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Karttunen K, Patel D, Sahu B. Transposable elements as drivers of dedifferentiation: Connections between enhancers in embryonic stem cells, placenta, and cancer. Bioessays 2024:e2400059. [PMID: 39073128 DOI: 10.1002/bies.202400059] [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: 03/14/2024] [Revised: 04/12/2024] [Indexed: 07/30/2024]
Abstract
Transposable elements (TEs) have emerged as important factors in establishing the cell type-specific gene regulatory networks and evolutionary novelty of embryonic and placental development. Recently, studies on the role of TEs and their dysregulation in cancers have shed light on the transcriptional, transpositional, and regulatory activity of TEs, revealing that the activation of developmental transcriptional programs by TEs may have a role in the dedifferentiation of cancer cells to the progenitor-like cell states. This essay reviews the recent evidence of the cis-regulatory TEs (henceforth crTE) in normal development and malignancy as well as the key transcription factors and regulatory pathways that are implicated in both cell states, and presents existing gaps remaining to be studied, limitations of current technologies, and therapeutic possibilities.
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Affiliation(s)
- Konsta Karttunen
- Applied Tumor Genomics Program, Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Divyesh Patel
- Applied Tumor Genomics Program, Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- iCAN Digital Precision Cancer Medicine Flagship, University of Helsinki, Helsinki, Finland
| | - Biswajyoti Sahu
- Applied Tumor Genomics Program, Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- iCAN Digital Precision Cancer Medicine Flagship, University of Helsinki, Helsinki, Finland
- Centre for Molecular Medicine Norway, University of Oslo, Oslo, Norway
- Department of Cancer Genetics, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
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Katoh H, Honda T. Roles of Human Endogenous Retroviruses and Endogenous Virus-Like Elements in Cancer Development and Innate Immunity. Biomolecules 2023; 13:1706. [PMID: 38136578 PMCID: PMC10741599 DOI: 10.3390/biom13121706] [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: 10/28/2023] [Revised: 11/18/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023] Open
Abstract
Human endogenous retroviruses (HERVs) are remnants of ancient retroviral infections in the host genome. Although mutations and silencing mechanisms impair their original role in viral replication, HERVs are believed to play roles in various biological processes. Long interspersed nuclear elements (LINEs) are non-LTR retrotransposons that have a lifecycle resembling that of retroviruses. Although LINE expression is typically silenced in somatic cells, it also contributes to various biological processes. The aberrant expression of HERVs and LINEs is closely associated with the development of cancer and/or immunological diseases, suggesting that they are integrated into various pathways related to the diseases. HERVs/LINEs control gene expression depending on the context as promoter/enhancer elements. Some RNAs and proteins derived from HERVs/LINEs have oncogenic potential, whereas others stimulate innate immunity. Non-retroviral endogenous viral elements (nrEVEs) are a novel type of virus-like element in the genome. nrEVEs may also be involved in host immunity. This article provides a current understanding of how these elements impact cellular physiology in cancer development and innate immunity, and provides perspectives for future studies.
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Affiliation(s)
- Hirokazu Katoh
- Department of Virology, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan;
| | - Tomoyuki Honda
- Department of Virology, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8558, Japan;
- Department of Virology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
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Pulver C, Grun D, Duc J, Sheppard S, Planet E, Coudray A, de Fondeville R, Pontis J, Trono D. Statistical learning quantifies transposable element-mediated cis-regulation. Genome Biol 2023; 24:258. [PMID: 37950299 PMCID: PMC10637000 DOI: 10.1186/s13059-023-03085-7] [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: 08/16/2022] [Accepted: 10/09/2023] [Indexed: 11/12/2023] Open
Abstract
BACKGROUND Transposable elements (TEs) have colonized the genomes of most metazoans, and many TE-embedded sequences function as cis-regulatory elements (CREs) for genes involved in a wide range of biological processes from early embryogenesis to innate immune responses. Because of their repetitive nature, TEs have the potential to form CRE platforms enabling the coordinated and genome-wide regulation of protein-coding genes by only a handful of trans-acting transcription factors (TFs). RESULTS Here, we directly test this hypothesis through mathematical modeling and demonstrate that differences in expression at protein-coding genes alone are sufficient to estimate the magnitude and significance of TE-contributed cis-regulatory activities, even in contexts where TE-derived transcription fails to do so. We leverage hundreds of overexpression experiments and estimate that, overall, gene expression is influenced by TE-embedded CREs situated within approximately 500 kb of promoters. Focusing on the cis-regulatory potential of TEs within the gene regulatory network of human embryonic stem cells, we find that pluripotency-specific and evolutionarily young TE subfamilies can be reactivated by TFs involved in post-implantation embryogenesis. Finally, we show that TE subfamilies can be split into truly regulatorily active versus inactive fractions based on additional information such as matched epigenomic data, observing that TF binding may better predict TE cis-regulatory activity than differences in histone marks. CONCLUSION Our results suggest that TE-embedded CREs contribute to gene regulation during and beyond gastrulation. On a methodological level, we provide a statistical tool that infers TE-dependent cis-regulation from RNA-seq data alone, thus facilitating the study of TEs in the next-generation sequencing era.
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Affiliation(s)
- Cyril Pulver
- School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Delphine Grun
- School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Julien Duc
- School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Shaoline Sheppard
- School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Evarist Planet
- School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Alexandre Coudray
- School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Raphaël de Fondeville
- Swiss Data Science Center, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015, Lausanne, Switzerland.
| | - Julien Pontis
- School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015, Lausanne, Switzerland.
- SOPHiA GENETICS SA, La Pièce 12, CH-1180, Rolle, Switzerland.
| | - Didier Trono
- School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015, Lausanne, Switzerland.
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Abstract
The human genome is organized into multiple structural layers, ranging from chromosome territories to progressively smaller substructures, such as topologically associating domains (TADs) and chromatin loops. These substructures, collectively referred to as long-range chromatin interactions (LRIs), have a significant role in regulating gene expression. TADs are regions of the genome that harbour groups of genes and regulatory elements that frequently interact with each other and are insulated from other regions, thereby preventing widespread uncontrolled DNA contacts. Chromatin loops formed within TADs through enhancer and promoter interactions are elastic, allowing transcriptional heterogeneity and stochasticity. Over the past decade, it has become evident that the 3D genome structure, also referred to as the chromatin architecture, is central to many transcriptional cellular decisions. In this Review, we delve into the intricate relationship between steroid receptors and LRIs, discussing how steroid receptors interact with and modulate these chromatin interactions. Genetic alterations in the many processes involved in organizing the nuclear architecture are often associated with the development of hormone-dependent cancers. A better understanding of the interplay between architectural proteins and hormone regulatory networks can ultimately be exploited to develop improved approaches for cancer treatment.
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Affiliation(s)
- Theophilus T Tettey
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Lorenzo Rinaldi
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Gordon L Hager
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD, USA.
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Osnato A, Pasque V, David L. The human embryo selection arena is associated with transposable element activity. PLoS Biol 2023; 21:e3002153. [PMID: 37348048 DOI: 10.1371/journal.pbio.3002153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023] Open
Abstract
Our current understanding of early human development is limited. A study in PLOS Biology found a previously undefined group of cells that diverges from the main lineages and undergo apoptosis through the activity of young transposable elements.
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Affiliation(s)
- Anna Osnato
- KU Leuven-University of Leuven, Department of Development and Regeneration, Leuven Stem Cell Institute, Leuven, Belgium
- KU Leuven Institute for Single Cell Omics (LISCO), Leuven, Belgium
| | - Vincent Pasque
- KU Leuven-University of Leuven, Department of Development and Regeneration, Leuven Stem Cell Institute, Leuven, Belgium
- KU Leuven Institute for Single Cell Omics (LISCO), Leuven, Belgium
| | - Laurent David
- Nantes Université, Inserm, CR2TI, Nantes, France
- Nantes Université, CHU Nantes, CNRS, Inserm, BioCore, Nantes, France
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Singh M, Kondrashkina AM, Widmann TJ, Cortes JL, Bansal V, Wang J, Römer C, Garcia-Canadas M, Garcia-Perez JL, Hurst LD, Izsvák Z. A new human embryonic cell type associated with activity of young transposable elements allows definition of the inner cell mass. PLoS Biol 2023; 21:e3002162. [PMID: 37339119 DOI: 10.1371/journal.pbio.3002162] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 05/12/2023] [Indexed: 06/22/2023] Open
Abstract
There remains much that we do not understand about the earliest stages of human development. On a gross level, there is evidence for apoptosis, but the nature of the affected cell types is unknown. Perhaps most importantly, the inner cell mass (ICM), from which the foetus is derived and hence of interest in reproductive health and regenerative medicine, has proven hard to define. Here, we provide a multi-method analysis of the early human embryo to resolve these issues. Single-cell analysis (on multiple independent datasets), supported by embryo visualisation, uncovers a common previously uncharacterised class of cells lacking commitment markers that segregates after embryonic gene activation (EGA) and shortly after undergo apoptosis. The discovery of this cell type allows us to clearly define their viable ontogenetic sisters, these being the cells of the ICM. While ICM is characterised by the activity of an Old non-transposing endogenous retrovirus (HERVH) that acts to suppress Young transposable elements, the new cell type, by contrast, expresses transpositionally competent Young elements and DNA-damage response genes. As the Young elements are RetroElements and the cells are excluded from the developmental process, we dub these REject cells. With these and ICM being characterised by differential mobile element activities, the human embryo may be a "selection arena" in which one group of cells selectively die, while other less damaged cells persist.
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Affiliation(s)
- Manvendra Singh
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin, Germany
- Max Planck Institute of Multidisciplinary Sciences, City Campus, Göttingen, Germany
| | | | - Thomas J Widmann
- GENYO, Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, Granada, Spain
| | - Jose L Cortes
- GENYO, Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, Granada, Spain
| | - Vikas Bansal
- German Center for Neurodegenerative Diseases, Tübingen, Germany
| | - Jichang Wang
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin, Germany
| | - Christine Römer
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin, Germany
| | - Marta Garcia-Canadas
- GENYO, Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, Granada, Spain
| | - Jose L Garcia-Perez
- GENYO, Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, Granada, Spain
- Institute of Genetics and Molecular Medicine (IGMM), University of Edinburgh, Crewe Road, Edinburgh, United Kingdom
| | - Laurence D Hurst
- The Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - Zsuzsanna Izsvák
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin, Germany
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Agoni L. Alternative and aberrant splicing of human endogenous retroviruses in cancer. What about head and neck? —A mini review. Front Oncol 2022; 12:1019085. [PMID: 36338752 PMCID: PMC9631305 DOI: 10.3389/fonc.2022.1019085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 10/03/2022] [Indexed: 11/13/2022] Open
Abstract
Human endogenous retroviruses (HERVs) are transcribed in many cancer types, including head and neck cancer. Because of accumulating mutations at proviral loci over evolutionary time, HERVs are functionally defective and cannot complete their viral life cycle. Despite that, HERV transcripts, including full-length viral RNAs and viral RNAs spliced as expected at the conventional viral splice sites, can be detected in particular conditions, such as cancer. Interestingly, non-viral–related transcription, including aberrant, non-conventionally spliced RNAs, has been reported as well. The role of HERV transcription in cancer and its contribution to oncogenesis or progression are still debated. Nonetheless, HERVs may constitute a suitable cancer biomarker or a target for therapy. Thus, ongoing research aims both to clarify the basic mechanisms underlying HERV transcription in cancer and to exploit its potential toward clinical application. In this mini-review, we summarize the current knowledge, the most recent findings, and the future perspectives of research on HERV transcription and splicing, with particular focus on head and neck cancer.
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Shapiro JA. What we have learned about evolutionary genome change in the past 7 decades. Biosystems 2022; 215-216:104669. [DOI: 10.1016/j.biosystems.2022.104669] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/23/2022] [Accepted: 03/23/2022] [Indexed: 12/12/2022]
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Zheng J, Wei Y, Han GZ. The diversity and evolution of retroviruses: perspectives from viral “fossils”. Virol Sin 2022; 37:11-18. [PMID: 35234634 PMCID: PMC8922424 DOI: 10.1016/j.virs.2022.01.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/12/2021] [Indexed: 01/19/2023] Open
Abstract
Retroviruses exclusively infect vertebrates, causing a variety of diseases. The replication of retroviruses requires reverse transcription and integration into host genomes. When infecting germline cells, retroviruses become inherited vertically, forming endogenous retroviruses (ERVs). ERVs document past viral infections, providing molecular fossils for studying the evolutionary history of retroviruses. In this review, we summarize the recent advances in understanding the diversity and evolution of retroviruses from the perspectives of viral fossils, and discuss the effects of ERVs on the evolution of host biology. Recent advances in understanding the diversity and evolution of retroviruses. Methods to analyze ERVs. The effects of ERVs on the evolution of host biology.
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Affiliation(s)
- Jialu Zheng
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Yutong Wei
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Guan-Zhu Han
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China.
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Mao J, Zhang Q, Cong YS. Human endogenous retroviruses in development and disease. Comput Struct Biotechnol J 2021; 19:5978-5986. [PMID: 34849202 PMCID: PMC8604659 DOI: 10.1016/j.csbj.2021.10.037] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 10/29/2021] [Accepted: 10/29/2021] [Indexed: 12/16/2022] Open
Abstract
Human endogenous retroviruses (HERVs) represent ∼8% of human genome, deriving from exogenous retroviral infections of germ line cells occurred millions of years ago and being inherited by the offspring in a Mendelian fashion. Most of HERVs are nonprotein-coding because of the accumulation of mutations, insertions, deletions, and/or truncations. It has been long thought that HERVs were "junk DNA". However, it is now known that HERVs are involved in various biological processes through encoding proteins, acting as promoters/enhancers, or lncRNAs to affect human health and disease. In this review, we summarized recent findings about HERVs, with implications in embryonic development, pluripotency, cancer, aging, and neurodegenerative diseases.
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Affiliation(s)
- Jian Mao
- Key Laboratory of Aging and Cancer Biology of Zhejiang Province, Hangzhou Normal University School of Basic Medical Sciences, Hangzhou, China
| | - Qian Zhang
- Key Laboratory of Aging and Cancer Biology of Zhejiang Province, Hangzhou Normal University School of Basic Medical Sciences, Hangzhou, China
| | - Yu-Sheng Cong
- Key Laboratory of Aging and Cancer Biology of Zhejiang Province, Hangzhou Normal University School of Basic Medical Sciences, Hangzhou, China
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