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Bhattarai S, Hakkim FL, Day CA, Grigore F, Langfald A, Entin I, Hinchcliffe EH, Robinson JP. H3F3A K27M Mutations Drives a Repressive Transcriptome by Modulating Chromatin Accessibility, Independent of H3K27me3 in Diffuse Midline Glioma. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.16.594522. [PMID: 38798502 PMCID: PMC11118475 DOI: 10.1101/2024.05.16.594522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Background Heterozygous histone H3.3K27M mutation is a primary oncogenic driver of Diffuse Midline Glioma (DMG). H3.3K27M inhibits the Polycomb Repressive Complex 2 (PRC2) methyltransferase complex, leading to a global reduction and redistributing of the repressive H3 lysine 27 tri-methylation. This rewiring of the epigenome is thought to promote gliomagenesis. Methods We established novel, isogenic DMG patient-derived cell lines that have been CRISPR-Cas9 edited to H3.3 WT or H3.3K27M alone and in combination with EZH2 and EZH1 co-deletion, inactivating PRC2 methyltransferase activity of PRC2 and eliminating H3K27me3. Results RNA-seq and ATAC-seq analysis of these cells revealed that K27M has a novel epigenetic effect that appears entirely independent of its effects on PRC2 function. While the loss of the PRC2 complex led to a systemic induction of gene expression (including HOX gene clusters) and upregulation of biological pathways, K27M led to a balanced gene deregulation but having an overall repressive effect on the biological pathways. Importantly, the genes uniquely deregulated by the K27M mutation, independent of methylation loss, are closely associated with changes in chromatin accessibility, with upregulated genes becoming more accessible. Notably, the PRC2- independent function of K27M appears necessary for tumorigenesis as xenografts of our H3.3K27M/EZH1/2 WT cells developed into tumors, while H3.3/EZH1/2 KO cells did not. Conclusion We demonstrate that K27M mutation alters chromatin accessibility and uniquely deregulates genes, independent of K27 methylation. We further show the mutation's role in altering biological pathways and its necessity for tumor development. Key Points We revealed genes regulated by H3.3K27M mutation and PRC2 in DMG.H3.3K27M mutation alters chromosome accessibility independent of H3K27me3.PRC2-independent effects of K27M mutation are crucial for tumor development. Importance of the Study This study is the first to demonstrate that H3F3A K27M mutations drive a repressive transcriptome by modulating chromatin accessibility independently of H3K27 trimethylation in Diffuse Midline Glioma (DMG). By isolating the effects of H3.3 K27me3 loss from those of the K27M mutation, we identified common and unique genes and pathways affected by each. We found that genes uniquely deregulated by K27M showed increased chromatin accessibility and upregulated gene expression, unlike other gene subsets affected by PRC2 knockout. Importantly, we determined the PRC2-independent function of K27M is also essential for tumorigenesis, as xenografts of H3.3 K27M/PRC2 WT cell lines formed tumors, while H3.3WT/PRC2 WT and K27M/PRC2 knockout cells did not. This research builds upon and advances prior studies, such as those identifying EZH2 as a therapeutic target in H3.3K27M DMGs, by revealing critical new pathways for gliomagenesis. The translational significance lies in identifying novel therapeutic targets against this aggressive pediatric cancer.
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Saratsis AM, Knowles T, Petrovic A, Nazarian J. H3K27M mutant glioma: Disease definition and biological underpinnings. Neuro Oncol 2024; 26:S92-S100. [PMID: 37818718 PMCID: PMC11066930 DOI: 10.1093/neuonc/noad164] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Indexed: 10/12/2023] Open
Abstract
High-grade glioma (HGG) is the most common cause of cancer death in children and the most common primary central nervous system tumor in adults. While pediatric HGG was once thought to be biologically similar to the adult form of disease, research has shown these malignancies to be significantly molecularly distinct, necessitating distinct approaches to their clinical management. However, emerging data have shown shared molecular events in pediatric and adult HGG including the histone H3K27M mutation. This somatic missense mutation occurs in genes encoding one of two isoforms of the Histone H3 protein, H3F3A (H3.3), or HIST1H3B (H3.1), and is detected in up to 80% of pediatric diffuse midline gliomas and in up to 60% of adult diffuse gliomas. Importantly, the H3K27M mutation is associated with poorer overall survival and response to therapy compared to patients with H3 wild-type tumors. Here, we review the clinical features and biological underpinnings of pediatric and adult H3K27M mutant glioma, offering a groundwork for understanding current research and clinical approaches for the care of patients suffering with this challenging disease.
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Affiliation(s)
| | | | - Antonela Petrovic
- DMG Research Center, Department of Oncology, University Children’s Hospital, University of Zürich, Zürich, Switzerland
| | - Javad Nazarian
- Research Center for Genetic Medicine, Children’s National Health System, Washington, District of Columbia, USA
- Brain Tumor Institute, Children’s National Health System, Washington, District of Columbia, USA
- DMG Research Center, Department of Pediatrics, University Children’s Hospital, University of Zurich, Zürich, Switzerland
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Sarkar S, Deyoung T, Ressler H, Chandler W. Brain Tumors: Development, Drug Resistance, and Sensitization - An Epigenetic Approach. Epigenetics 2023; 18:2237761. [PMID: 37499114 PMCID: PMC10376921 DOI: 10.1080/15592294.2023.2237761] [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: 02/05/2023] [Revised: 06/26/2023] [Accepted: 07/11/2023] [Indexed: 07/29/2023] Open
Abstract
In this article, we describe contrasting developmental aspects of paediatric and adult brain tumours. We hypothesize that the formation of cancer progenitor cells, for both paediatric and adult, could be due to epigenetic events. However, the progression of adult brain tumours selectively involves more mutations compared to paediatric tumours. We further discuss epigenetic switches, comprising both histone modifications and DNA methylation, and how they can differentially regulate transcription and expression of oncogenes and tumour suppressor genes. Next, we summarize the currently available therapies for both types of brain tumours, explaining the merits and failures leading to drug resistance. We analyse different mechanisms of drug resistance and the role of epigenetics in this process. We then provide a rationale for combination therapy, which includes epigenetic drugs. In the end, we postulate a concept which describes how a combination therapy could be initiated. The timing, doses, and order of individual drug regimens will depend on the individual case. This type of combination therapy will be part of a personalized medicine which will differ from patient to patient.
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Affiliation(s)
- Sibaji Sarkar
- Division of Biotechnology, Quincy College, Quincy, MA, USA
- Division of Biology, STEM, MBC College, Wellesley, MA, USA
- Division of Biology, STEM, RC College Boston, Boston, MA, USA
| | - Tara Deyoung
- Division of Biotechnology, Quincy College, Quincy, MA, USA
| | - Hope Ressler
- Division of Biology, STEM, MBC College, Wellesley, MA, USA
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Paniri A, Hosseini MM, Amjadi-Moheb F, Tabaripour R, Soleimani E, Langroudi MP, Zafari P, Akhavan-Niaki H. The epigenetics orchestra of Notch signaling: a symphony for cancer therapy. Epigenomics 2023; 15:1337-1358. [PMID: 38112013 DOI: 10.2217/epi-2023-0270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023] Open
Abstract
The aberrant regulation of the Notch signaling pathway, which is a fundamental developmental pathway, has been implicated in a wide range of human cancers. The Notch pathway can be activated by both canonical and noncanonical Notch ligands, and its role can switch between acting as an oncogene or a tumor suppressor depending on the context. Epigenetic modifications have the potential to modulate Notch and its ligands, thereby influencing Notch signal transduction. Consequently, the utilization of epigenetic regulatory mechanisms may present novel therapeutic opportunities for both single and combined therapeutics targeted at the Notch signaling pathway. This review offers insights into the mechanisms governing the regulation of Notch signaling and explores their therapeutic potential.
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Affiliation(s)
- Alireza Paniri
- Department of Genetics, Faculty of Medicine, Babol University of Medical Sciences, Babol, 4717647745,Iran
- Zoonoses Research Center, Pasteur Institute of Iran, 4619332976, Amol, Iran
| | | | - Fatemeh Amjadi-Moheb
- Department of Genetics, Faculty of Medicine, Babol University of Medical Sciences, Babol, 4717647745,Iran
| | - Reza Tabaripour
- Department of Cellular and Molecular Biology, Babol Branch, Islamic Azad University, Babol, 4747137381, Iran
| | - Elnaz Soleimani
- Department of Genetics, Faculty of Medicine, Babol University of Medical Sciences, Babol, 4717647745,Iran
| | | | - Parisa Zafari
- Ramsar Campus, Mazandaran University of Medical Sciences, Ramsar, 4691786953, Iran
| | - Haleh Akhavan-Niaki
- Department of Genetics, Faculty of Medicine, Babol University of Medical Sciences, Babol, 4717647745,Iran
- Zoonoses Research Center, Pasteur Institute of Iran, 4619332976, Amol, Iran
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Di Liegro CM, Schiera G, Schirò G, Di Liegro I. Involvement of the H3.3 Histone Variant in the Epigenetic Regulation of Gene Expression in the Nervous System, in Both Physiological and Pathological Conditions. Int J Mol Sci 2023; 24:11028. [PMID: 37446205 DOI: 10.3390/ijms241311028] [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: 05/15/2023] [Revised: 06/19/2023] [Accepted: 07/01/2023] [Indexed: 07/15/2023] Open
Abstract
All the cells of an organism contain the same genome. However, each cell expresses only a minor fraction of its potential and, in particular, the genes encoding the proteins necessary for basal metabolism and the proteins responsible for its specific phenotype. The ability to use only the right and necessary genes involved in specific functions depends on the structural organization of the nuclear chromatin, which in turn depends on the epigenetic history of each cell, which is stored in the form of a collection of DNA and protein modifications. Among these modifications, DNA methylation and many kinds of post-translational modifications of histones play a key role in organizing the complex indexing of usable genes. In addition, non-canonical histone proteins (also known as histone variants), the synthesis of which is not directly linked with DNA replication, are used to mark specific regions of the genome. Here, we will discuss the role of the H3.3 histone variant, with particular attention to its loading into chromatin in the mammalian nervous system, both in physiological and pathological conditions. Indeed, chromatin modifications that mark cell memory seem to be of special importance for the cells involved in the complex processes of learning and memory.
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Affiliation(s)
- Carlo Maria Di Liegro
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, 90128 Palermo, Italy
| | - Gabriella Schiera
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, 90128 Palermo, Italy
| | - Giuseppe Schirò
- Department of Biomedicine, Neurosciences and Advanced Diagnostics (Bi.N.D.), University of Palermo, 90127 Palermo, Italy
| | - Italia Di Liegro
- Department of Biomedicine, Neurosciences and Advanced Diagnostics (Bi.N.D.), University of Palermo, 90127 Palermo, Italy
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Knowles T, Huang T, Qi J, An S, Burket N, Cooper S, Nazarian J, Saratsis AM. LIN28B and Let-7 in Diffuse Midline Glioma: A Review. Cancers (Basel) 2023; 15:3241. [PMID: 37370851 DOI: 10.3390/cancers15123241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/12/2023] [Accepted: 06/17/2023] [Indexed: 06/29/2023] Open
Abstract
Diffuse midline glioma (DMG) is the most lethal of all childhood cancers. DMGs are driven by histone-tail-mutation-mediated epigenetic dysregulation and partner mutations in genes controlling proliferation and migration. One result of this epigenetic and genetic landscape is the overexpression of LIN28B RNA binding protein. In other systems, LIN28B has been shown to prevent let-7 microRNA biogenesis; however, let-7, when available, faithfully suppresses tumorigenic pathways and induces cellular maturation by preventing the translation of numerous oncogenes. Here, we review the current literature on LIN28A/B and the let-7 family and describe their role in gliomagenesis. Future research is then recommended, with a focus on the mechanisms of LIN28B overexpression and localization in DMG.
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Affiliation(s)
- Truman Knowles
- W.M. Keck Science Department, Scripps, Pitzer, and Claremont McKenna Colleges, Claremont, CA 91711, USA
| | - Tina Huang
- Department of Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jin Qi
- Department of Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Shejuan An
- Department of Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Noah Burket
- Department of Neurosurgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Scott Cooper
- Department of Neurosurgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Javad Nazarian
- Department of Pediatrics, Children's National Hospital, Washington, DC 20010, USA
- Department of Pediatrics, Zurich Children's Hospital, 8032 Zurich, Switzerland
| | - Amanda M Saratsis
- Department of Neurosurgery, Lutheran General Hospital, Park Ridge, IL 60068, USA
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Park J, Chung C. Epigenetic and Metabolic Changes in Diffuse Intrinsic Pontine Glioma. Brain Tumor Res Treat 2023; 11:86-93. [PMID: 37151150 PMCID: PMC10172016 DOI: 10.14791/btrt.2023.0011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/07/2023] [Accepted: 04/13/2023] [Indexed: 05/09/2023] Open
Abstract
Diffuse midline glioma (DMG), hitherto known as diffuse intrinsic pontine glioma (DIPG), is a rare and aggressive form of brain cancer that primarily affects children. Although the exact cause of DMG/DIPG is not known, a large proportion of DMG/DIPG tumors harbor mutations in the gene encoding the histone H3 protein, specifically the H3K27M mutation. This mutation decreases the level of H3K27me3, a histone modification that plays a vital role in regulating gene expression through epigenetic regulation. The mutation also alters the function of polycomb repressive complex 2 (PRC2), thereby preventing the repression of genes associated with cancer development. The decrease in H3K27me3 caused by the histone H3 mutation is accompanied by an increase in the level of H3K27ac, a post-translational modification related to active transcription. Dysregulation of histone modification markedly affects gene expression, contributing to cancer development and progression by promoting uncontrolled cell proliferation, tumor growth, and metabolism. DMG/DIPG alters the metabolism of methionine and the tricarboxylic acid cycle, as well as glucose and glutamine uptake. The role of epigenetic and metabolic changes in the development of DMG/DIPG has been studied extensively, and understanding these changes is critical to developing therapies targeting these pathways. Studies are currently underway to identify new therapeutic targets for DMG/DIPG, which may lead to the development of effective treatments for this devastating disease.
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Affiliation(s)
- Jiyoon Park
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
- New Biology Research Center (NBRC), Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Chan Chung
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
- New Biology Research Center (NBRC), Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea.
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Zhuang HH, Qu Q, Teng XQ, Dai YH, Qu J. Superenhancers as master gene regulators and novel therapeutic targets in brain tumors. Exp Mol Med 2023; 55:290-303. [PMID: 36720920 PMCID: PMC9981748 DOI: 10.1038/s12276-023-00934-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 11/27/2022] [Accepted: 12/04/2022] [Indexed: 02/02/2023] Open
Abstract
Transcriptional deregulation, a cancer cell hallmark, is driven by epigenetic abnormalities in the majority of brain tumors, including adult glioblastoma and pediatric brain tumors. Epigenetic abnormalities can activate epigenetic regulatory elements to regulate the expression of oncogenes. Superenhancers (SEs), identified as novel epigenetic regulatory elements, are clusters of enhancers with cell-type specificity that can drive the aberrant transcription of oncogenes and promote tumor initiation and progression. As gene regulators, SEs are involved in tumorigenesis in a variety of tumors, including brain tumors. SEs are susceptible to inhibition by their key components, such as bromodomain protein 4 and cyclin-dependent kinase 7, providing new opportunities for antitumor therapy. In this review, we summarized the characteristics and identification, unique organizational structures, and activation mechanisms of SEs in tumors, as well as the clinical applications related to SEs in tumor therapy and prognostication. Based on a review of the literature, we discussed the relationship between SEs and different brain tumors and potential therapeutic targets, focusing on glioblastoma.
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Affiliation(s)
- Hai-Hui Zhuang
- Department of Pharmacy, the Second Xiangya Hospital, Central South University, Institute of Clinical Pharmacy, Central South University, Changsha, 410011, PR China
| | - Qiang Qu
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, 410007, PR China.,Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410007, PR China
| | - Xin-Qi Teng
- Department of Pharmacy, the Second Xiangya Hospital, Central South University, Institute of Clinical Pharmacy, Central South University, Changsha, 410011, PR China
| | - Ying-Huan Dai
- Department of Pathology, the Second Xiangya Hospital, Central South University, Changsha, 410011, PR China
| | - Jian Qu
- Department of Pharmacy, the Second Xiangya Hospital, Central South University, Institute of Clinical Pharmacy, Central South University, Changsha, 410011, PR China.
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Grigore FN, Yang SJ, Chen CC, Koga T. Pioneering models of pediatric brain tumors. Neoplasia 2023; 36:100859. [PMID: 36599191 PMCID: PMC9823239 DOI: 10.1016/j.neo.2022.100859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 11/16/2022] [Accepted: 11/28/2022] [Indexed: 01/04/2023]
Abstract
Among children and adolescents in the United States (0 to 19 years old), brain and other central nervous system tumors are the second most common types of cancers, surpassed in incidence only by leukemias. Despite significant progress in the diagnosis and treatment modalities, brain cancer remains the leading cause of death in the pediatric population. There is an obvious unfulfilled need to streamline the therapeutic strategies and improve survival for these patients. For that purpose, preclinical models play a pivotal role. Numerous models are currently used in pediatric brain tumor research, including genetically engineered mouse models, patient-derived xenografts and cell lines, and newer models that utilize novel technologies such as genome engineering and organoids. Furthermore, extensive studies by the Children's Brain Tumor Network (CBTN) researchers and others have revealed multiomic landscapes of variable pediatric brain tumors. Combined with such integrative data, these novel technologies have enabled numerous applicable models. Genome engineering, including CRISPR/Cas9, expanded the flexibility of modeling. Models generated through genome engineering enabled studying particular genetic alterations in clean isogenic backgrounds, facilitating the dissection of functional mechanisms of those mutations in tumor biology. Organoids have been applied to study tumor-to-tumor-microenvironment interactions and to address developmental aspects of tumorigenesis, which is essential in some pediatric brain tumors. Other modalities, such as humanized mouse models, could potentially be applied to pediatric brain tumors. In addition to current valuable models, such novel models are anticipated to expedite functional tumor biology study and establish effective therapeutics for pediatric brain tumors.
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Affiliation(s)
- Florina-Nicoleta Grigore
- Department of Neurosurgery, University of Minnesota, MMC96, Room D-429, 420 Delaware St SE, Minneapolis, MN 55455, USA
| | - Serena Johanna Yang
- Department of Neurosurgery, University of Minnesota, MMC96, Room D-429, 420 Delaware St SE, Minneapolis, MN 55455, USA
| | - Clark C Chen
- Department of Neurosurgery, University of Minnesota, MMC96, Room D-429, 420 Delaware St SE, Minneapolis, MN 55455, USA
| | - Tomoyuki Koga
- Department of Neurosurgery, University of Minnesota, MMC96, Room D-429, 420 Delaware St SE, Minneapolis, MN 55455, USA.
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