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Yuan XQ, Zhou N, Song SJ, Xie YX, Chen SQ, Yang TF, Peng X, Zhang CY, Zhu YH, Peng L. Decoding the genomic enigma: Approaches to studying extrachromosomal circular DNA. Heliyon 2024; 10:e36659. [PMID: 39263178 PMCID: PMC11388731 DOI: 10.1016/j.heliyon.2024.e36659] [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: 02/21/2024] [Revised: 08/19/2024] [Accepted: 08/20/2024] [Indexed: 09/13/2024] Open
Abstract
Extrachromosomal circular DNA (eccDNA), a pervasive yet enigmatic component of the eukaryotic genome, exists autonomously from its chromosomal counterparts. Ubiquitous in eukaryotes, eccDNA plays a critical role in the orchestration of cellular processes and the etiology of diseases, particularly cancers. However, the full scope of its influence on health and disease remains elusive, presenting a rich vein of research yet to be mined. Unraveling the complexities of eccDNA necessitates a distillation of methodologies - from biogenesis to functional analysis - a landscape we overview in this study with precision and clarity. Here, we systematically outline cutting-edge methodologies from high-throughput sequencing and bioinformatics to experimental validations, showcasing the intricate world of eccDNAs. We combed through a treasure trove of auxiliary research resources and analytical tools. Moreover, we chart a course for future inquiry, illuminating the horizon with potential groundbreaking strategies for designing eccDNA research projects and pioneering new methodological frontiers.
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Affiliation(s)
- Xiao-Qing Yuan
- Guangdong Provincial Key Laboratory of Cancer Pathogenesis and Precision Diagnosis and Treatment, Shenshan Medical Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Shanwei, 516621, China
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
- Breast Tumor Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Nan Zhou
- The Affiliated Brain Hospital, Guangzhou Medical University, Guangzhou, 510370, China
| | - Shi-Jian Song
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
- Breast Tumor Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Yi-Xia Xie
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Shui-Qin Chen
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Teng-Fei Yang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Xian Peng
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
- Puai Medical College, Shaoyang University, Shaoyang, 422100, China
| | - Chao-Yang Zhang
- Research Unit Analytical Pathology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, 85764, Germany
| | - Ying-Hua Zhu
- Department of Genetic Medicine, Dongguan Children's Hospital Affiliated to Guangdong Medical University, Dongguan, 523325, China
| | - Li Peng
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
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Li F, Ming W, Lu W, Wang Y, Dong X, Bai Y. Bioinformatics advances in eccDNA identification and analysis. Oncogene 2024:10.1038/s41388-024-03138-6. [PMID: 39209966 DOI: 10.1038/s41388-024-03138-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 08/09/2024] [Accepted: 08/16/2024] [Indexed: 09/04/2024]
Abstract
Extrachromosomal circular DNAs (eccDNAs) are a unique class of chromosome-originating circular DNA molecules, which are closely linked to oncogene amplification. Due to recent technological advances, particularly in high-throughput sequencing technology, bioinformatics methods based on sequencing data have become primary approaches for eccDNA identification and functional analysis. Currently, eccDNA-relevant databases incorporate previously identified eccDNA and provide thorough functional annotations and predictions, thereby serving as a valuable resource for eccDNA research. In this review, we collected around 20 available eccDNA-associated bioinformatics tools, including identification tools and annotation databases, and summarized their properties and capabilities. We evaluated some of the eccDNA detection methods in simulated data to offer recommendations for future eccDNA detection. We also discussed the current limitations and prospects of bioinformatics methodologies in eccDNA research.
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Affiliation(s)
- Fuyu Li
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, PR China
| | - Wenlong Ming
- Institute for AI in Medicine, School of Artificial Intelligence, Nanjing University of Information Science and Technology, Nanjing, 210044, PR China.
| | - Wenxiang Lu
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, PR China
| | - Ying Wang
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, PR China
| | - Xianjun Dong
- Adams Center of Parkinson's Disease Research, Yale School of Medicine, Yale University, 100 College St, New Haven, CT, 06511, USA.
- Department of Neurology, Yale School of Medicine, Yale University, 100 College St, New Haven, CT, 06511, USA.
| | - Yunfei Bai
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, PR China.
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Tsiakanikas P, Athanasopoulou K, Darioti IA, Agiassoti VT, Theocharis S, Scorilas A, Adamopoulos PG. Beyond the Chromosome: Recent Developments in Decoding the Significance of Extrachromosomal Circular DNA (eccDNA) in Human Malignancies. Life (Basel) 2024; 14:922. [PMID: 39202666 PMCID: PMC11355349 DOI: 10.3390/life14080922] [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: 06/06/2024] [Revised: 07/13/2024] [Accepted: 07/23/2024] [Indexed: 09/03/2024] Open
Abstract
Extrachromosomal circular DNA (eccDNA) is a form of a circular double-stranded DNA that exists independently of conventional chromosomes. eccDNA exhibits a broad and random distribution across eukaryotic cells and has been associated with tumor-related properties due to its ability to harbor the complete gene information of oncogenes. The complex and multifaceted mechanisms underlying eccDNA formation include pathways such as DNA damage repair, breakage-fusion-bridge (BFB) mechanisms, chromothripsis, and cell apoptosis. Of note, eccDNA plays a pivotal role in tumor development, genetic heterogeneity, and therapeutic resistance. The high copy number and transcriptional activity of oncogenes carried by eccDNA contribute to the accelerated growth of tumors. Notably, the amplification of oncogenes on eccDNA is implicated in the malignant progression of cancer cells. The improvement of high-throughput sequencing techniques has greatly enhanced our knowledge of eccDNA by allowing for a detailed examination of its genetic structures and functions. However, we still lack a comprehensive and efficient annotation for eccDNA, while challenges persist in the study and understanding of the functional role of eccDNA, emphasizing the need for the development of robust methodologies. The potential clinical applications of eccDNA, such as its role as a measurable biomarker or therapeutic target in diseases, particularly within the spectrum of human malignancies, is a promising field for future research. In conclusion, eccDNA represents a quite dynamic and multifunctional genetic entity with far-reaching implications in cancer pathogenesis and beyond. Further research is essential to unravel the molecular pathways of eccDNA formation, elucidate its functional roles, and explore its clinical applications. Addressing these aspects is crucial for advancing our understanding of genomic instability and developing novel strategies for tailored therapeutics, especially in cancer.
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Affiliation(s)
- Panagiotis Tsiakanikas
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, 15701 Athens, Greece
| | - Konstantina Athanasopoulou
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, 15701 Athens, Greece
| | - Ioanna A. Darioti
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, 15701 Athens, Greece
| | - Vasiliki Taxiarchoula Agiassoti
- First Department of Pathology, Medical School, National and Kapodistrian University of Athens, 15772 Athens, Greece; (V.T.A.)
| | - Stamatis Theocharis
- First Department of Pathology, Medical School, National and Kapodistrian University of Athens, 15772 Athens, Greece; (V.T.A.)
| | - Andreas Scorilas
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, 15701 Athens, Greece
| | - Panagiotis G. Adamopoulos
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, 15701 Athens, Greece
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Zhou L, Tang W, Ye B, Zou L. Characterization, biogenesis model, and current bioinformatics of human extrachromosomal circular DNA. Front Genet 2024; 15:1385150. [PMID: 38746056 PMCID: PMC11092383 DOI: 10.3389/fgene.2024.1385150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 04/12/2024] [Indexed: 05/16/2024] Open
Abstract
Human extrachromosomal circular DNA, or eccDNA, has been the topic of extensive investigation in the last decade due to its prominent regulatory role in the development of disorders including cancer. With the rapid advancement of experimental, sequencing and computational technology, millions of eccDNA records are now accessible. Unfortunately, the literature and databases only provide snippets of this information, preventing us from fully understanding eccDNAs. Researchers frequently struggle with the process of selecting algorithms and tools to examine eccDNAs of interest. To explain the underlying formation mechanisms of the five basic classes of eccDNAs, we categorized their characteristics and functions and summarized eight biogenesis theories. Most significantly, we created a clear procedure to help in the selection of suitable techniques and tools and thoroughly examined the most recent experimental and bioinformatics methodologies and data resources for identifying, measuring and analyzing eccDNA sequences. In conclusion, we highlighted the current obstacles and prospective paths for eccDNA research, specifically discussing their probable uses in molecular diagnostics and clinical prediction, with an emphasis on the potential contribution of novel computational strategies.
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Affiliation(s)
- Lina Zhou
- School of Medicine, Chongqing University, Department of Clinical Data Research, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing University, Chongqing, China
| | - Wenyi Tang
- School of Medicine, Chongqing University, Department of Clinical Data Research, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing University, Chongqing, China
| | - Bo Ye
- School of Medicine, Chongqing University, Department of Clinical Data Research, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing University, Chongqing, China
| | - Lingyun Zou
- School of Medicine, Chongqing University, Department of Clinical Data Research, Chongqing Emergency Medical Center, Chongqing University Central Hospital, Chongqing University, Chongqing, China
- School of Medicine, Jinan University, Guangzhou, Guangdong, China
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Merkulov P, Serganova M, Petrov G, Mityukov V, Kirov I. Long-read sequencing of extrachromosomal circular DNA and genome assembly of a Solanum lycopersicum breeding line revealed active LTR retrotransposons originating from S. Peruvianum L. introgressions. BMC Genomics 2024; 25:404. [PMID: 38658857 PMCID: PMC11044480 DOI: 10.1186/s12864-024-10314-1] [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: 12/18/2023] [Accepted: 04/15/2024] [Indexed: 04/26/2024] Open
Abstract
Transposable elements (TEs) are a major force in the evolution of plant genomes. Differences in the transposition activities and landscapes of TEs can vary substantially, even in closely related species. Interspecific hybridization, a widely employed technique in tomato breeding, results in the creation of novel combinations of TEs from distinct species. The implications of this process for TE transposition activity have not been studied in modern cultivars. In this study, we used nanopore sequencing of extrachromosomal circular DNA (eccDNA) and identified two highly active Ty1/Copia LTR retrotransposon families of tomato (Solanum lycopersicum), called Salsa and Ketchup. Elements of these families produce thousands of eccDNAs under controlled conditions and epigenetic stress. EccDNA sequence analysis revealed that the major parts of eccDNA produced by Ketchup and Salsa exhibited low similarity to the S. lycopersicum genomic sequence. To trace the origin of these TEs, whole-genome nanopore sequencing and de novo genome assembly were performed. We found that these TEs occurred in a tomato breeding line via interspecific introgression from S. peruvianum. Our findings collectively show that interspecific introgressions can contribute to both genetic and phenotypic diversity not only by introducing novel genetic variants, but also by importing active transposable elements from other species.
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Affiliation(s)
- Pavel Merkulov
- All-Russia Research Institute of Agricultural Biotechnology, 127550, Moscow, Russia
- Moscow Institute of Physics and Technology, 141701, Dolgoprudny, Russia
| | - Melania Serganova
- All-Russia Research Institute of Agricultural Biotechnology, 127550, Moscow, Russia
- Moscow Institute of Physics and Technology, 141701, Dolgoprudny, Russia
| | - Georgy Petrov
- Moscow Institute of Physics and Technology, 141701, Dolgoprudny, Russia
| | - Vladislav Mityukov
- Skolkovo Institute of Science and Technology, 121205, Moscow, Russia
- Institute for Information Transmission Problems (Kharkevich Institute), Russian Academy of Sciences, 127051, Moscow, Russia
| | - Ilya Kirov
- All-Russia Research Institute of Agricultural Biotechnology, 127550, Moscow, Russia.
- Moscow Institute of Physics and Technology, 141701, Dolgoprudny, Russia.
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Wu N, Wei L, Zhu Z, Liu Q, Li K, Mao F, Qiao J, Zhao X. Innovative insights into extrachromosomal circular DNAs in gynecologic tumors and reproduction. Protein Cell 2024; 15:6-20. [PMID: 37233789 PMCID: PMC10762679 DOI: 10.1093/procel/pwad032] [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: 03/20/2023] [Accepted: 05/03/2023] [Indexed: 05/27/2023] Open
Abstract
Originating but free from chromosomal DNA, extrachromosomal circular DNAs (eccDNAs) are organized in circular form and have long been found in unicellular and multicellular eukaryotes. Their biogenesis and function are poorly understood as they are characterized by sequence homology with linear DNA, for which few detection methods are available. Recent advances in high-throughput sequencing technologies have revealed that eccDNAs play crucial roles in tumor formation, evolution, and drug resistance as well as aging, genomic diversity, and other biological processes, bringing it back to the research hotspot. Several mechanisms of eccDNA formation have been proposed, including the breakage-fusion-bridge (BFB) and translocation-deletion-amplification models. Gynecologic tumors and disorders of embryonic and fetal development are major threats to human reproductive health. The roles of eccDNAs in these pathological processes have been partially elucidated since the first discovery of eccDNA in pig sperm and the double minutes in ovarian cancer ascites. The present review summarized the research history, biogenesis, and currently available detection and analytical methods for eccDNAs and clarified their functions in gynecologic tumors and reproduction. We also proposed the application of eccDNAs as drug targets and liquid biopsy markers for prenatal diagnosis and the early detection, prognosis, and treatment of gynecologic tumors. This review lays theoretical foundations for future investigations into the complex regulatory networks of eccDNAs in vital physiological and pathological processes.
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Affiliation(s)
- Ning Wu
- State Key Laboratory of Female Fertility Promotion, Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Peking University Third Hospital, Beijing 100191, China
- National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing 100191, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing 100191, China
| | - Ling Wei
- Institute of Medical Innovation and Research, Peking University Third Hospital, Beijing 100191, China
- Cancer Center, Peking University Third Hospital, Beijing 100191, China
| | - Zhipeng Zhu
- Institute of Medical Innovation and Research, Peking University Third Hospital, Beijing 100191, China
- Cancer Center, Peking University Third Hospital, Beijing 100191, China
| | - Qiang Liu
- State Key Laboratory of Female Fertility Promotion, Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Peking University Third Hospital, Beijing 100191, China
- National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing 100191, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing 100191, China
| | - Kailong Li
- Department of Biochemistry and Biophysics, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Fengbiao Mao
- Institute of Medical Innovation and Research, Peking University Third Hospital, Beijing 100191, China
- Cancer Center, Peking University Third Hospital, Beijing 100191, China
| | - Jie Qiao
- State Key Laboratory of Female Fertility Promotion, Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Peking University Third Hospital, Beijing 100191, China
- National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing 100191, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing 100191, China
- Beijing Advanced Innovation Center for Genomics, Beijing 100191, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100191, China
| | - Xiaolu Zhao
- State Key Laboratory of Female Fertility Promotion, Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Peking University Third Hospital, Beijing 100191, China
- National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China
- Key Laboratory of Assisted Reproduction (Peking University), Ministry of Education, Beijing 100191, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing 100191, China
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Lu W, Li F, Ouyang Y, Jiang Y, Zhang W, Bai Y. A comprehensive analysis of library preparation methods shows high heterogeneity of extrachromosomal circular DNA but distinct chromosomal amount levels reflecting different cell states. Analyst 2023; 149:148-160. [PMID: 37987554 DOI: 10.1039/d3an01300f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Extrachromosomal circular DNA (eccDNA) was discovered several decades ago, but little is known about its function. With the development of sequencing technology, several library preparation methods have been developed to elucidate the biogenesis and function of eccDNA. However, different treatment methods have certain biases that can lead to their erroneous interpretation. To address these issues, we compared the performance of different library preparation methods. Our investigation revealed that the utilization of rolling-circle amplification (RCA) and restriction enzyme linearization of mitochondrial DNA (mtDNA) significantly enhanced the efficiency of enriching extrachromosomal circular DNA (eccDNA). However, it also introduced certain biases, such as an unclear peak in ∼160-200 bp periodicity and the absence of a typical motif pattern. Furthermore, given that RCA can lead to a disproportionate change in copy numbers, eccDNA quantification using split and discordant reads should be avoided. Analysis of the genomic and elements distribution of the overall population of eccDNA molecules revealed a high correlation between the replicates, and provided a possible stability signature for eccDNA, which could potentially reflect different cell lines or cell states. However, we found only a few eccDNA with identical junction sites in each replicate, showing a high degree of heterogeneity of eccDNA. The emergence of different motif patterns flanking junctional sites in eccDNAs of varying sizes suggests the involvement of multiple potential mechanisms in eccDNA generation. This study comprehensively compares and discusses various essential approaches for eccDNA library preparation, offering valuable insights and practical advice to researchers involved in characterizing eccDNA.
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Affiliation(s)
- Wenxiang Lu
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, Jiangsu, 210096, China.
| | - Fuyu Li
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, Jiangsu, 210096, China.
| | - Yunfei Ouyang
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, Jiangsu, 210096, China.
| | - Yali Jiang
- The Friendship Hospital of Ili Kazakh Autonomous Prefecture, Ili & Jiangsu Joint Institute of Health, Yining, Xinjiang Uygur Autonomous Region, 835000, China
| | - Weizhong Zhang
- Department of Ophthalmology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, China
| | - Yunfei Bai
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, Jiangsu, 210096, China.
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Smalheiser NR. Mobile circular DNAs regulating memory and communication in CNS neurons. Front Mol Neurosci 2023; 16:1304667. [PMID: 38125007 PMCID: PMC10730651 DOI: 10.3389/fnmol.2023.1304667] [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: 09/29/2023] [Accepted: 11/14/2023] [Indexed: 12/23/2023] Open
Abstract
Stimuli that stimulate neurons elicit transcription of immediate-early genes, a process which requires local sites of chromosomal DNA to form double-strand breaks (DSBs) generated by topoisomerase IIb within a few minutes, followed by repair within a few hours. Wakefulness, exploring a novel environment, and contextual fear conditioning also elicit turn-on of synaptic genes requiring DSBs and repair. It has been reported (in non-neuronal cells) that extrachromosomal circular DNA can form at DSBs as the sites are repaired. I propose that activated neurons may generate extrachromosomal circular DNAs during repair at DSB sites, thus creating long-lasting "markers" of that activity pattern which contain sequences from their sites of origin and which regulate long-term gene expression. Although the population of extrachromosomal DNAs is diverse and overall associated with pathology, a subclass of small circular DNAs ("microDNAs," ∼100-400 bases long), largely derives from unique genomic sequences and has attractive features to act as stable, mobile circular DNAs to regulate gene expression in a sequence-specific manner. Circular DNAs can be templates for the transcription of RNAs, particularly small inhibitory siRNAs, circular RNAs and other non-coding RNAs that interact with microRNAs. These may regulate translation and transcription of other genes involved in synaptic plasticity, learning and memory. Another possible fate for mobile DNAs is to be inserted stably into chromosomes after new DSB sites are generated in response to subsequent activation events. Thus, the insertions of mobile DNAs into activity-induced genes may tend to inactivate them and aid in homeostatic regulation to avoid over-excitation, as well as providing a "counter" for a neuron's activation history. Moreover, activated neurons release secretory exosomes that can be transferred to recipient cells to regulate their gene expression. Mobile DNAs may be packaged into exosomes, released in an activity-dependent manner, and transferred to recipient cells, where they may be templates for regulatory RNAs and possibly incorporated into chromosomes. Finally, aging and neurodegenerative diseases (including Alzheimer's disease) are also associated with an increase in DSBs in neurons. It will become important in the future to assess how pathology-associated DSBs may relate to activity-induced mobile DNAs, and whether the latter may potentially contribute to pathogenesis.
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Affiliation(s)
- Neil R. Smalheiser
- Department of Psychiatry, University of Illinois College of Medicine, Chicago, IL, United States
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9
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Li F, Ming W, Lu W, Wang Y, Li X, Dong X, Bai Y. FLED: a full-length eccDNA detector for long-reads sequencing data. Brief Bioinform 2023; 24:bbad388. [PMID: 37930031 PMCID: PMC10632013 DOI: 10.1093/bib/bbad388] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 08/24/2023] [Accepted: 09/30/2023] [Indexed: 11/07/2023] Open
Abstract
Reconstructing the full-length sequence of extrachromosomal circular DNA (eccDNA) from short sequencing reads has proved challenging given the similarity of eccDNAs and their corresponding linear DNAs. Previous sequencing methods were unable to achieve high-throughput detection of full-length eccDNAs. Herein, a novel algorithm was developed, called Full-Length eccDNA Detection (FLED), to reconstruct the sequence of eccDNAs based on the strategy that combined rolling circle amplification and nanopore long-reads sequencing technology. Seven human epithelial and cancer cell line samples were analyzed by FLED and over 5000 full-length eccDNAs were identified per sample. The structures of identified eccDNAs were validated by both Polymerase Chain Reaction (PCR) and Sanger sequencing. Compared to other published nanopore-based eccDNA detectors, FLED exhibited higher sensitivity. In cancer cell lines, the genes overlapped with eccDNA regions were enriched in cancer-related pathways and cis-regulatory elements can be predicted in the upstream or downstream of intact genes on eccDNA molecules, and the expressions of these cancer-related genes were dysregulated in tumor cell lines, indicating the regulatory potency of eccDNAs in biological processes. The proposed method takes advantage of nanopore long reads and enables unbiased reconstruction of full-length eccDNA sequences. FLED is implemented using Python3 which is freely available on GitHub (https://github.com/FuyuLi/FLED).
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Affiliation(s)
- Fuyu Li
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, P. R. China
| | - Wenlong Ming
- Institute for AI in Medicine, School of Artificial Intelligence, Nanjing University of Information Science and Technology, Nanjing, 210044, P. R. China
| | - Wenxiang Lu
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, P. R. China
| | - Ying Wang
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, P. R. China
| | - Xiaohan Li
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, P. R. China
| | - Xianjun Dong
- Genomics and Bioinformatics Hub, Brigham and Women's Hospital, Boston, MA 02115, USA
- Precision Neurology Program, Brigham and Women's Hospital, Boston, MA 02115, USA
- Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Yunfei Bai
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, P. R. China
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10
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Yüksel A, Altungöz O. Gene amplifications and extrachromosomal circular DNAs: function and biogenesis. Mol Biol Rep 2023; 50:7693-7703. [PMID: 37433908 DOI: 10.1007/s11033-023-08649-1] [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] [Received: 08/17/2022] [Accepted: 06/28/2023] [Indexed: 07/13/2023]
Abstract
Gene amplification is an increase in the copy number of restricted chromosomal segments that contain gene(s) and frequently results in the over-expression of the corresponding gene(s). Amplification may be found in the form of extrachromosomal circular DNAs (eccDNAs) or as linear repetitive amplicon regions that are integrated into chromosomes, which may form cytogenetically observable homogeneously staining regions or may be scattered throughout the genome. eccDNAs are structurally circular and in terms of their function and content, they can be classified into various subtypes. They play pivotal roles in many physiological and pathological phenomena such as tumor pathogenesis, aging, maintenance of telomere length and ribosomal DNAs (rDNAs), and gain of resistance against chemotherapeutic agents. Amplification of oncogenes is consistently seen in various types of cancers and can be associated with prognostic factors. eccDNAs are known to be originated from chromosomes as a consequence of various cellular events such as repair processes of damaged DNA or DNA replication errors. In this review, we highlighted the role of gene amplification in cancer, the functional aspects of eccDNAs subtypes, the proposed biogenesis mechanisms, and their role in gene or segmental-DNA amplification.
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Affiliation(s)
- Ali Yüksel
- Department of Medical Biology and Genetics, Institute of Health Sciences, Dokuz Eylul University, 35330, Izmir, Turkey.
| | - Oğuz Altungöz
- Department of Medical Biology and Genetics, Institute of Health Sciences, Dokuz Eylul University, 35330, Izmir, Turkey.
- Department of Medical Biology, Dokuz Eylül Medical School, 35330, Izmir, Turkey.
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Luo X, Zhang L, Cui J, An Q, Li H, Zhang Z, Sun G, Huang W, Li Y, Li C, Jia W, Zou L, Zhao G, Xiao F. Small extrachromosomal circular DNAs as biomarkers for multi-cancer diagnosis and monitoring. Clin Transl Med 2023; 13:e1393. [PMID: 37649244 PMCID: PMC10468585 DOI: 10.1002/ctm2.1393] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 08/15/2023] [Accepted: 08/21/2023] [Indexed: 09/01/2023] Open
Abstract
BACKGROUND Small extrachromosomal circular DNAs (eccDNAs) have the potential to be cancer biomarkers. However, the formation mechanisms and functions of small eccDNAs selected in carcinogenesis are not clear, and whether the small eccDNA profile in the plasma of cancer patients represents that in cancer tissues remains to be elucidated. METHODS A novel sequencing workflow based on the nanopore sequencing platform was used to sequence naturally existing full-length small eccDNAs in tissues and plasma collected from 25 cancer patients (including prostate cancer, hepatocellular carcinoma and colorectal cancer), and from an independent validation cohort (including 7 cancer plasma and 14 healthy plasma). RESULTS Compared with those in non-cancer tissues, small eccDNAs detected in cancer tissues had a significantly larger number and size (P = 0.040 and 2.2e-16, respectively), along with more even distribution and different formation mechanisms. Although small eccDNAs had different general characteristics and genomic annotation between cancer tissues and the paired plasma, they had similar formation mechanisms and cancer-related functions. Small eccDNAs originated from some specific genes had great multi-cancer diagnostic value in tissues (AUC ≥ 0.8) and plasma (AUC > 0.9), especially increasing the accuracy of multi-cancer prediction of CEA/CA19-9 levels. The high multi-cancer diagnostic value of small eccDNAs originated from ALK&ETV6 could be extrapolated from tissues (AUC = 0.804) to plasma and showed high positive predictive value (100%) and negative predictive value (82.35%) in a validation cohort. CONCLUSIONS As independent and stable circular DNA molecules, small eccDNAs in both tissues and plasma can be used as ideal biomarkers for cost-effective multi-cancer diagnosis and monitoring.
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Affiliation(s)
- Xuanmei Luo
- Peking University Fifth School of Clinical MedicineBeijing HospitalNational Center of GerontologyBeijingChina
- The Key Laboratory of GeriatricsBeijing Institute of GeriatricsInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijing HospitalNational Center of Gerontology of National Health CommissionBeijingChina
| | - Lili Zhang
- Clinical BiobankBeijing HospitalNational Center of GerontologyNational Health CommissionInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijingChina
| | - Jian Cui
- Department of General SurgeryBeijing HospitalBeijingChina
| | - Qi An
- Department of General SurgeryBeijing HospitalBeijingChina
| | - Hexin Li
- Clinical BiobankBeijing HospitalNational Center of GerontologyNational Health CommissionInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijingChina
| | - Zaifeng Zhang
- The Key Laboratory of GeriatricsBeijing Institute of GeriatricsInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijing HospitalNational Center of Gerontology of National Health CommissionBeijingChina
| | - Gaoyuan Sun
- Clinical BiobankBeijing HospitalNational Center of GerontologyNational Health CommissionInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijingChina
| | - Wei Huang
- The Key Laboratory of GeriatricsBeijing Institute of GeriatricsInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijing HospitalNational Center of Gerontology of National Health CommissionBeijingChina
| | - Yifei Li
- Clinical BiobankBeijing HospitalNational Center of GerontologyNational Health CommissionInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijingChina
| | - Chang Li
- Peking University Fifth School of Clinical MedicineBeijing HospitalNational Center of GerontologyBeijingChina
- The Key Laboratory of GeriatricsBeijing Institute of GeriatricsInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijing HospitalNational Center of Gerontology of National Health CommissionBeijingChina
| | - Wenzhuo Jia
- Department of General SurgeryBeijing HospitalBeijingChina
- National Center of GerontologyInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijingChina
| | - Lihui Zou
- The Key Laboratory of GeriatricsBeijing Institute of GeriatricsInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijing HospitalNational Center of Gerontology of National Health CommissionBeijingChina
| | - Gang Zhao
- Department of General SurgeryBeijing HospitalBeijingChina
- National Center of GerontologyInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijingChina
| | - Fei Xiao
- Peking University Fifth School of Clinical MedicineBeijing HospitalNational Center of GerontologyBeijingChina
- The Key Laboratory of GeriatricsBeijing Institute of GeriatricsInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijing HospitalNational Center of Gerontology of National Health CommissionBeijingChina
- Clinical BiobankBeijing HospitalNational Center of GerontologyNational Health CommissionInstitute of Geriatric MedicineChinese Academy of Medical SciencesBeijingChina
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Arshadi A, Tolomeo D, Venuto S, Storlazzi CT. Advancements in Focal Amplification Detection in Tumor/Liquid Biopsies and Emerging Clinical Applications. Genes (Basel) 2023; 14:1304. [PMID: 37372484 PMCID: PMC10298061 DOI: 10.3390/genes14061304] [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] [Received: 05/17/2023] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
Focal amplifications (FAs) are crucial in cancer research due to their significant diagnostic, prognostic, and therapeutic implications. FAs manifest in various forms, such as episomes, double minute chromosomes, and homogeneously staining regions, arising through different mechanisms and mainly contributing to cancer cell heterogeneity, the leading cause of drug resistance in therapy. Numerous wet-lab, mainly FISH, PCR-based assays, next-generation sequencing, and bioinformatics approaches have been set up to detect FAs, unravel the internal structure of amplicons, assess their chromatin compaction status, and investigate the transcriptional landscape associated with their occurrence in cancer cells. Most of them are tailored for tumor samples, even at the single-cell level. Conversely, very limited approaches have been set up to detect FAs in liquid biopsies. This evidence suggests the need to improve these non-invasive investigations for early tumor detection, monitoring disease progression, and evaluating treatment response. Despite the potential therapeutic implications of FAs, such as, for example, the use of HER2-specific compounds for patients with ERBB2 amplification, challenges remain, including developing selective and effective FA-targeting agents and understanding the molecular mechanisms underlying FA maintenance and replication. This review details a state-of-the-art of FA investigation, with a particular focus on liquid biopsies and single-cell approaches in tumor samples, emphasizing their potential to revolutionize the future diagnosis, prognosis, and treatment of cancer patients.
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Affiliation(s)
| | | | | | - Clelia Tiziana Storlazzi
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, 70125 Bari, Italy; (A.A.); (D.T.); (S.V.)
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