mol Sci 2021; 22:ijms222011101. [PMID: 34681758 PMCID: PMC8538844 DOI: 10.3390/ijms222011101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/04/2021] [Accepted: 10/13/2021] [Indexed: 12/24/2022] Open
Abstract
Understanding the telomere maintenance mechanism (TMM) in immortal cancer cells is vital for TMM-targeted therapies in clinical settings. In this study, we classified four telomere maintenance mechanisms into telomerase, ALT, telomerase + ALT, and non-defined telomere maintenance mechanism (NDTMM) across 31 cancer types using 10,704 transcriptomic datasets from The Cancer Genome Atlas. Our results demonstrated that approximately 50% of the total cohort displayed ALT activity with high telomerase activity in most cancer types. We confirmed significant patient prognoses according to distinct TMMs in six cancer types: adrenocortical carcinoma (ACC), PAAD, HNSC, SARC, GBM, and metastatic cancer. Patients with metastasis had a poor prognosis in the ALT group (p < 0.006) subjected to RAS protein signal transduction. Glioblastoma patients had poor prognosis in NDTMM (p < 0.0043) and showed high levels of myeloid leukocyte activation. Pancreatic adenocarcinoma (p < 0.04) and head and neck squamous cell carcinoma (p < 0.046) patients had a good prognosis in the ALT group with high immune cell activation. Furthermore, we showed that master transcriptional regulators might affect the selection of the TMM pathway and explained why different telomere maintenance mechanisms exist. Furthermore, they can be used to segregate patients and predict responders to different TMM-targeted therapeutics.
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Affiliation(s)
- Ji-Yong Sung
- Department of Biomedical Systems Informatics, Yonsei University College of Medicine, Seoul 03722, Korea;
- Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Jae-Ho Cheong
- Department of Biomedical Systems Informatics, Yonsei University College of Medicine, Seoul 03722, Korea;
- Department of Surgery, Yonsei University College of Medicine, Seoul 03722, Korea
- Yonsei Biomedical Research Institute, Yonsei University College of Medicine, Seoul 03722, Korea
- Department of Biochemistry & Molecular Biology, Yonsei University College of Medicine, Seoul 03722, Korea
- Department of Research & Development, VeraVerse Inc., Seoul 03722, Korea
- Correspondence:
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7
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Nersisyan L, Simonyan A, Binder H, Arakelyan A. Telomere Maintenance Pathway Activity Analysis Enables Tissue- and Gene-Level Inferences. Front Genet 2021; 12:662464. [PMID: 33897770 PMCID: PMC8058386 DOI: 10.3389/fgene.2021.662464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/16/2021] [Indexed: 12/31/2022] Open
Abstract
Telomere maintenance is one of the mechanisms ensuring indefinite divisions of cancer and stem cells. Good understanding of telomere maintenance mechanisms (TMM) is important for studying cancers and designing therapies. However, molecular factors triggering selective activation of either the telomerase dependent (TEL) or the alternative lengthening of telomeres (ALT) pathway are poorly understood. In addition, more accurate and easy-to-use methodologies are required for TMM phenotyping. In this study, we have performed literature based reconstruction of signaling pathways for the ALT and TEL TMMs. Gene expression data were used for computational assessment of TMM pathway activities and compared with experimental assays for TEL and ALT. Explicit consideration of pathway topology makes bioinformatics analysis more informative compared to computational methods based on simple summary measures of gene expression. Application to healthy human tissues showed high ALT and TEL pathway activities in testis, and identified genes and pathways that may trigger TMM activation. Our approach offers a novel option for systematic investigation of TMM activation patterns across cancers and healthy tissues for dissecting pathway-based molecular markers with diagnostic impact.
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Affiliation(s)
- Lilit Nersisyan
- Bioinformatics Group, Institute of Molecular Biology, National Academy of Sciences, Yerevan, Armenia.,Pathverse, Yerevan, Armenia
| | - Arman Simonyan
- Bioinformatics Group, Institute of Molecular Biology, National Academy of Sciences, Yerevan, Armenia
| | - Hans Binder
- Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany
| | - Arsen Arakelyan
- Bioinformatics Group, Institute of Molecular Biology, National Academy of Sciences, Yerevan, Armenia.,Pathverse, Yerevan, Armenia
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8
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da Silva GG, Morais KS, Arcanjo DS, de Oliveira DM. Clinical Relevance of Alternative Lengthening of Telomeres in Cancer. Curr Top Med Chem 2020; 20:485-497. [PMID: 31924155 DOI: 10.2174/1568026620666200110112854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 12/11/2019] [Accepted: 12/16/2019] [Indexed: 11/22/2022]
Abstract
The alternative lengthening of telomere (ALT) is a pathway responsible for cell immortalization in some kinds of tumors. Since the first description of ALT is relatively recent in the oncology field, its mechanism remains elusive, but recent works address ALT-related proteins or cellular structures as potential druggable targets for more specific and efficient antitumor therapies. Moreover, some new generation compounds for antitelomerase therapy in cancer were able to provoke acquisition of ALT phenotype in treated tumors, enhancing the importance of studies on this alternative lengthening of the telomere. However, ALT has been implicated in different - sometimes opposite - outcomes, according to the tumor type studied. Then, in order to design and develop new drugs for ALT+ cancer in an effective way, it is crucial to understand its clinical implications. In this review, we gathered works published in the last two decades to highlight the clinical relevance of ALT on oncology.
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Affiliation(s)
- Guilherme G da Silva
- Department of Biological Basis of Health Sciences, University of Brasilia, Ceilandia Campus, Federal District, Brazil
| | - Karollyne S Morais
- Laboratory of Molecular Pathology of Cancer, University of Brasilia, Federal District, Brazil
| | - Daniel S Arcanjo
- Department of Biological Basis of Health Sciences, University of Brasilia, Ceilandia Campus, Federal District, Brazil
| | - Diêgo M de Oliveira
- Department of Biological Basis of Health Sciences, University of Brasilia, Ceilandia Campus, Federal District, Brazil.,Laboratory of Molecular Pathology of Cancer, University of Brasilia, Federal District, Brazil
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9
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Rangel-Pozzo A, Sisdelli L, Cordioli MIV, Vaisman F, Caria P, Mai S, Cerutti JM. Genetic Landscape of Papillary Thyroid Carcinoma and Nuclear Architecture: An Overview Comparing Pediatric and Adult Populations. Cancers (Basel) 2020; 12:E3146. [PMID: 33120984 PMCID: PMC7693829 DOI: 10.3390/cancers12113146] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/15/2020] [Accepted: 10/26/2020] [Indexed: 12/16/2022] Open
Abstract
Thyroid cancer is a rare malignancy in the pediatric population that is highly associated with disease aggressiveness and advanced disease stages when compared to adult population. The biological and molecular features underlying pediatric and adult thyroid cancer pathogenesis could be responsible for differences in the clinical presentation and prognosis. Despite this, the clinical assessment and treatments used in pediatric thyroid cancer are the same as those implemented for adults and specific personalized target treatments are not used in clinical practice. In this review, we focus on papillary thyroid carcinoma (PTC), which represents 80-90% of all differentiated thyroid carcinomas. PTC has a high rate of gene fusions and mutations, which can influence the histologic subtypes in both children and adults. This review also highlights telomere-related genomic instability and changes in nuclear organization as novel biomarkers for thyroid cancers.
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Affiliation(s)
- Aline Rangel-Pozzo
- Cell Biology, Research Institute of Oncology and Hematology, University of Manitoba, CancerCare Manitoba, Winnipeg, MB R3E 0V9, Canada;
| | - Luiza Sisdelli
- Genetic Bases of Thyroid Tumors Laboratory, Division of Genetics, Department of Morphology and Genetics, Universidade Federal de São Paulo/EPM, São Paulo, SP 04039-032, Brazil; (L.S.); (M.I.V.C.); (J.M.C.)
| | - Maria Isabel V. Cordioli
- Genetic Bases of Thyroid Tumors Laboratory, Division of Genetics, Department of Morphology and Genetics, Universidade Federal de São Paulo/EPM, São Paulo, SP 04039-032, Brazil; (L.S.); (M.I.V.C.); (J.M.C.)
| | - Fernanda Vaisman
- Instituto Nacional do Câncer, Rio de Janeiro, RJ 22451-000, Brazil;
| | - Paola Caria
- Department of Biomedical Sciences, University of Cagliari, 09042 Cagliari, Italy
| | - Sabine Mai
- Cell Biology, Research Institute of Oncology and Hematology, University of Manitoba, CancerCare Manitoba, Winnipeg, MB R3E 0V9, Canada;
| | - Janete M. Cerutti
- Genetic Bases of Thyroid Tumors Laboratory, Division of Genetics, Department of Morphology and Genetics, Universidade Federal de São Paulo/EPM, São Paulo, SP 04039-032, Brazil; (L.S.); (M.I.V.C.); (J.M.C.)
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10
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The Role of Alternative Lengthening of Telomeres Mechanism in Cancer: Translational and Therapeutic Implications. Cancers (Basel) 2020; 12:cancers12040949. [PMID: 32290440 PMCID: PMC7226354 DOI: 10.3390/cancers12040949] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/09/2020] [Accepted: 04/10/2020] [Indexed: 12/17/2022] Open
Abstract
Telomere maintenance mechanisms (i.e., telomerase activity (TA) and the alternative lengthening of telomere (ALT) mechanism) contribute to tumorigenesis by providing unlimited proliferative capacity to cancer cells. Although the role of either telomere maintenance mechanisms seems to be equivalent in providing a limitless proliferative ability to tumor cells, the contribution of TA and ALT to the clinical outcome of patients may differ prominently. In addition, several strategies have been developed to interfere with TA in cancer, including Imetelstat that has been the first telomerase inhibitor tested in clinical trials. Conversely, the limited information available on the molecular underpinnings of ALT has hindered thus far the development of genuine ALT-targeting agents. Moreover, whether anti-telomerase therapies may be hampered or not by possible adaptive responses is still debatable. Nonetheless, it is plausible hypothesizing that treatment with telomerase inhibitors may exert selective pressure for the emergence of cancer cells that become resistant to treatment by activating the ALT mechanism. This notion, together with the evidence that both telomere maintenance mechanisms may coexist within the same tumor and may distinctly impinge on patients' outcomes, suggests that ALT may exert an unexpected role in tumor biology that still needs to be fully elucidated.
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11
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Claude E, Decottignies A. Telomere maintenance mechanisms in cancer: telomerase, ALT or lack thereof. Curr Opin Genet Dev 2020; 60:1-8. [PMID: 32114293 DOI: 10.1016/j.gde.2020.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/10/2020] [Accepted: 01/17/2020] [Indexed: 12/31/2022]
Abstract
Cancer cells acquire replicative immortality by activating a telomere maintenance mechanism (TMM), either the telomerase or the Alternative Lengthening of Telomeres (ALT) mechanism. ALT is frequently activated in tumors derived from mesenchymal cells, which are more frequent in childhood cancers. Recent studies showed that, occasionally, cancer cells can arise without any TMM activation. Here, we discuss the challenge in assessing which TMM is activated in tumors. We also evaluate the prevalence of ALT mechanism in pediatric cancers and review the associated survival prognosis in different tumor types. Finally, we discuss about possible anti-TMM therapies for new emerging cancer treatments.
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12
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M'kacher R, Cuceu C, Al Jawhari M, Morat L, Frenzel M, Shim G, Lenain A, Hempel WM, Junker S, Girinsky T, Colicchio B, Dieterlen A, Heidingsfelder L, Borie C, Oudrhiri N, Bennaceur-Griscelli A, Moralès O, Renaud S, Van de Wyngaert Z, Jeandidier E, Delhem N, Carde P. The Transition between Telomerase and ALT Mechanisms in Hodgkin Lymphoma and Its Predictive Value in Clinical Outcomes. Cancers (Basel) 2018; 10:E169. [PMID: 29848986 PMCID: PMC6025489 DOI: 10.3390/cancers10060169] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/18/2018] [Accepted: 05/25/2018] [Indexed: 11/16/2022] Open
Abstract
Background: We analyzed telomere maintenance mechanisms (TMMs) in lymph node samples from HL patients treated with standard therapy. The TMMs correlated with clinical outcomes of patients. Materials and Methods: Lymph node biopsies obtained from 38 HL patients and 24 patients with lymphadenitis were included in this study. Seven HL cell lines were used as in vitro models. Telomerase activity (TA) was assessed by TRAP assay and verified through hTERT immunofluorescence expression; alternative telomere lengthening (ALT) was also assessed, along with EBV status. Results: Both TA and ALT mechanisms were present in HL lymph nodes. Our findings were reproduced in HL cell lines. The highest levels of TA were expressed in CD30-/CD15- cells. Small cells were identified with ALT and TA. Hodgkin and Reed Sternberg cells contained high levels of PML bodies, but had very low hTERT expression. There was a significant correlation between overall survival (p < 10-3), event-free survival (p < 10-4), and freedom from progression (p < 10-3) and the presence of an ALT profile in lymph nodes of EBV+ patients. Conclusion: The presence of both types of TMMs in HL lymph nodes and in HL cell lines has not previously been reported. TMMs correlate with the treatment outcome of EBV+ HL patients.
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Affiliation(s)
- Radhia M'kacher
- Laboratoire de Radiobiologie et d'Oncologie, IRCM/DSV/CEA, 92265 Fontenay aux Roses, France.
- Cell Environment, DNA Damages R&D, Oncology Section, 75020 Paris, France.
| | - Corina Cuceu
- Laboratoire de Radiobiologie et d'Oncologie, IRCM/DSV/CEA, 92265 Fontenay aux Roses, France.
| | - Mustafa Al Jawhari
- Laboratoire de Radiobiologie et d'Oncologie, IRCM/DSV/CEA, 92265 Fontenay aux Roses, France.
| | - Luc Morat
- Laboratoire de Radiobiologie et d'Oncologie, IRCM/DSV/CEA, 92265 Fontenay aux Roses, France.
| | - Monika Frenzel
- Laboratoire de Radiobiologie et d'Oncologie, IRCM/DSV/CEA, 92265 Fontenay aux Roses, France.
| | - Grace Shim
- Laboratoire de Radiobiologie et d'Oncologie, IRCM/DSV/CEA, 92265 Fontenay aux Roses, France.
| | - Aude Lenain
- Laboratoire de Radiobiologie et d'Oncologie, IRCM/DSV/CEA, 92265 Fontenay aux Roses, France.
| | - William M Hempel
- Laboratoire de Radiobiologie et d'Oncologie, IRCM/DSV/CEA, 92265 Fontenay aux Roses, France.
| | - Steffen Junker
- Institute of Biomedicine, University of Aarhus, DK-8000 Aarhus C, Denmark.
| | - Theodore Girinsky
- Department of Radiation Therapy, Gustave Roussy Cancer Campus, 94808 Villejuif, France.
| | - Bruno Colicchio
- IRIMAS, Institut de Recherche en Informatique, Mathématiques, Automatique et Signal, Université de Haute-Alsace, 68093 Mulhouse, France.
| | - Alain Dieterlen
- IRIMAS, Institut de Recherche en Informatique, Mathématiques, Automatique et Signal, Université de Haute-Alsace, 68093 Mulhouse, France.
| | | | - Claire Borie
- Université Paris Sud, Service d'hématologie moléculaire et cytogénétique Paul brousse CHU paris Sud, Inserm UMRS935, 94800 Villejuif, France.
| | - Noufissa Oudrhiri
- Université Paris Sud, Service d'hématologie moléculaire et cytogénétique Paul brousse CHU paris Sud, Inserm UMRS935, 94800 Villejuif, France.
| | - Annelise Bennaceur-Griscelli
- Université Paris Sud, Service d'hématologie moléculaire et cytogénétique Paul brousse CHU paris Sud, Inserm UMRS935, 94800 Villejuif, France.
| | - Olivier Moralès
- CNRS, Institut Pasteur de Lille, UMR 8161-Immunoregulation of Virus-induced Cancers Team, F-59000 Lille, France.
| | - Sarah Renaud
- CNRS, Institut Pasteur de Lille, UMR 8161-Immunoregulation of Virus-induced Cancers Team, F-59000 Lille, France.
| | - Zoé Van de Wyngaert
- CHRU Lille Service des Maladies du Sang, Hopital Huriez, 59000 Lille, France.
| | - Eric Jeandidier
- Service de génétique, Groupe hospitalier de la région de Mulhouse Sud-Alsace, 68093 Mulhouse, France.
| | - Nadira Delhem
- CNRS, Institut Pasteur de Lille, UMR 8161-Immunoregulation of Virus-induced Cancers Team, F-59000 Lille, France.
| | - Patrice Carde
- Department of Medicine, Gustave Roussy Cancer Campus, 94808 Villejuif, France.
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13
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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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14
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De Vitis M, Berardinelli F, Sgura A. Telomere Length Maintenance in Cancer: At the Crossroad between Telomerase and Alternative Lengthening of Telomeres (ALT). Int J Mol Sci 2018; 19:ijms19020606. [PMID: 29463031 PMCID: PMC5855828 DOI: 10.3390/ijms19020606] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 02/12/2018] [Accepted: 02/14/2018] [Indexed: 02/07/2023] Open
Abstract
Eukaryotic cells undergo continuous telomere shortening as a consequence of multiple rounds of replications. During tumorigenesis, cells have to acquire telomere DNA maintenance mechanisms (TMMs) in order to counteract telomere shortening, to preserve telomeres from DNA damage repair systems and to avoid telomere-mediated senescence and/or apoptosis. For this reason, telomere maintenance is an essential step in cancer progression. Most human tumors maintain their telomeres expressing telomerase, whereas a lower but significant proportion activates the alternative lengthening of telomeres (ALT) pathway. However, evidence about the coexistence of ALT and telomerase has been found both in vivo in the same cancer populations and in vitro in engineered cellular models, making the distinction between telomerase- and ALT-positive tumors elusive. Indeed, after the development of drugs able to target telomerase, the capability for some cancer cells to escape death, switching from telomerase to ALT, was highlighted. Unfortunately, to date, the mechanism underlying the possible switching or the coexistence of telomerase and ALT within the same cell or populations is not completely understood and different factors could be involved. In recent years, different studies have tried to shed light on the complex regulation network that controls the transition between the two TMMs, suggesting a role for embryonic cancer origin, epigenetic modifications, and specific genes activation—both in vivo and in vitro. In this review, we examine recent findings about the cancer-associated differential activation of the two known TMMs and the possible factors implicated in this process. Furthermore, some studies on cancers are also described that did not display any TMM.
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Affiliation(s)
- Marco De Vitis
- Department of Science, Roma Tre University, 00146 Rome, Italy.
| | | | - Antonella Sgura
- Department of Science, Roma Tre University, 00146 Rome, Italy.
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15
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Cimino-Reale G, Gandellini P, Santambrogio F, Recagni M, Zaffaroni N, Folini M. miR-380-5p-mediated repression of TEP1 and TSPYL5 interferes with telomerase activity and favours the emergence of an "ALT-like" phenotype in diffuse malignant peritoneal mesothelioma cells. J Hematol Oncol 2017; 10:140. [PMID: 28716051 PMCID: PMC5513108 DOI: 10.1186/s13045-017-0510-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/10/2017] [Indexed: 02/06/2023] Open
Abstract
Background Understanding the molecular/cellular underpinnings of diffuse malignant peritoneal mesothelioma (DMPM), a fatal malignancy with limited therapeutic options, is of utmost importance for the fruitful management of the disease. In this context, we previously found that telomerase activity (TA), which accounts for the limitless proliferative potential of cancer cells, is prognostic for disease relapse and cancer-related death in DMPM patients. Consequently, the identification of factors involved in telomerase activation/regulation may pave the way towards the development of novel therapeutic interventions for the disease. Here, the capability of miR-380-5p, a microRNA negligibly expressed in telomerase-positive DMPM clinical specimens, to interfere with telomerase-mediated telomere maintenance and, hence, with cancer cell growth was assessed on preclinical models of DMPM. Methods DMPM cells were transfected with a miR-380-5p synthetic precursor, and the effects of miRNA replacement were evaluated in terms of growing capability, induction of apoptosis and interference with TA. Reiterated weekly transfections were also performed in order to analyse the phenotype arising upon prolonged miR-380-5p reconstitution in DMPM cells. Results The ectopic expression of miR-380-5p elicited a remarkable inhibition of TA and resulted in DMPM cell growth impairment and apoptosis induction. In particular, we demonstrated for the first time that these effects were the result of a molecular circuitry converging on telomerase associated protein 1 (TEP1), where the miRNA was able to target the gene both directly in unconventional targeting modality and indirectly via p53 accumulation consequent to miRNA-mediated downregulation of testis-specific protein, Y-encoded-like 5 gene. Moreover, miR-380-5p did not cause telomere attrition and cell growth arrest in long-term DMPM transfectants, which in turn showed slightly elongated telomeres and molecular features (e.g. c-circle DNA and reduced expression levels of chromatin remodeler ATRX) resembling an alternative lengthening of telomeres (ALT) phenotype. Conclusions miR-380-5p interferes with TA in DMPM cells by targeting TEP1. Notably, in the long-term setting, miR-380-5p-mediated impairment of TA did not result in telomere attrition. Instead, a phenotype reminiscent of ALT emerged in DMPM cells as possible compensatory pathway that safeguards DMPM cell growth, an event that may be regarded as a potential resistance mechanism to anticancer therapies based on telomerase inhibitors. Electronic supplementary material The online version of this article (doi:10.1186/s13045-017-0510-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Graziella Cimino-Reale
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Amadeo, 42 - 20133, Milano, Italy
| | - Paolo Gandellini
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Amadeo, 42 - 20133, Milano, Italy
| | - Francesca Santambrogio
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Amadeo, 42 - 20133, Milano, Italy
| | - Marta Recagni
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Amadeo, 42 - 20133, Milano, Italy
| | - Nadia Zaffaroni
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Amadeo, 42 - 20133, Milano, Italy
| | - Marco Folini
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Amadeo, 42 - 20133, Milano, Italy.
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16
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Abstract
Bacteria and viruses possess circular DNA, whereas eukaryotes with typically very large DNA molecules have had to evolve into linear chromosomes to circumvent the problem of supercoiling circular DNA of that size. Consequently, such organisms possess telomeres to cap chromosome ends. Telomeres are essentially tandem repeats of any DNA sequence that are present at the ends of chromosomes. Their biology has been an enigmatic one, involving various molecules interacting dynamically in an evolutionarily well-trimmed fashion. Telomeres range from canonical hexameric repeats in most eukaryotes to unimaginably random retrotransposons, which attach to chromosome ends and reverse-transcribe to DNA in some plants and insects. Telomeres invariably associate with specialised protein complexes that envelop it, also regulating access of the ends to legitimate enzymes involved in telomere metabolism. They also transcribe into repetitive RNA which also seems to be playing significant roles in telomere maintenance. Telomeres thus form the intersection of DNA, protein, and RNA molecules acting in concert to maintain chromosome integrity. Telomere biology is emerging to appear ever more complex than previously envisaged, with the continual discovery of more molecules and interplays at the telomeres. This review also includes a section dedicated to the history of telomere biology, and intends to target the scientific audience new to the field by rendering an understanding of the phenomenon of chromosome end protection at large, with more emphasis on the biology of human telomeres. The review provides an update on the field and mentions the questions that need to be addressed.
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Affiliation(s)
- Shriram Venkatesan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore, Singapore.
| | - Aik Kia Khaw
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore, Singapore.
- Clinical Research Unit, Khoo Teck Puat Hospital, 768828 Singapore, Singapore.
| | - Manoor Prakash Hande
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore, Singapore.
- Tembusu College, National University of Singapore, 138598 Singapore, Singapore.
- VIT University, Vellore 632014, India.
- Mangalore University, Mangalore 574199, India.
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17
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Robinson NJ, Schiemann WP. Means to the ends: The role of telomeres and telomere processing machinery in metastasis. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1866:320-329. [PMID: 27768860 PMCID: PMC5138103 DOI: 10.1016/j.bbcan.2016.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/12/2016] [Accepted: 10/15/2016] [Indexed: 12/29/2022]
Abstract
Despite significant clinical advancements, cancer remains a leading cause of mortality throughout the world due largely to the process of metastasis and the dissemination of cancer cells from their primary tumor of origin to distant secondary sites. The clinical burden imposed by metastasis is further compounded by a paucity of information regarding the factors that mediate metastatic progression. Linear chromosomes are capped by structures known as telomeres, which dictate cellular lifespan in humans by shortening progressively during successive cell divisions. Although telomere shortening occurs in nearly all somatic cells, telomeres may be elongated via two seemingly disjoint pathways: (i) telomerase-mediated extension, and (ii) homologous recombination-based alternative lengthening of telomeres (ALT). Both telomerase and ALT are activated in various human cancers, with more recent evidence implicating both pathways as potential mediators of metastasis. Here we review the known roles of telomere homeostasis in metastasis and posit a mechanism whereby metastatic activity is determined by a dynamic fluctuation between ALT and telomerase, as opposed to the mere activation of a generic telomere elongation program. Additionally, the pleiotropic nature of the telomere processing machinery makes it an attractive therapeutic target for metastasis, and as such, we also explore the therapeutic implications of our proposed mechanism.
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Affiliation(s)
- Nathaniel J Robinson
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - William P Schiemann
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA.
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18
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Apte MS, Cooper JP. Life and cancer without telomerase: ALT and other strategies for making sure ends (don't) meet. Crit Rev Biochem Mol Biol 2016; 52:57-73. [PMID: 27892716 DOI: 10.1080/10409238.2016.1260090] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
While most cancer cells rely on telomerase expression/re-activation for linear chromosome maintenance and sustained proliferation, a significant population of cancers (10-15%) employs telomerase-independent strategies, collectively dubbed Alternative Lengthening of Telomeres (ALT). Most ALT cells relax the usual role of telomeres as inhibitors of local homologous recombination while maintaining the ability of telomeres to prohibit local non-homologous end joining reactions. Here we review current concepts surrounding how ALT telomeres achieve this new balance via alterations in chromatin landscape, DNA damage repair processes and handling of telomeric transcription. We also discuss telomerase independent end maintenance strategies utilized by other organisms, including fruitflies and yeasts, to draw parallels and contrasts and highlight additional modes, beyond ALT, that may be available to telomerase-minus cancers. We conclude by commenting on promises and challenges in the development of effective anti-ALT cancer therapies.
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Affiliation(s)
- Manasi S Apte
- a Laboratory of Biochemistry and Molecular Biology , Center for Cancer Research, National Cancer Institute, NIH , Bethesda , MD , USA
| | - Julia Promisel Cooper
- a Laboratory of Biochemistry and Molecular Biology , Center for Cancer Research, National Cancer Institute, NIH , Bethesda , MD , USA
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19
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Amorim JP, Santos G, Vinagre J, Soares P. The Role of ATRX in the Alternative Lengthening of Telomeres (ALT) Phenotype. Genes (Basel) 2016; 7:E66. [PMID: 27657132 PMCID: PMC5042396 DOI: 10.3390/genes7090066] [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: 06/22/2016] [Revised: 09/07/2016] [Accepted: 09/12/2016] [Indexed: 12/15/2022] Open
Abstract
Telomeres are responsible for protecting chromosome ends in order to prevent the loss of coding DNA. Their maintenance is required for achieving immortality by neoplastic cells and can occur by upregulation of the telomerase enzyme or through a homologous recombination-associated process, the alternative lengthening of telomeres (ALT). The precise mechanisms that govern the activation of ALT or telomerase in tumor cells are not fully understood, although cellular origin may favor one of the other mechanisms that have been found thus far in mutual exclusivity. Specific mutational events influence ALT activation and maintenance: a unifying frequent feature of tumors that acquire this phenotype are the recurrent mutations of the Alpha Thalassemia/Mental Retardation Syndrome X-Linked (ATRX) or Death-Domain Associated Protein (DAXX) genes. This review summarizes the established criteria about this phenotype: its prevalence, theoretical molecular mechanisms and relation with ATRX, DAXX and other proteins (directly or indirectly interacting and resulting in the ALT phenotype).
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Affiliation(s)
- João P Amorim
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto 4200-135, Portugal.
- Instituto de Patologia e Imunologia Molecular da Universidade do Porto (Ipatimup), Porto 4200-135, Portugal.
- Instituto de Ciências Biomédicas Abel Salazar da Universidade do Porto, Porto 4050-313, Portugal.
| | - Gustavo Santos
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto 4200-135, Portugal.
- Instituto de Patologia e Imunologia Molecular da Universidade do Porto (Ipatimup), Porto 4200-135, Portugal.
- Instituto de Ciências Biomédicas Abel Salazar da Universidade do Porto, Porto 4050-313, Portugal.
| | - João Vinagre
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto 4200-135, Portugal.
- Instituto de Patologia e Imunologia Molecular da Universidade do Porto (Ipatimup), Porto 4200-135, Portugal.
- Instituto de Ciências Biomédicas Abel Salazar da Universidade do Porto, Porto 4050-313, Portugal.
| | - Paula Soares
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto 4200-135, Portugal.
- Instituto de Patologia e Imunologia Molecular da Universidade do Porto (Ipatimup), Porto 4200-135, Portugal.
- Instituto de Ciências Biomédicas Abel Salazar da Universidade do Porto, Porto 4050-313, Portugal.
- Departamento de Patologia e Oncologia, Faculdade de Medicina da Universidade do Porto, Porto 4200-139, Portugal.
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20
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Hu Y, Shi G, Zhang L, Li F, Jiang Y, Jiang S, Ma W, Zhao Y, Songyang Z, Huang J. Switch telomerase to ALT mechanism by inducing telomeric DNA damages and dysfunction of ATRX and DAXX. Sci Rep 2016; 6:32280. [PMID: 27578458 PMCID: PMC5006076 DOI: 10.1038/srep32280] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 08/04/2016] [Indexed: 12/12/2022] Open
Abstract
Activation of telomerase or alternative lengthening of telomeres (ALT) is necessary for tumours to escape from dysfunctional telomere-mediated senescence. Anti-telomerase drugs might be effective in suppressing tumour growth in approximately 85–90% of telomerase-positive cancer cells. However, there are still chances for these cells to bypass drug treatment after switching to the ALT mechanism to maintain their telomere integrity. But the mechanism underlying this switch is unknown. In this study, we used telomerase-positive cancer cells (HTC75) to discover the mechanism of the telomerase-ALT switch by inducing telomere-specific DNA damage, alpha-thalassemia X-linked syndrome protein (ATRX) knockdown and deletion of death associated protein (DAXX). Surprisingly, two important ALT hallmarks in the ALT-like HTC75 cells were observed after treatments: ALT-associated promyelocytic leukaemia bodies (APBs) and extrachromosomal circular DNA of telomeric repeats. Moreover, knocking out hTERT by utilizing the CRISPR/Cas9 technique led to telomere elongation in a telomerase-independent manner in ALT-like HTC75 cells. In summary, this is the first report to show that inducing telomeric DNA damage, disrupting the ATRX/DAXX complex and inhibiting telomerase activity in telomerase-positive cancer cells lead to the ALT switch.
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Affiliation(s)
- Yang Hu
- Key Laboratory of Gene Engineering of the Ministry of Education and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.,Key Laboratory of Reproductive Medicine of Guangdong Province, School of Life Sciences and the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510275, China
| | - Guang Shi
- Key Laboratory of Gene Engineering of the Ministry of Education and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.,Key Laboratory of Reproductive Medicine of Guangdong Province, School of Life Sciences and the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510275, China
| | - Laichen Zhang
- Key Laboratory of Gene Engineering of the Ministry of Education and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Feng Li
- Key Laboratory of Gene Engineering of the Ministry of Education and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Yuanling Jiang
- Key Laboratory of Gene Engineering of the Ministry of Education and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Shuai Jiang
- Key Laboratory of Gene Engineering of the Ministry of Education and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Wenbin Ma
- Key Laboratory of Gene Engineering of the Ministry of Education and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Yong Zhao
- Key Laboratory of Gene Engineering of the Ministry of Education and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Zhou Songyang
- Key Laboratory of Gene Engineering of the Ministry of Education and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.,Key Laboratory of Reproductive Medicine of Guangdong Province, School of Life Sciences and the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510275, China
| | - Junjiu Huang
- Key Laboratory of Gene Engineering of the Ministry of Education and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.,Key Laboratory of Reproductive Medicine of Guangdong Province, School of Life Sciences and the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510275, China
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21
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Abstract
Activation of a telomere maintenance mechanism (TMM) is permissive for replicative immortality and a hallmark of human cancer. While most cancers rely on reactivation of telomerase, a significant fraction utilizes the recombination dependent alternative lengthening of telomeres (ALT) pathway. ALT is enriched in tumors of mesenchymal origin, including those arising from bone, soft tissue, and the nervous system, and usually portends a poor prognosis. Recent insights into the mechanisms of ALT are uncovering novel avenues to exploit vulnerabilities and may facilitate clinical development of ALT detection assays and personalized treatment decisions based on TMM status. Treatments targeting ALT may hold promise for a broadly applicable therapeutic modality specific to mesenchymal lineage tumors, something that has thus far remained elusive.
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Affiliation(s)
- Robert L Dilley
- Departments of Cancer Biology and Pathology, Abramson Family Cancer Research Institute, Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
| | - Roger A Greenberg
- Departments of Cancer Biology and Pathology, Abramson Family Cancer Research Institute, Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
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22
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23
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Reddel RR. Telomere maintenance mechanisms in cancer: clinical implications. Curr Pharm Des 2015; 20:6361-74. [PMID: 24975603 PMCID: PMC4262939 DOI: 10.2174/1381612820666140630101047] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 06/26/2014] [Indexed: 01/20/2023]
Abstract
The presence of immortal cell populations with an up-regulated telomere maintenance mechanism (TMM) is an almost universal characteristic of cancers, whereas normal somatic cells are unable to prevent proliferation-associated telomere shortening and have a limited proliferative potential. TMMs and related aspects of telomere structure and function therefore appear to be ideal targets for the development of anticancer therapeutics. Such treatments would be targeted to a specific cancer-related molecular abnormality, and also be broad-spectrum in that they would be expected to be potentially applicable to most cancers. However, the telomere biology of normal and malignant human cells is a relatively young research field with large numbers of unanswered questions, so the optimal design of TMM-targeted therapeutic approaches remains unclear. This review outlines the opportunities and challenges presented by telomeres and TMMs for clinical management of cancer.
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Affiliation(s)
- Roger R Reddel
- Children's Medical Research Institute, 214 Hawkesbury Road, Westmead, New South Wales 2145, Australia.
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24
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Deraco M, Cabras A, Baratti D, Kusamura S. Immunohistochemical Evaluation of Minichromosome Maintenance Protein 7 (MCM7), Topoisomerase IIα, and Ki-67 in Diffuse Malignant Peritoneal Mesothelioma Patients Using Tissue Microarray. Ann Surg Oncol 2015; 22:4344-51. [PMID: 25777091 DOI: 10.1245/s10434-015-4498-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Indexed: 12/18/2022]
Abstract
PURPOSE Immunohistochemistry and tissue microarray (TMA) were used to perform a prognostic analysis of markers related to cell proliferation in diffuse malignant peritoneal mesothelioma (DMPM). METHODS Clinicopathologic data were extracted from a prospectively collected database containing cases of peritoneal mesothelioma treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in the National Cancer Institute of Milan from 1995 to 2013. Eighty-one DMPM patients were recruited and their tissue samples were used to construct TMAs. We evaluated the immunoexpressions of markers related to cell proliferation-topoisomerase IIα, minichromosome maintenance protein 7 (MCM7), and Ki-67-and then conducted a multivariate Cox model to identify the predictors of overall survival (OS) and progression-free survival (PFS) among the following parameters: age, sex, Eastern Cooperative Oncology Group (ECOG) performance status, baseline serum albumin, Charlson Comorbidity Index, previous systemic chemotherapy, histological subtype (epithelioid vs. biphasic/sarcomatoid), peritoneal cancer index, completeness of cytoreduction (CC), and proliferative biological markers. RESULTS The rates of high/intermediate immunoreactivity were 95 % for topoisomerase IIα and 90 % for MCM7, and the median Ki-67 labeling index was 5 %. The independent predictors of OS were baseline serum albumin >3.5 g/dl, CC, and Ki-67 >5 %, whereas those for PFS were an ECOG performance status of 0, baseline serum albumin >3.5 g/dl, Charlson Comorbidity Index >3, previous systemic chemotherapy, morbidity G3-5, and Ki-67 >5 %. The remaining biological markers were not associated with outcome. CONCLUSIONS Ki-67 was found to be a new powerful determinant of outcome. Patients with a Ki-67 labeling index >5 % carry a very poor prognosis and do not benefit from the combined procedure. Further studies should be conducted to confirm the present data.
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Affiliation(s)
- Marcello Deraco
- Peritoneal Surface Malignancy Program, Department of Surgery, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Milan, Italy.
| | - Antonello Cabras
- Department of Pathology, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Milan, Italy
| | - Dario Baratti
- Peritoneal Surface Malignancy Program, Department of Surgery, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Milan, Italy
| | - Shigeki Kusamura
- Peritoneal Surface Malignancy Program, Department of Surgery, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Milan, Italy
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Adell E, Dejmek A. Telomerase activity analyzed with TRAP in situ provides additional information in effusions remaining equivocal after immunocytochemistry and hyaluronan analysis. Diagn Cytopathol 2014; 42:1051-7. [DOI: 10.1002/dc.23165] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 02/03/2014] [Accepted: 03/18/2014] [Indexed: 11/09/2022]
Affiliation(s)
- Elisabet Adell
- Clinical Pathology; University and Regional Laboratories, Region Skåne; SUS Malmö Sweden
| | - Annika Dejmek
- Clinical Pathology; University and Regional Laboratories, Region Skåne; SUS Malmö Sweden
- Department of Laboratory Medicine; Lund University; Malmö Sweden
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Overexpression and promoter mutation of the TERT gene in malignant pleural mesothelioma. Oncogene 2013; 33:3748-52. [DOI: 10.1038/onc.2013.351] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/19/2013] [Accepted: 07/22/2013] [Indexed: 12/22/2022]
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Delivery of chemotherapeutic drugs in tumour cell-derived microparticles. Nat Commun 2013; 3:1282. [PMID: 23250412 DOI: 10.1038/ncomms2282] [Citation(s) in RCA: 352] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 11/13/2012] [Indexed: 01/01/2023] Open
Abstract
Cellular microparticles are vesicular plasma membrane fragments with a diameter of 100-1,000 nanometres that are shed by cells in response to various physiological and artificial stimuli. Here we demonstrate that tumour cell-derived microparticles can be used as vectors to deliver chemotherapeutic drugs. We show that tumour cells incubated with chemotherapeutic drugs package these drugs into microparticles, which can be collected and used to effectively kill tumour cells in murine tumour models without typical side effects. We describe several mechanisms involved in this process, including uptake of drug-containing microparticles by tumour cells, synthesis of additional drug-packaging microparticles by these cells that contribute to the cytotoxic effect and the inhibition of drug efflux from tumour cells. This study highlights a novel drug delivery strategy with potential clinical application.
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Gocha ARS, Nuovo G, Iwenofu OH, Groden J. Human sarcomas are mosaic for telomerase-dependent and telomerase-independent telomere maintenance mechanisms: implications for telomere-based therapies. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 182:41-8. [PMID: 23260199 DOI: 10.1016/j.ajpath.2012.10.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 09/11/2012] [Accepted: 10/02/2012] [Indexed: 11/17/2022]
Abstract
Telomere shortening necessitates that tumor cells activate a telomere maintenance mechanism (TMM) to support immortalization. Although most tumor cells activate expression of the enzyme telomerase, some cells elongate telomeres in a telomerase-independent manner, termed alternative lengthening of telomeres (ALT). Previous studies have evaluated the presence of telomerase or ALT mechanisms or both in a variety of tumor types. Our studies also show that TMMs are not mutually exclusive in some tumors. In contrast, our IHC analyses of human sarcomas identified a subset of tumors with some cells containing ALT-associated PML bodies, a hallmark of ALT, and separate cells expressing telomerase in the same tumor. By using a second set of human osteosarcomas, we merged IHC and biochemical analyses to characterize more fully the tumor TMM. The IHC data reveal the presence of both telomerase- and ALT-positive tumor cells in samples that demonstrate characteristics of both telomerase and ALT in biochemical assays. These assays, which measure telomere length and telomerase activity of tumor extracts, are conventionally used to classify tumor TMM. Our results suggest that TMM is not a single or perhaps static characteristic of some tumors and that TMM heterogeneity should be considered in tumor stratification. Furthermore, clinical interest in telomere-based therapies may necessitate accurate characterization of tumor TMM before treatment to maximize therapeutic efficacy.
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Affiliation(s)
- April R S Gocha
- Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University College of Medicine, Columbus, Ohio, USA
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Samassekou O, Malina A, Hébert J, Yan J. Presence of alternative lengthening of telomeres associated circular extrachromosome telomere repeats in primary leukemia cells of chronic myeloid leukemia. J Hematol Oncol 2013; 6:26. [PMID: 23547895 PMCID: PMC3623713 DOI: 10.1186/1756-8722-6-26] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 03/23/2013] [Indexed: 11/12/2022] Open
Abstract
Background The predominant mechanism by which human tumors maintain telomere length is via telomerase. In ~10% of tumor samples, however, telomere length is conserved, despite no detectable telomerase activity, in part through activation of the alternative lengthening of telomeres (ALT) pathway. Methods We studied the circular extra-chromosomal telomeric repeat (ECTR), an ALT hallmark, and telomerase activity in 24 chronic myeloid leukemia (CML) patients in chronic phase (CP). Results We identified the presence of ECTR in primary leukemia cells from some of these samples, which indicates the possible involvement of an ALT mechanism. Moreover, we found that some samples exhibited both circular ECTR and telomerase activities, suggesting that both mechanisms can contribute to the onset of CML. Conclusion We propose that ALT or the combined activities of ALT and telomerase might be required for the early stages of leukemogenesis. These findings shed new light into the oncogenic pathways responsible for the maintenance of telomere length in leukemia, which will ultimately determine the effectiveness of anti-telomerase-based treatment protocols.
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Affiliation(s)
- Oumar Samassekou
- Division of Genetics, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
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Hung NA, Hsia H, Royds JA, Slatter TL. Telomere Maintenance Mechanisms: Prognostic and Therapeutic Implications for the Pathologist and Oncologist. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/ojpathology.2013.31003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Gocha ARS, Harris J, Groden J. Alternative mechanisms of telomere lengthening: permissive mutations, DNA repair proteins and tumorigenic progression. Mutat Res 2012; 743-744:142-150. [PMID: 23219603 DOI: 10.1016/j.mrfmmm.2012.11.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 11/22/2012] [Accepted: 11/24/2012] [Indexed: 01/05/2023]
Abstract
Telomeres protect chromosome termini to maintain genomic stability and regulate cellular lifespan. Maintenance of telomere length is required for neoplastic cells after the acquisition of mutations that deregulate cell cycle control and increase cellular proliferation, and can occur through expression of the enzyme telomerase or in a telomerase-independent manner termed alternative lengthening of telomeres (ALT). The precise mechanisms that govern the activation of ALT or telomerase in tumor cells are unknown, although cellular origin may favor one or the other mechanisms. ALT pathways are incompletely understood to date; however, recent publications have increasingly broadened our understanding of how ALT is activated, how it proceeds, and how it influences tumor growth. Specific mutational events influence ALT activation, as mutations in genes that suppress recombination and/or alterations in the regulation of telomerase expression are associated with ALT. Once engaged, ALT uses DNA repair proteins to maintain telomeres in the absence of telomerase; experiments that manipulate the expression of specific proteins in cells using ALT are illuminating some of its mechanisms. Furthermore, ALT may influence tumor growth, as experimental and clinical data suggest that telomerase expression may favor tumor progression. This review summarizes recent findings in mammalian cells and models, as well as clinical data, that identify the genetic mutations permissive to ALT, the DNA repair proteins involved in ALT mechanisms and the importance of telomere maintenance mechanisms for tumor progression. A comprehensive understanding of the mechanisms that permit tumor cell immortalization will be important for identifying novel therapeutic targets in cancer.
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Affiliation(s)
- April Renee Sandy Gocha
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University College of Medicine, Columbus, OH 43210, United States
| | - Julia Harris
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University College of Medicine, Columbus, OH 43210, United States
| | - Joanna Groden
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University College of Medicine, Columbus, OH 43210, United States.
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Jean D, Daubriac J, Le Pimpec-Barthes F, Galateau-Salle F, Jaurand MC. Molecular changes in mesothelioma with an impact on prognosis and treatment. Arch Pathol Lab Med 2012; 136:277-93. [PMID: 22372904 DOI: 10.5858/arpa.2011-0215-ra] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
CONTEXT In recent decades, research on malignant pleural mesothelioma (MPM) has been developed to improve patients' outcomes by increasing the level of confidence in MPM diagnosis and prognosis. OBJECTIVE To summarize data on genetic and epigenetic abnormalities in MPM that may be of interest for a better management of patients with MPM. DATA SOURCES Data were obtained from scientific publications on genetic and epigenetic abnormalities in MPM by studying gene mutations, DNA methylation, and gene and microRNA expression profiling. CONCLUSIONS Molecular changes in MPM consist in altered expression and in activation or inactivation of critical genes in oncogenesis, especially tumor suppressor genes at the INK4 and NF2 loci. Activation of membrane receptor tyrosine kinases and deregulation of signaling pathways related to differentiation, survival, proliferation, apoptosis, cell cycle control, metabolism, migration, and invasion have been demonstrated. Alterations that could be targeted at a global level (methylation) have been recently reported. Experimental research has succeeded especially in abolishing proliferation and triggering apoptosis in MPM cells. So far, targeted clinical approaches focusing on receptor tyrosine kinases have had limited success. Molecular analyses of series of MPM cases have shown that defined alterations are present in MPM subsets, consistent with interindividual variations of molecular alterations, and suggesting that identification of patient subgroups will be essential to develop more specific therapies.
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Affiliation(s)
- Didier Jean
- INSERM, U, Université Paris Descartes, UMR-S, Paris, France
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Venturini L, Daidone MG, Motta R, Cimino-Reale G, Hoare SF, Gronchi A, Folini M, Keith WN, Zaffaroni N. Telomere maintenance mechanisms in malignant peripheral nerve sheath tumors: expression and prognostic relevance. Neuro Oncol 2012; 14:736-44. [PMID: 22516689 DOI: 10.1093/neuonc/nos083] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
This study investigated the prevalence and the prognostic relevance of the 2 known telomere maintenance mechanisms (TMMs), telomerase activity (TA) and alternative lengthening of telomeres (ALT), in malignant peripheral nerve sheath tumors (MPNST). In 57 specimens from 49 patients with MPNST (35 sporadic, 14 neurofibromatosis type 1-related), TA was determined using the telomeric repeat amplification protocol, and ALT was detected by assaying ALT-associated promyelocytic leukemia bodies (APB) and terminal restriction fragment (TRF) length distribution. TA or ALT (defined on the basis of APB) alone was found in 24.6% or 26.3% of the lesions, respectively, whereas 6 cases (10.5%) were TA+/ALT+. A concordance between APB and TRF results in defining the ALT status was observed in 44 of 57 cases (77.2%; P < .0001). TA was more frequently expressed in samples from patients with neurofibromatosis type 1 than in those with sporadic disease (60% vs 29.4%, P = 0.087). In the overall series, TA proved to be prognostic for 5-year disease-specific death (hazard ratio, 3.78; 95% confidence interval [CI], 1.60-8.95; P = .002), even when adjusted for the presence of neurofibromatosis type 1 (hazard ratio, 4.22; 95% CI, 1.804-9.874; P = .001) and margin status after surgery (hazard ratio, 5.78; 95% CI, 2.19-15.26; P < .001). Conversely, ALT did not significantly affect clinical outcome of MPNST using either APB expression (hazard ratio, 1.25; 95% CI 0.54-2.89; P = 0.605) or TRF distribution (hazard ratio, 0.57; 95% CI, 0.17-1.96; P = .375) as the detection approach. Our results indicate for the first time that both TMMs, TA and ALT, are present in MPNST and differentially affect patient prognosis.
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Affiliation(s)
- Lorenza Venturini
- Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
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Modulation of telomeres in alternative lengthening of telomeres type I like human cells by the expression of werner protein and telomerase. JOURNAL OF ONCOLOGY 2012; 2012:806382. [PMID: 22545052 PMCID: PMC3321466 DOI: 10.1155/2012/806382] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 12/13/2011] [Accepted: 01/10/2012] [Indexed: 02/06/2023]
Abstract
The alternative lengthening of telomeres (ALT) is a recombination-based mechanism of telomere maintenance activated in 5–20% of human cancers. In Saccharomyces cerevisiae, survivors that arise after inactivation of telomerase can be classified as type I or type II ALT. In type I, telomeres have a tandem array structure, with each subunit consisting of a subtelomeric Y′ element and short telomere sequence. Telomeres in type II have only long telomere repeats and require Sgs1, the S. cerevisiae RecQ family helicase. We previously described the first human ALT cell line, AG11395, that has a telomere structure similar to type I ALT yeast cells. This cell line lacks the activity of the Werner syndrome protein, a human RecQ helicase. The telomeres in this cell line consist of tandem repeats containing SV40 DNA, including the origin of replication, and telomere sequence. We investigated the role of the SV40 origin of replication and the effects of Werner protein and telomerase on telomere structure and maintenance in AG11395 cells. We report that the expression of Werner protein facilitates the transition in human cells of ALT type I like telomeres to type II like telomeres in some aspects. These findings have implications for the diagnosis and treatment of cancer.
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Durant ST. Telomerase-independent paths to immortality in predictable cancer subtypes. J Cancer 2012; 3:67-82. [PMID: 22315652 PMCID: PMC3273709 DOI: 10.7150/jca.3965] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 01/28/2012] [Indexed: 01/17/2023] Open
Abstract
The vast majority of cancers commandeer the activity of telomerase - the remarkable enzyme responsible for prolonging cellular lifespan by maintaining the length of telomeres at the ends of chromosomes. Telomerase is only normally active in embryonic and highly proliferative somatic cells. Thus, targeting telomerase is an attractive anti-cancer therapeutic rationale currently under investigation in various phases of clinical development. However, previous reports suggest that an average of 10-15% of all cancers lose the functional activity of telomerase and most of these turn to an Alternative Lengthening of Telomeres pathway (ALT). ALT-positive tumours will therefore not respond to anti-telomerase therapies and there is a real possibility that such drugs would be toxic to normal telomerase-utilising cells and ultimately select for resistant cells that activate an ALT mechanism. ALT exploits certain DNA damage response (DDR) components to counteract telomere shortening and rapid trimming. ALT has been reported in many cancer subtypes including sarcoma, gastric carcinoma, central nervous system malignancies, subtypes of kidney (Wilm's Tumour) and bladder carcinoma, mesothelioma, malignant melanoma and germ cell testicular cancers to name but a few. A recent heroic study that analysed ALT in over six thousand tumour samples supports this historical spread, although only reporting an approximate 4% prevalence. This review highlights the various methods of ALT detection, unravels several molecular ALT models thought to promote telomere maintenance and elongation, spotlights the DDR components known to facilitate these and explores why certain tissues are more likely to subvert DDR away from its usually protective functions, resulting in a predictive pattern of prevalence in specific cancer subsets.
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Affiliation(s)
- Stephen T Durant
- AstraZeneca - DNA Damage Response, Bioscience, Oncology iMed, Alderley Park, Cheshire, SK10 4TG, England, UK
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Venturini L, Daidone MG, Motta R, Collini P, Spreafico F, Terenziani M, Piva L, Radice P, Perotti D, Zaffaroni N. Telomere maintenance in wilms tumors: First evidence for the presence of alternative lengthening of telomeres mechanism. Genes Chromosomes Cancer 2011; 50:823-9. [DOI: 10.1002/gcc.20903] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 06/10/2011] [Indexed: 11/08/2022] Open
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Syntenic relationships between genomic profiles of fiber-induced murine and human malignant mesothelioma. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:881-94. [PMID: 21281820 DOI: 10.1016/j.ajpath.2010.10.039] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 09/27/2010] [Accepted: 10/21/2010] [Indexed: 11/22/2022]
Abstract
Malignant mesothelioma (MM) is an aggressive tumor with a poor prognosis mainly linked to past asbestos exposure. Murine models of MM based on fiber exposure have been developed to elucidate the mechanism of mesothelioma formation. Genomic alterations in murine MM have now been partially characterized. To gain insight into the pathophysiology of mesothelioma, 16 murine and 35 human mesotheliomas were characterized by array-comparative genomic hybridization and were screened for common genomic alterations. Alteration of the 9p21 human region, often by biallelic deletion, was the most frequent alteration in both species, in agreement with the CDKN2A/CDKN2B locus deletion in human disease and murine models. Other shared aberrations were losses of 1p36.3-p35 and 13q14-q33 and gains of 5p15.3-p13 regions. However, some differences were noted, such as absence of recurrent alterations in mouse regions corresponding to human chromosome 22. Comparison between altered recurrent regions in asbestos-exposed and non-asbestos-exposed patients showed a significant difference in the 14q11.2-q21 region, which was also lost in fiber-induced murine mesothelioma. A correlation was also demonstrated between genomic instability and tumorigenicity of human mesothelioma xenografts in nude mice. Overall, these data show similarities between murine and human disease, and contribute to the understanding of the influence of fibers in the pathogenesis of mesothelioma and validation of the murine model for preclinical testing.
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Folini M, Venturini L, Cimino-Reale G, Zaffaroni N. Telomeres as targets for anticancer therapies. Expert Opin Ther Targets 2011; 15:579-93. [DOI: 10.1517/14728222.2011.556621] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Lobetti-Bodoni C, Bernocco E, Genuardi E, Boccadoro M, Ladetto M. Telomeres and telomerase in normal and malignant B-cells. Hematol Oncol 2011; 28:157-67. [PMID: 20213664 DOI: 10.1002/hon.937] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The telomeric checkpoint is emerging as a critical sensor of cellular damage, playing a major role in human aging and cancer development. In the meantime, telomere biology is rapidly evolving from a basic discipline to a translational branch, capable of providing major hints for biomarker development, risk assessment and targeted treatment of cancer. These advances have a number of implications in the biology of lymphoid tumours. Moreover, there is considerable interest in the potential role of telomeric dysfunction in the wide array of immunological abnormalities, grouped under the definition of 'immunosenescence'. This review will summarize the impact of recent advances in telomere biology on the physiology and pathology of the B lymphocyte, with special interest in immunosenescence and lymphomagenesis.
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Affiliation(s)
- Chiara Lobetti-Bodoni
- Department of Experimental Oncology, Division of Hematology, University of Torino, Italy
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Baratti D, Kusamura S, Deraco M. Diffuse malignant peritoneal mesothelioma: systematic review of clinical management and biological research. J Surg Oncol 2011; 103:822-31. [PMID: 21283990 DOI: 10.1002/jso.21787] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 09/21/2010] [Indexed: 01/30/2023]
Abstract
Diffuse malignant peritoneal mesothelioma (DMPM) is an uncommon and locally aggressive tumor with poor prognosis. Currently, no standard therapy is available. The biology of this disease is still poorly understood. We performed a systematic search of relevant studies on clinical management and biological research of DMPM. Trials were selected using a predetermined protocol. The current evidence suggests that cytoreductive surgery (CRS) and perioperative intraperitoneal chemotherapy (PIC) results in improved survival. Biological understanding of DMPM is currently evolving.
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Affiliation(s)
- Dario Baratti
- Department of Surgery, National Cancer Institute, Milan, Italy
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Au AYM, Hackl T, Yeager TR, Cohen SB, Pass HI, Harris CC, Reddel RR. Telomerase activity in pleural malignant mesotheliomas. Lung Cancer 2011; 73:283-8. [PMID: 21277646 DOI: 10.1016/j.lungcan.2010.12.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 12/18/2010] [Indexed: 12/16/2022]
Abstract
New treatments are needed for malignant pleural mesothelioma (MPM), which currently has a poor prognosis. Cellular immortalisation, one of the hallmarks of cancer, depends on the activity of a telomere length maintenance mechanism (TMM) - either telomerase or alternative lengthening of telomeres (ALT). The TMMs are widely regarded as potential targets for cancer therapies and telomerase inhibitors have entered clinical trials. The aim of this study was to determine what proportion of MPMs use ALT and/or telomerase. Forty-three MPMs from 42 patients were examined for telomerase and ALT activity. Telomerase activity was detected by immunoaffinity purification followed by the telomere repeat amplification protocol (TRAP), and ALT activity was determined by the C-circle assay and by assessing telomere lengths using terminal restriction fragment analyses. We found that 43 of 43 MPMs were telomerase-positive[+] and ALT-negative[-]. Therefore, to investigate whether pleural mesothelial cells are unusually susceptible to activation of telomerase, we examined activation of the TMMs in an in vitro model of cellular immortalisation, in which normal pleural mesothelial cells were transduced with simian virus 40 (SV40) oncogenes. We found that normal mesothelial cells were TMM-negative, and that expression of the SV40 oncogenes did not directly activate telomerase or ALT. Immortalisation, which in this experimental system results from additional genetic changes that have not yet been identified, was accompanied by activation of either TMM. Therefore, pleural mesothelial cells are capable of activating either TMM in vitro, and the observation that 100% of MPMs were telomerase[+] suggests that there are factors in vivo that select for telomerase activity during oncogenesis of this tumour type. We conclude that MPM is a tumour that could be considered for anti-telomerase therapy.
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Affiliation(s)
- Amy Y M Au
- Children's Medical Research Institute, 214 Hawkesbury Road, Westmead, New South Wales 2145, Australia
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Lafferty-Whyte K, Bilsland A, Cairney CJ, Hanley L, Jamieson NB, Zaffaroni N, Oien KA, Burns S, Roffey J, Boyd SM, Keith WN. Scoring of senescence signalling in multiple human tumour gene expression datasets, identification of a correlation between senescence score and drug toxicity in the NCI60 panel and a pro-inflammatory signature correlating with survival advantage in peritoneal mesothelioma. BMC Genomics 2010; 11:532. [PMID: 20920304 PMCID: PMC3091681 DOI: 10.1186/1471-2164-11-532] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Accepted: 10/01/2010] [Indexed: 11/10/2022] Open
Abstract
Background Cellular senescence is a major barrier to tumour progression, though its role in pathogenesis of cancer and other diseases is poorly understood in vivo. Improved understanding of the degree to which latent senescence signalling persists in tumours might identify intervention strategies to provoke "accelerated senescence" responses as a therapeutic outcome. Senescence involves convergence of multiple pathways and requires ongoing dynamic signalling throughout its establishment and maintenance. Recent discovery of several new markers allows for an expression profiling approach to study specific senescence phenotypes in relevant tissue samples. We adopted a "senescence scoring" methodology based on expression profiles of multiple senescence markers to examine the degree to which signals of damage-associated or secretory senescence persist in various human tumours. Results We first show that scoring captures differential induction of damage or inflammatory pathways in a series of public datasets involving radiotherapy of colon adenocarcinoma, chemotherapy of breast cancer cells, replicative senescence of mesenchymal stem cells, and progression of melanoma. We extended these results to investigate correlations between senescence score and growth inhibition in response to ~1500 compounds in the NCI60 panel. Scoring of our own mesenchymal tumour dataset highlighted differential expression of secretory signalling pathways between distinct subgroups of MPNST, liposarcomas and peritoneal mesothelioma. Furthermore, a pro-inflammatory signature yielded by hierarchical clustering of secretory markers showed prognostic significance in mesothelioma. Conclusions We find that "senescence scoring" accurately reports senescence signalling in a variety of situations where senescence would be expected to occur and highlights differential expression of damage associated and secretory senescence pathways in a context-dependent manner.
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Affiliation(s)
- Kyle Lafferty-Whyte
- Centre for Oncology and Applied Pharmacology, University of Glasgow, Cancer Research UK Beatson Laboratories, Garscube Estate, Switchback Road, Bearsden, Glasgow G611BD, UK
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TCEAL7 inhibition of c-Myc activity in alternative lengthening of telomeres regulates hTERT expression. Neoplasia 2010; 12:405-14. [PMID: 20454512 DOI: 10.1593/neo.10180] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 03/03/2010] [Accepted: 03/05/2010] [Indexed: 11/18/2022] Open
Abstract
Replicative senescence forms a major barrier to tumor progression. Cancer cells bypass this by using one of the two known telomere maintenance mechanisms: telomerase or the recombination-based alternative lengthening of telomeres (ALT) mechanism. The molecular details of ALT are currently poorly understood. We have previously shown that telomerase is actively repressed through complex networks of kinase, gene expression, and chromatin regulation. In this study, we aimed to gain further understanding of the role of kinases in the regulation of telomerase expression in ALT cells. Using a whole human kinome small interfering RNA (siRNA) screen, we highlighted 106 kinases whose expression is linked to human telomerase reverse transcriptase (hTERT) promoter activity. Network modeling of transcriptional regulation implicated c-Myc as a key regulator of the 106 kinase hits. Given our previous observations of lower c-Myc activity in ALT cells, we further explored its potential to regulate telomerase expression in ALT. We found increased c-Myc binding at the hTERT promoter in telomerase-positive compared with ALT cells, although no expression differences in c-Myc, Mad, or Max were observed between ALT and telomerase-positive cells that could explain decreased c-Myc activity in ALT. Instead, we found increased expression of the c-Myc competitive inhibitor TCEAL7 in ALT cells and tumors and that alteration of TCEAL7 expression levels in ALT and telomerase-positive cells affects hTERT expression. Lower c-Myc activity in ALT may therefore be obtained through TCEAL7 regulation. Thus, TCEAL7 may present an interesting novel target for cancer therapy, which warrants further investigation.
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Receptor tyrosine kinase and downstream signalling analysis in diffuse malignant peritoneal mesothelioma. Eur J Cancer 2010; 46:2837-48. [PMID: 20692828 DOI: 10.1016/j.ejca.2010.06.130] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 06/22/2010] [Accepted: 06/24/2010] [Indexed: 11/22/2022]
Abstract
Our aim was to assess the activation profile of EGFR, PDGFRB and PDGFRA receptor tyrosine kinases (RTK) and their downstream effectors in a series of cryopreserved diffuse malignant peritoneal mesothelioma (DMPM) surgical specimens to discover the targets for drug inhibition. We also made a complementary analysis of the cytotoxic effects of some kinase inhibitors on the proliferation of the human peritoneal mesothelioma STO cell line. We found the expression/phosphorylation of EGFR and PDGFRB in most of the tumours, and PDGFRA activation in half. The expression of the cognate ligands TGF-α, PDGFB and PDGFA in the absence of RTK mutation and amplification suggested the presence of an autocrine/paracrine loop. There was also evidence of EGFR and PDGFRB co-activation. RTK downstream signalling analysis demonstrated the activation/expression of ERK1/2, AKT and mTOR, together with S6 and 4EBP1, in almost all the DMPMs. No KRAS/BRAF mutations, PI3KCA mutations/amplifications or PTEN inactivation were observed. Real-time polymerase chain reaction revealed the decreased expression of TSC1 c-DNA in half of the tumours. In vitro cytotoxicity studies showed the STO cell line to be resistant to gefitinib and sensitive to sequential treatment with RAD001 and sorafenib; these findings were consistent with the presence of the KRAS mutation G12D in these cells although it was not detectable in the original tumour. Our results highlight the ligand-dependent activation and co-activation of EGFR and PDGFRB, as well as a connection between these activated RTKs and the downstream mTOR pathway, thus supporting the role of combined treatment with RTK and mTOR inhibitors in DMPM.
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Henson JD, Reddel RR. Assaying and investigating Alternative Lengthening of Telomeres activity in human cells and cancers. FEBS Lett 2010; 584:3800-11. [PMID: 20542034 DOI: 10.1016/j.febslet.2010.06.009] [Citation(s) in RCA: 176] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 06/08/2010] [Indexed: 12/14/2022]
Abstract
Alternative Lengthening of Telomeres (ALT) activity can be deduced from the presence of telomere length maintenance in the absence of telomerase activity. More convenient assays for ALT utilize phenotypic markers of ALT activity, but only a few of these assays are potentially definitive. Here we assess each of the current ALT assays and their implications for understanding the ALT mechanism. We also review the clinical situations where availability of an ALT activity assay would be advantageous. The prevalence of ALT ranges from 25% to 60% in sarcomas and 5% to 15% in carcinomas. Patients with many of these types of ALT[+] tumors have a poor prognosis.
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Affiliation(s)
- Jeremy D Henson
- Children's Medical Research Institute, Sydney, NSW, Australia
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46
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Bone osteoblastic and mesenchymal stromal cells lack primarily tumoral features in multiple myeloma patients. Leukemia 2010; 24:1368-70. [PMID: 20485369 DOI: 10.1038/leu.2010.96] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Unlimited cellular proliferation depends on counteracting the telomere attrition that accompanies DNA replication. In human cancers this usually occurs through upregulation of telomerase activity, but in 10-15% of cancers - including some with particularly poor outcome - it is achieved through a mechanism known as alternative lengthening of telomeres (ALT). ALT, which is dependent on homologous recombination, is therefore an important target for cancer therapy. Although dissection of the mechanism or mechanisms of ALT has been challenging, recent advances have led to the identification of several genes that are required for ALT and the elucidation of the biological significance of some phenotypic markers of ALT. This has enabled development of a rapid assay of ALT activity levels and the construction of molecular models of ALT.
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Deraco M, Baratti D, Cabras AD, Zaffaroni N, Perrone F, Villa R, Jocollè J, Balestra MR, Kusamura S, Laterza B, Pilotti S. Experience with peritoneal mesothelioma at the Milan National Cancer Institute. World J Gastrointest Oncol 2010; 2:76-84. [PMID: 21160925 PMCID: PMC2999160 DOI: 10.4251/wjgo.v2.i2.76] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 11/06/2009] [Accepted: 11/13/2009] [Indexed: 02/05/2023] Open
Abstract
Diffuse malignant peritoneal mesothelioma (DMPM) is an uncommon and rapidly fatal tumor. Therapeutic options have traditionally been limited and ineffective. The biologic and molecular events correlated with poor responsiveness to therapy are still poorly understood. In recent years, an innovative treatment approach involving aggressive cytoreductive surgery (CRS) and perioperative intraperitoneal chemotherapy has reportedly resulted in improved outcome, as compared to historical controls. Since 1995, at the National Cancer Institute (NCI) of Milan (Italy), patients with DMPM have been treated with CRS and hyperthermic intra-peritoneal chemotherapy (HIPEC). In the present paper, clinical experiences and basic science investigations on DMPM at Milan NCI are reviewed. Peri-operative and long-term outcome results with CRS and HIPEC are presented. Clinico-pathological prognostic factors were investigated by multivariate analysis. The pathologic features and immunohistochemical markers related to DMPM biologic behavior were assessed in a large case-series uniformly treated at our institution. The prevalence and prognostic role of telomere maintenance mechanisms, which account for the limitless cell replicative potential of many malignancies, were studied. The dysregulation of the apoptotic pathways may play a role in the relative chemo-resistance of DMPM and a better understanding of apoptosis-related mechanisms could result in novel targeted therapeutic strategies. On this basis, the expression of survivin and other IAP family members (IAP-1, IAP-2, and X-IAP), the pro-apoptotic protein Smac/DIABLO, and antigens associated with cell proliferation (Ki-67) and apoptosis (caspase-cleaved cytokeratin-18) were analyzed. Finally, analyses of EGFR, PDGFRA and PDGFRB were performed to ascertain if deregulation of RTK could offer useful alternative therapeutic targets.
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Affiliation(s)
- Marcello Deraco
- Marcello Deraco, Dario Baratti, Maria Rosaria Balestra, Shigeki Kusamura, Barbara Laterza, Department of Surgery, National Cancer Institute, 20133 Milan, Italy
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Kusamura S, Baratti D, Zaffaroni N, Villa R, Laterza B, Balestra MR, Deraco M. Pathophysiology and biology of peritoneal carcinomatosis. World J Gastrointest Oncol 2010; 2:12-8. [PMID: 21160812 PMCID: PMC2999153 DOI: 10.4251/wjgo.v2.i1.12] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 10/07/2009] [Accepted: 10/14/2009] [Indexed: 02/05/2023] Open
Abstract
Peritoneal carcinomatosis represents a devastating form of cancer progression with a very poor prognosis. Its complex pathogenesis is represented by a dynamic process comprising several steps. To the best of our knowledge pathogenesis can be partly explained by 3 major molecular pathways: (1) dissemination from the primary tumor; (2) primary tumor of peritoneum; and (3) independent origins of the primary tumor and peritoneal implants. These are not mutually exclusive and combinations of different mechanisms could occur inside a single case. There are still several aspects which need explanation by future studies. A comprehensive understanding of molecular events involved in peritoneal carcinomatosis is of paramount importance and should be systematically pursued not only to identify novel strategies for the prevention of the condition, but also to obtain therapeutic advances, through the identification of surrogate markers of prognosis and development of future molecular targeted therapies.
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Affiliation(s)
- Shigeki Kusamura
- Shigeki Kusamura, Dario Baratti, Barbara Laterza, Maria Rosaria Balestra, Marcello Deraco, Department of Surgery, National Cancer Institute of Milan, Via Venezian 1, 20133 Milano, Italy
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Abstract
Normal mammalian somatic cells proliferate a finite number of times in vitro before permanently withdrawing from the cell cycle into a cellular state referred to as senescence. Senescence may be triggered by excessive mitogenic stimulation or by various forms of cellular damage including excessive telomere shortening. Over the past decade, there has been continuing accumulation of evidence that senescence occurs in vivo, that it is relevant to aging and that it has a tumor suppressor function. However, the phenotype of senescence has also been found to include a number of puzzling features, including the secretion of proinflammatory factors that may foster tumorigenesis as well as the senescence of neighboring cells. On the basis of these antagonistic pro- and antitumorigenic effects, and of the observation that many viruses have developed proteins that prevent senescence of the cells they infect, it is argued that the primary function of senescence may have been as an antiviral defense mechanism. Recent progress in understanding how tumor cells evade senescence is also reviewed here.
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Affiliation(s)
- Roger R Reddel
- Cancer Research Unit, Children's Medical Research Institute, 214 Hawkesbury Road, Westmead, New South Wales 2145, Australia.
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