1
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Pinto LM, Pailas A, Bondarchenko M, Sharma AB, Neumann K, Rizzo AJ, Jeanty C, Nicot N, Racca C, Graham MK, Naughton C, Liu Y, Chen CL, Meakin PJ, Gilbert N, Britton S, Meeker AK, Heaphy CM, Larminat F, Van Dyck E. DAXX promotes centromeric stability independently of ATRX by preventing the accumulation of R-loop-induced DNA double-stranded breaks. Nucleic Acids Res 2024; 52:1136-1155. [PMID: 38038252 PMCID: PMC10853780 DOI: 10.1093/nar/gkad1141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 11/08/2023] [Accepted: 11/13/2023] [Indexed: 12/02/2023] Open
Abstract
Maintaining chromatin integrity at the repetitive non-coding DNA sequences underlying centromeres is crucial to prevent replicative stress, DNA breaks and genomic instability. The concerted action of transcriptional repressors, chromatin remodelling complexes and epigenetic factors controls transcription and chromatin structure in these regions. The histone chaperone complex ATRX/DAXX is involved in the establishment and maintenance of centromeric chromatin through the deposition of the histone variant H3.3. ATRX and DAXX have also evolved mutually-independent functions in transcription and chromatin dynamics. Here, using paediatric glioma and pancreatic neuroendocrine tumor cell lines, we identify a novel ATRX-independent function for DAXX in promoting genome stability by preventing transcription-associated R-loop accumulation and DNA double-strand break formation at centromeres. This function of DAXX required its interaction with histone H3.3 but was independent of H3.3 deposition and did not reflect a role in the repression of centromeric transcription. DAXX depletion mobilized BRCA1 at centromeres, in line with BRCA1 role in counteracting centromeric R-loop accumulation. Our results provide novel insights into the mechanisms protecting the human genome from chromosomal instability, as well as potential perspectives in the treatment of cancers with DAXX alterations.
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Affiliation(s)
- Lia M Pinto
- DNA Repair and Chemoresistance Group, Department of Cancer Research, Luxembourg Institute of Health (LIH), L-1210 Luxembourg, Luxembourg
- Faculty of Science, Technology and Communication, University of Luxembourg, L-4365 Esch-sur-Alzette, Luxembourg
- Discovery & Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, UK
| | - Alexandros Pailas
- DNA Repair and Chemoresistance Group, Department of Cancer Research, Luxembourg Institute of Health (LIH), L-1210 Luxembourg, Luxembourg
- Faculty of Science, Technology and Communication, University of Luxembourg, L-4365 Esch-sur-Alzette, Luxembourg
| | - Max Bondarchenko
- DNA Repair and Chemoresistance Group, Department of Cancer Research, Luxembourg Institute of Health (LIH), L-1210 Luxembourg, Luxembourg
- Faculty of Science, Technology and Communication, University of Luxembourg, L-4365 Esch-sur-Alzette, Luxembourg
| | - Abhishek Bharadwaj Sharma
- DNA Repair and Chemoresistance Group, Department of Cancer Research, Luxembourg Institute of Health (LIH), L-1210 Luxembourg, Luxembourg
| | - Katrin Neumann
- DNA Repair and Chemoresistance Group, Department of Cancer Research, Luxembourg Institute of Health (LIH), L-1210 Luxembourg, Luxembourg
| | - Anthony J Rizzo
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Céline Jeanty
- DNA Repair and Chemoresistance Group, Department of Cancer Research, Luxembourg Institute of Health (LIH), L-1210 Luxembourg, Luxembourg
| | - Nathalie Nicot
- Translational Medicine Operations Hub, Luxembourg Institute of Health (LIH), Luxembourg, Luxembourg
| | - Carine Racca
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), 31077 Toulouse Cedex 4, France
| | - Mindy K Graham
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Catherine Naughton
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh EH4 1QY, UK
| | - Yaqun Liu
- Institut Curie, PSL Research University, CNRS UMR3244, Dynamics of Genetic Information, Sorbonne Université, 75248 Paris Cedex 05, France
| | - Chun-Long Chen
- Institut Curie, PSL Research University, CNRS UMR3244, Dynamics of Genetic Information, Sorbonne Université, 75248 Paris Cedex 05, France
| | - Paul J Meakin
- Discovery & Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, UK
| | - Nick Gilbert
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh EH4 1QY, UK
| | - Sébastien Britton
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), 31077 Toulouse Cedex 4, France
| | - Alan K Meeker
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Christopher M Heaphy
- Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Florence Larminat
- Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), 31077 Toulouse Cedex 4, France
| | - Eric Van Dyck
- DNA Repair and Chemoresistance Group, Department of Cancer Research, Luxembourg Institute of Health (LIH), L-1210 Luxembourg, Luxembourg
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2
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Cosgrove BD, Bounds LR, Taylor CK, Su AL, Rizzo AJ, Barrera A, Crawford GE, Hoffman BD, Gersbach CA. Mechanosensitive genomic enhancers potentiate the cellular response to matrix stiffness. bioRxiv 2024:2024.01.10.574997. [PMID: 38260455 PMCID: PMC10802421 DOI: 10.1101/2024.01.10.574997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Epigenetic control of cellular transcription and phenotype is influenced by changes in the cellular microenvironment, yet how mechanical cues from these microenvironments precisely influence epigenetic state to regulate transcription remains largely unmapped. Here, we combine genome-wide epigenome profiling, epigenome editing, and phenotypic and single-cell RNA-seq CRISPR screening to identify a new class of genomic enhancers that responds to the mechanical microenvironment. These 'mechanoenhancers' could be active on either soft or stiff extracellular matrix contexts, and regulated transcription to influence critical cell functions including apoptosis, mechanotransduction, proliferation, and migration. Epigenetic editing of mechanoenhancers on rigid materials tuned gene expression to levels observed on softer materials, thereby reprogramming the cellular response to the mechanical microenvironment. These editing approaches may enable the precise alteration of mechanically-driven disease states.
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Affiliation(s)
- Brian D. Cosgrove
- Department of Biomedical Engineering, Duke University; Durham, NC 27708, USA
- Center for Advanced Genomic Technologies, Duke University; Durham, NC 27708, USA
| | - Lexi R. Bounds
- Department of Biomedical Engineering, Duke University; Durham, NC 27708, USA
- Center for Advanced Genomic Technologies, Duke University; Durham, NC 27708, USA
| | - Carson Key Taylor
- Department of Biomedical Engineering, Duke University; Durham, NC 27708, USA
- Center for Advanced Genomic Technologies, Duke University; Durham, NC 27708, USA
| | - Alan L. Su
- Department of Biomedical Engineering, Duke University; Durham, NC 27708, USA
- Center for Advanced Genomic Technologies, Duke University; Durham, NC 27708, USA
| | - Anthony J. Rizzo
- Department of Biomedical Engineering, Duke University; Durham, NC 27708, USA
- Center for Advanced Genomic Technologies, Duke University; Durham, NC 27708, USA
| | - Alejandro Barrera
- Center for Advanced Genomic Technologies, Duke University; Durham, NC 27708, USA
- Department of Biostatistics and Bioinformatics, Duke University; Durham, NC 27708, USA
| | - Gregory E. Crawford
- Center for Advanced Genomic Technologies, Duke University; Durham, NC 27708, USA
- Department of Pediatrics, Duke University Medical Center; Durham, NC 27708, USA
| | - Brenton D. Hoffman
- Department of Biomedical Engineering, Duke University; Durham, NC 27708, USA
- Department of Cell Biology, Duke University; Durham, NC 27708, USA
| | - Charles A. Gersbach
- Department of Biomedical Engineering, Duke University; Durham, NC 27708, USA
- Center for Advanced Genomic Technologies, Duke University; Durham, NC 27708, USA
- Department of Cell Biology, Duke University; Durham, NC 27708, USA
- Department of Surgery, Duke University Medical Center; Durham, NC 27708, USA
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3
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Brosnan-Cashman JA, Graham MK, Rizzo AJ, Myers K, Zhang R, Göger E, Zarinshenas R, Davis C, Yuan M, Rakheja D, Raabe EH, Eberhart CG, Heaphy CM, Meeker AK. Abstract B14: Establishment and characterization of in vitro models of alternative lengthening of telomeres (ALT) in pediatric high-grade glioma. Cancer Res 2018. [DOI: 10.1158/1538-7445.pedca17-b14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Telomeres consist of many kilobases of repeated TTAGGG sequences at the ends of chromosomes, protected by a sequence-specific protein cap. Telomeres progressively shorten with each cell division and ultimately become critically short; due to their extensive proliferation, cancer cells must find a way to counteract this telomere loss. While most cancers utilize telomerase to maintain their telomere length, about 5% of cancers use a telomerase-independent telomere maintenance strategy, termed alternative lengthening of telomeres (ALT). While, overall, ALT is rare in cancer (~5-10% of cases), this telomere maintenance mechanism is enriched in pediatric high-grade glioma (pHGG). Previous work in our laboratory suggests that nearly half of pHGG utilize ALT. To date, therapeutic options are largely ineffective for children with HGG, reflected in the five-year survival rate, which is less than 33%. Our goal is to better harness ALT as a clinical marker in pHGG, specifically by the identification of drugs that target ALT-positive cancers. In order to study ALT in this context, we obtained and characterized a panel of six pHGG cell lines. Two of these six pHGG cell lines displayed features of ALT, including the presence of ALT-associated PML bodies and extrachromosomal telomeric DNA in the form of c-circles. Furthermore, these lines lacked measurable telomerase activity. It is well established that ATRX is commonly mutated in ALT-positive cancers, including pHGG. Interestingly, only one of these two ALT-positive pHGG cell lines displayed total loss of ATRX; the second cell line has an in-frame deletion in the ATRX gene, which may provide insight into the mechanism of how ATRX acts to suppress ALT. In addition, we have generated ATRX knockout cell lines from the four ALT-negative pHGG cells identified in this panel. Despite the strong link between ATRX loss and ALT in clinical samples, only one cell line displayed ALT characteristics after ATRX knockout. Comparison of the ALT-competent cell line to the ALT-resistant cell lines will yield important information about additional genetic or epigenetic events that allow ALT to occur. In conclusion, we have established in vitro models of ALT in pHGG cell lines based on endogenous ALT positivity and induction of ALT-like features based on ATRX modulation. These models will be invaluable resources as we strive to understand the molecular characteristics of ALT and translate these findings to better therapies for children with pHGG.
Citation Format: Jacqueline A. Brosnan-Cashman, Mindy K. Graham, Anthony J. Rizzo, Kaylar Myers, Rebecca Zhang, Ezgi Göger, Reza Zarinshenas, Christine Davis, Ming Yuan, Dinesh Rakheja, Eric H. Raabe, Charles G. Eberhart, Christopher M. Heaphy, Alan K. Meeker. Establishment and characterization of in vitro models of alternative lengthening of telomeres (ALT) in pediatric high-grade glioma [abstract]. In: Proceedings of the AACR Special Conference: Pediatric Cancer Research: From Basic Science to the Clinic; 2017 Dec 3-6; Atlanta, Georgia. Philadelphia (PA): AACR; Cancer Res 2018;78(19 Suppl):Abstract nr B14.
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Affiliation(s)
| | - Mindy K. Graham
- 1Johns Hopkins University School of Medicine, Baltimore, MD,
| | | | - Kaylar Myers
- 1Johns Hopkins University School of Medicine, Baltimore, MD,
| | - Rebecca Zhang
- 1Johns Hopkins University School of Medicine, Baltimore, MD,
| | - Ezgi Göger
- 1Johns Hopkins University School of Medicine, Baltimore, MD,
| | | | - Christine Davis
- 1Johns Hopkins University School of Medicine, Baltimore, MD,
| | - Ming Yuan
- 1Johns Hopkins University School of Medicine, Baltimore, MD,
| | - Dinesh Rakheja
- 2University of Texas Southwestern Medical Center, Dallas, TX
| | - Eric H. Raabe
- 1Johns Hopkins University School of Medicine, Baltimore, MD,
| | | | | | - Alan K. Meeker
- 1Johns Hopkins University School of Medicine, Baltimore, MD,
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4
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Brosnan-Cashman JA, Yuan M, Graham MK, Rizzo AJ, Myers KM, Davis C, Zhang R, Esopi DM, Raabe EH, Eberhart CG, Heaphy CM, Meeker AK. ATRX loss induces multiple hallmarks of the alternative lengthening of telomeres (ALT) phenotype in human glioma cell lines in a cell line-specific manner. PLoS One 2018; 13:e0204159. [PMID: 30226859 PMCID: PMC6143253 DOI: 10.1371/journal.pone.0204159] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 09/03/2018] [Indexed: 12/05/2022] Open
Abstract
Cancers must maintain their telomeres at lengths sufficient for cell survival. In several cancer subtypes, a recombination-like mechanism termed alternative lengthening of telomeres (ALT), is frequently used for telomere length maintenance. Cancers utilizing ALT often have lost functional ATRX, a chromatin remodeling protein, through mutation or deletion, thereby strongly implicating ATRX as an ALT suppressor. Herein, we have generated functional ATRX knockouts in four telomerase-positive, ALT-negative human glioma cell lines: MOG-G-UVW, SF188, U-251 and UW479. After loss of ATRX, two of the four cell lines (U-251 and UW479) show multiple characteristics of ALT-positive cells, including ultrabright telomeric DNA foci, ALT-associated PML bodies, and c-circles. However, telomerase activity and overall telomere length heterogeneity are unaffected after ATRX loss, regardless of cellular context. The two cell lines that showed ALT hallmarks after complete ATRX loss also did so upon ATRX depletion via shRNA-mediated knockdown. These results suggest that other genomic or epigenetic events, in addition to ATRX loss, are necessary for the induction of ALT in human cancer.
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Affiliation(s)
| | - Ming Yuan
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Mindy K. Graham
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Anthony J. Rizzo
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Kaylar M. Myers
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Christine Davis
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Rebecca Zhang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - David M. Esopi
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Eric H. Raabe
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- Department of Pediatric Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Charles G. Eberhart
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Christopher M. Heaphy
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Alan K. Meeker
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
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5
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Lai S, Heaphy CM, Rizzo AJ, Celentano DD, Gerstenblith G, Li J, Moore RD, Treisman G, Chen S, Foster P, Kickler T, Lai H. Cocaine use may induce telomere shortening in individuals with HIV infection. Prog Neuropsychopharmacol Biol Psychiatry 2018; 84:11-17. [PMID: 29410247 PMCID: PMC5880737 DOI: 10.1016/j.pnpbp.2018.01.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/14/2018] [Accepted: 01/22/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND Although cocaine use may induce/accelerate HIV-associated comorbidities in HIV-infected individuals on antiretroviral therapy (ART), and that HIV itself may accelerate aging, the issue of whether cocaine use plays a role in HIV-associated aging in HIV-infected cocaine users has not been reported. The goals of this study were (1) to explore factor(s) associated with peripheral blood leukocyte telomere length, a marker of cellular replicative history, and telomere shortening in HIV-infected individuals, and (2) to assess whether cocaine use plays a role in accelerating telomere shortening in cocaine users with HIV infection. METHODS Between June 2010 and December 2016, 147 HIV-infected participants in Baltimore, Maryland, were enrolled in a cross-sectional study investigating factor(s) associated with telomere length. Of these 147, 93 participated in a follow-up study to examine factor(s) associated with telomere shortening. Robust regression model was used to analyze cross-sectional data and the generalized estimating equation approach was used to analyze follow-up data. RESULTS Cross-sectional analyses demonstrated that (1) both daily alcohol consumption and use of non-nucleoside reverse transcriptase inhibitors (NNRTIs) were independently associated with telomere length, and cocaine use modified the associations of daily alcohol use and NNRTI use with telomere length. Longitudinal analyses suggested that both daily alcohol consumption and duration of NNRTI use were independently associated with telomere shortening, and (2) cocaine use induced/accelerated telomere shortening in HIV-infected individuals. CONCLUSIONS Our findings suggest that cocaine use may promote premature aging in HIV-infected individuals who are on ART. Our results emphasize the importance of cocaine abstinence/reduced use, which may retard HIV-associated premature aging.
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Affiliation(s)
- Shenghan Lai
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Psychiatry, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Radiology, Johns Hopkins School of Medicine, Baltimore, MD, USA.
| | | | - Anthony J. Rizzo
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - David D. Celentano
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Gary Gerstenblith
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Ji Li
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Richard D. Moore
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Glenn Treisman
- Department of Psychiatry, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Shaoguang Chen
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Parker Foster
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Thomas Kickler
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Hong Lai
- Department of Radiology, Johns Hopkins School of Medicine, Baltimore, MD, USA
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6
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Diplas BH, He X, Brosnan-Cashman JA, Liu H, Chen LH, Wang Z, Moure CJ, Killela PJ, Loriaux DB, Lipp ES, Greer PK, Yang R, Rizzo AJ, Rodriguez FJ, Friedman AH, Friedman HS, Wang S, He Y, McLendon RE, Bigner DD, Jiao Y, Waitkus MS, Meeker AK, Yan H. The genomic landscape of TERT promoter wildtype-IDH wildtype glioblastoma. Nat Commun 2018; 9:2087. [PMID: 29802247 PMCID: PMC5970234 DOI: 10.1038/s41467-018-04448-6] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/26/2018] [Indexed: 12/26/2022] Open
Abstract
The majority of glioblastomas can be classified into molecular subgroups based on mutations in the TERT promoter (TERTp) and isocitrate dehydrogenase 1 or 2 (IDH). These molecular subgroups utilize distinct genetic mechanisms of telomere maintenance, either TERTp mutation leading to telomerase activation or ATRX-mutation leading to an alternative lengthening of telomeres phenotype (ALT). However, about 20% of glioblastomas lack alterations in TERTp and IDH. These tumors, designated TERTpWT-IDHWT glioblastomas, do not have well-established genetic biomarkers or defined mechanisms of telomere maintenance. Here we report the genetic landscape of TERTpWT-IDHWT glioblastoma and identify SMARCAL1 inactivating mutations as a novel genetic mechanism of ALT. Furthermore, we identify a novel mechanism of telomerase activation in glioblastomas that occurs via chromosomal rearrangements upstream of TERT. Collectively, our findings define novel molecular subgroups of glioblastoma, including a telomerase-positive subgroup driven by TERT-structural rearrangements (IDHWT-TERTSV), and an ALT-positive subgroup (IDHWT-ALT) with mutations in ATRX or SMARCAL1. Glioblastoma can be classified based on IDH and TERT promoter mutations, but ~20% of glioblastoma do not have these mutations (TERTpWT-IDHWT glioblastoma). Here, the authors present a genetic landscape of TERTpWT-IDHWT glioblastoma, identifying a telomerase-positive subgroup driven by TERT-structural rearrangements and an ALT-positive subgroup with mutations in ATRX or SMARCAL1.
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Affiliation(s)
- Bill H Diplas
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA
| | - Xujun He
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA.,Key Laboratory of Gastroenterology of Zhejiang Province, Zhejiang Provincial People's Hospital, Hangzhou Medical College, Hangzhou, 310014, China
| | - Jacqueline A Brosnan-Cashman
- Department of Pathology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Johns Hopkins University School of Medicine, Baltimore, 21231, MD, USA
| | - Heng Liu
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA
| | - Lee H Chen
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA
| | - Zhaohui Wang
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA
| | - Casey J Moure
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA
| | - Patrick J Killela
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA
| | - Daniel B Loriaux
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA
| | - Eric S Lipp
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA
| | - Paula K Greer
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA
| | - Rui Yang
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA
| | - Anthony J Rizzo
- Department of Pathology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Johns Hopkins University School of Medicine, Baltimore, 21231, MD, USA
| | - Fausto J Rodriguez
- Department of Pathology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Johns Hopkins University School of Medicine, Baltimore, 21231, MD, USA
| | - Allan H Friedman
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Neurosurgery, Duke University Medical Center, Durham, 27710, NC, USA
| | - Henry S Friedman
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA
| | - Sizhen Wang
- Genetron Health (Beijing) Co. Ltd, Beijing, 102208, China
| | - Yiping He
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA
| | - Roger E McLendon
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA
| | - Darell D Bigner
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA.,Department of Neurosurgery, Duke University Medical Center, Durham, 27710, NC, USA
| | - Yuchen Jiao
- State Key Laboratory of Molecular Oncology, Laboratory of Cell and Molecular Biology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
| | - Matthew S Waitkus
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA. .,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA.
| | - Alan K Meeker
- Department of Pathology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Johns Hopkins University School of Medicine, Baltimore, 21231, MD, USA.
| | - Hai Yan
- The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Durham, 27710, NC, USA. .,Department of Pathology, Duke University Medical Center, Durham, 27710, NC, USA.
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7
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Rizzo AJ, Brosnan-Cashman JA, Graham MK, Meeker AK, Heaphy CM. Abstract 3464: CRISPR-mediated inactivation of ATRX and DAXX in pancreatic neuroendocrine tumor cell lines. Cancer Res 2017. [DOI: 10.1158/1538-7445.am2017-3464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Cancer cells must find a way to subvert replicative senescence in order to achieve cellular immortality. While most malignancies (> 90 %) overcome this critical barrier by reactivating the telomerase enzyme, a telomere-specific reverse transcriptase; other cancers (5 - 10 %) utilize a telomerase-independent pathway of telomere maintenance, referred to as Alternative Lengthening of Telomeres (ALT). ALT is thought to utilize homologous recombination and DNA damage repair (DDR) machinery to maintain the chromosome ends. Importantly, this mechanism appears to be cancer-specific and dependent on alterations in chromatin dynamics at the telomeres, almost invariably facilitated by inactivating mutations in the genes, ATRX and DAXX. The protein products of these genes are responsible for the deposition of histone variant H3.3 at repetitive regions of DNA (e.g. telomeres) and when altered, the affected cells tend to exhibit the ALT phenotype. Pancreatic neuroendocrine tumors (PanNETs) are an example of a tumor type that often employs the ALT pathway with coincident somatic mutations in either the ATRX or DAXX genes. PanNETs are the second most common pancreatic malignancy, with only 40% of affected patients surviving past 10 years. Recently, we and others have demonstrated that in primary PanNETs, ALT is an independent prognostic marker, associated with aggressive clinicopathologic behavior and reduced recurrence-free survival. In addition, current data suggest that ALT-positive cancer cells are sensitive to inhibition of the DNA-damage mediator, ATR. In light of these findings, there seems to be an opportunity to develop ALT specific therapeutic modalities that would have considerable clinical utility. Models of ALT-positive PanNET pathology are needed to further progress in this direction, unfortunately, there are currently no ALT-positive PanNET cell lines. BON1 and QGP1, the two well characterized PanNET cell lines that are available, are both ALT-negative and retain expression of telomerase, ATRX, and DAXX. In an attempt recapitulate the ALT phenotype in a PanNET cell line, we derived a panel of isogenic cell lines from both BON1 and QGP1 by utilizing the CRISPR-Cas9 nickase system to target ATRX and DAXX. In both cell lines, we have successfully established 5 independent subclones with inactivating mutations in either ATRX or DAXX, validated by Sanger sequencing. We are currently characterizing these novel subclones for the hallmarks of ALT, including the presence of ultrabright telomeric foci, dramatic telomere length heterogeneity, and the presence of extrachromosomal telomeric DNA (e.g. c-circles). Once validated, we plan to investigate whether these ATRX or DAXX-deficient subclones are more sensitive to DDR pathway inhibition (i.e. ATR, ATM, CHK1 and CHK2) pharmacologically or with RNA interference in order to identify new therapeutic strategies for PanNETs.
Citation Format: Anthony J. Rizzo, Jacqueline A. Brosnan-Cashman, Mindy K. Graham, Alan K. Meeker, Christopher M. Heaphy. CRISPR-mediated inactivation of ATRX and DAXX in pancreatic neuroendocrine tumor cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3464. doi:10.1158/1538-7445.AM2017-3464
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Affiliation(s)
| | | | | | - Alan K. Meeker
- Johns Hopkins University School of Medicine, Baltimore, MD
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Brosnan-Cashman JA, Rizzo AJ, Goger E, Myers KM, Zarinshenas R, Davis C, Yuan M, Rakheja D, Raabe EH, Eberhart CG, Heaphy CM, Meeker AK. Abstract 3466: ALT-positive pediatric high grade glioma cells display chemosensitivity to ATR pathway inhibition. Cancer Res 2017. [DOI: 10.1158/1538-7445.am2017-3466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Overcoming the end-replication problem is a major hurdle for cancer cells due to progressive telomere shortening that results from excessive cell division during tumorigenesis. While most cancers activate telomerase to maintain their telomere length, about five percent of cancers use a telomerase-independent telomere maintenance mechanism, termed alternative lengthening of telomeres (ALT). Despite its low overall frequency in cancer, ALT is enriched in several cancer subtypes, including pediatric high grade glioma (HGG). Previous work in our laboratory suggests that nearly half of pediatric HGG utilize the ALT mechanism. To date, therapeutic options are largely ineffective for children with HGG, reflected in the dismal five-year survival rate, which is less than 33 percent. Our goal is to better harness ALT as a clinical marker in pediatric HGG, specifically by identifying drugs that target ALT-positive cancers. In order to study ALT in this context, we obtained and characterized a panel of six pediatric HGG cell lines. Two of the six cell lines in this panel display hallmarks of the ALT pathway. To assess the potential of ALT as a therapeutic biomarker in pediatric HGG, we measured cell viability in the presence of inhibitors, stratifying our analysis by ALT status. ALT is predicted to occur via a homologous-recombination-based mechanism. As such, we focused our attention on inhibitors of the DNA damage response, as well as agents that induce DNA damage. Treatment with inhibitors of DNA-PK, RAD51, and MRE11 did not result in significant differences in cell viability when stratified by ALT status, nor did treatment with temozolomide or hydroxyurea. However, inhibitors of ATR (VE-821, VE-822/VX-970, and AZD-6738) and CHK1 (MK-8776) led to significantly greater reductions in cell viability in ALT-positive cells. In order to further our understanding of the mechanism through which ATR inhibition preferentially targets ALT-positive cell lines, we examined the effect of these inhibitors on ALT-specific properties, such as the presence of ultrabright telomeric foci and extrachromosomal telomeric DNA (c-circles). Preliminary results indicate that ATR inhibition does not diminish these ALT-associated properties and, therefore, the differential sensitivity to these agents is unlikely to be due to directly blocking the ALT telomere maintenance mechanism. Continued study of the effect of ATR/CHK1 inhibition on ALT-positive cells will yield further insight into the mechanism of ALT-specific toxicity. Overall, we have identified ATR/CHK1 as a promising pathway to target for ALT-positive pediatric HGG. Our goal is to better understand the relationship between ATR/CHK1 signaling and ALT in order to effectively translate this observation to the clinic, both for pediatric HGG and for other ALT-positive cancers.
Citation Format: Jacqueline A. Brosnan-Cashman, Anthony J. Rizzo, Ezgi Goger, Kaylar M. Myers, Reza Zarinshenas, Christine Davis, Ming Yuan, Dinesh Rakheja, Eric H. Raabe, Charles G. Eberhart, Christopher M. Heaphy, Alan K. Meeker. ALT-positive pediatric high grade glioma cells display chemosensitivity to ATR pathway inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3466. doi:10.1158/1538-7445.AM2017-3466
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Affiliation(s)
| | | | - Ezgi Goger
- 1Johns Hopkins University School of Medicine, Baltimore, MD
| | | | | | | | - Ming Yuan
- 1Johns Hopkins University School of Medicine, Baltimore, MD
| | - Dinesh Rakheja
- 2University of Texas Southwestern Medical Center, Dallas, TX
| | - Eric H. Raabe
- 1Johns Hopkins University School of Medicine, Baltimore, MD
| | | | | | - Alan K. Meeker
- 1Johns Hopkins University School of Medicine, Baltimore, MD
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Rizzo AJ, Haller JO, Mulvihill DM, Cohen HL, Da Silva MG. Calcification of the ductus venosus: a cause of right upper quadrant calcification in the newborn. Radiology 1989; 173:89-90. [PMID: 2675191 DOI: 10.1148/radiology.173.1.2675191] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The authors report three cases of ductus venosus calcification as an additional cause of vascular liver calcification in the newborn. All three infants had umbilical venous catheters. The calcification may be caused by extravasated fluids given through the catheter or by local trauma due to catheter insertion. An obliquely oriented, paravertebral "tram-track" calcification in the right upper quadrant, particularly in a premature infant with a history of umbilical venous catheterization, should suggest the diagnosis of calcified ductus venosus.
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Affiliation(s)
- A J Rizzo
- Department of Radiology, SUNY Downstate Medical Center, Brooklyn 11203
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van Houten M, Rizzo AJ, Goltzman D, Posner BI. Brain receptors for blood-borne calcitonin in rats: circumventricular localization and vasopressin-resistant deficiency in hereditary diabetes insipidus. Endocrinology 1982; 111:1704-10. [PMID: 6290196 DOI: 10.1210/endo-111-5-1704] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Specific binding sites for blood-borne calcitonin were localized by means of quantitative radioautography to the circumventricular organs of the rat brain. By this method, using normal Long-Evans rats as controls, specific binding of blood-borne calcitonin in the median eminence region of the hypothalamus was reduced by one-third in homozygous Brattleboro rats, which are genetically deficient in vasopressin. Competitive binding analysis in vitro of the hypothalami from these animals confirmed the binding deficit in homozygous rats, and Scatchard analysis suggested a reduction in the number of binding sites. In homozygous rats daily vasopressin replacement therapy restored normal water balance but did not normalize the hypothalamic calcitonin binding deficit. These studies delineate for the first time specific sites within the central nervous system which could serve to mediate direct actions of blood-borne calcitonin on brain function. The deficit in the Brattleboro rat may provide a model for further investigation of the role of calcitonin within selective regions of the central nervous system.
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van Houten M, Rizzo AJ, Goltzman D, Posner BI. The hypothalamic median eminence of the homozygous Brattleboro rat is deficient in calcitonin-specific binding sites. Ann N Y Acad Sci 1982; 394:650-4. [PMID: 6295239 DOI: 10.1111/j.1749-6632.1982.tb37483.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Abstract
Cordycepin (3′-deoxyadenosine), at a dose of 10 mg/kg, inhibits the accumulation of ribosomes in rat liver cytoplasm within 2.5 h of administration. This effect is not due to an inhibition of RNA synthesis per se but rather to the premature termination of the transcription of the 45 S ribosomal precursor in the presence of the analogue. The nucleoside analogue also inhibits the corticosteroid-mediated induction of tyrosine transaminase and general protein synthesis. The latter results are consistent with the current theory that cordycepin inhibits the formation of polyadenylic acid which is involved in the nuclear processing and/or nucleocytoplasmic transport of messenger RNA.
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Rizzo AJ, Webb TE. Concurrent changes in the concentration of monomeric ribosomes and the rate of ribosome synthesis in rat liver. Biochim Biophys Acta 1968; 169:163-74. [PMID: 5727129 DOI: 10.1016/0005-2787(68)90017-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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