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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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2
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Bridging PCR: An Efficient and Reliable Scheme Implemented for Genome-Walking. Curr Issues Mol Biol 2023; 45:501-511. [PMID: 36661519 PMCID: PMC9857710 DOI: 10.3390/cimb45010033] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/01/2023] [Accepted: 01/04/2023] [Indexed: 01/09/2023] Open
Abstract
The efficacy of the available genome-walking methods is restricted by low specificity, high background, or composite operations. We herein conceived bridging PCR, an efficient genome-walking approach. Three primers with random sequences, inner walker primer (IWP), bridging primer (BP), and outer walker primer (OWP), are involved in bridging PCR. The BP is fabricated by splicing OWP to the 5'-end of IWP's 5'-part. A bridging PCR set is constituted by three rounds of amplification reactions, sequentially performed by IWP, BP plus OWP, and OWP, respectively pairing with three nested sequence-specific primers (SSP). A non-target product arising from IWP alone undergoes end-lengthening mediated by BP. This modified non-target product is a preferentially formed hairpin between the lengthened ends, instead of binding with shorter OWP. Meanwhile, a non-target product, triggered by SSP alone or SSP plus IWP, is removed by nested SSP. As a result, only the target DNA is accumulated. The efficacy of bridging PCR was validated by walking the gadA/R genes of Levilactobacillus brevis CD0817 and the hyg gene of rice.
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3
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Jia X, Guan R, Cui X, Zhu J, Liu P, Zhang L, Wang D, Zhang Y, Dong K, Wu J, Ji W, Ji G, Bai J, Yu J, Yu Y, Sun W, Zhang F, Fu S. Molecular structure and evolution mechanism of two populations of double minutes in human colorectal cancer cells. J Cell Mol Med 2020; 24:14205-14216. [PMID: 33124133 PMCID: PMC7754069 DOI: 10.1111/jcmm.16035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/26/2020] [Accepted: 10/11/2020] [Indexed: 12/13/2022] Open
Abstract
Gene amplification chiefly manifests as homogeneously stained regions (HSRs) or double minutes (DMs) in cytogenetically and extrachromosomal DNA (ecDNA) in molecular genetics. Evidence suggests that gene amplification is becoming a hotspot for cancer research, which may be a new treatment strategy for cancer. DMs usually carry oncogenes or chemoresistant genes that are associated with cancer progression, occurrence and prognosis. Defining the molecular structure of DMs will facilitate understanding of the molecular mechanism of tumorigenesis. In this study, we re‐identified the origin and integral sequence of DMs in human colorectal adenocarcinoma cell line NCI‐H716 by genetic mapping and sequencing strategy, employing high‐resolution array‐based comparative genomic hybridization, high‐throughput sequencing, multiplex‐fluorescence in situ hybridization and chromosome walking techniques. We identified two distinct populations of DMs in NCI‐H716, confirming their heterogeneity in cancer cells, and managed to construct their molecular structure, which were not investigated before. Research evidence of amplicons distribution in two different populations of DMs suggested that a multi‐step evolutionary model could fit the module of DM genesis better in NCI‐H716 cell line. In conclusion, our data implicated that DMs play a very important role in cancer progression and further investigation is necessary to uncover the role of the DMs.
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Affiliation(s)
- Xueyuan Jia
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
| | - Rongwei Guan
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
| | - Xiaobo Cui
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
| | - Jing Zhu
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
| | - Peng Liu
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
| | - Ling Zhang
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai, China.,Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai, China
| | - Dong Wang
- Scientific Research Centre, the Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yang Zhang
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China
| | - Kexian Dong
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
| | - Jie Wu
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
| | - Wei Ji
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
| | - Guohua Ji
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
| | - Jing Bai
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
| | - Jingcui Yu
- Scientific Research Centre, the Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yang Yu
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
| | - Wenjing Sun
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
| | - Feng Zhang
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai, China.,Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai, China
| | - Songbin Fu
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.,Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education, Harbin Medical University, Harbin, China
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4
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Fan HN, Chen W, Peng SQ, Chen XY, Zhang R, Liang R, Liu H, Zhu JS, Zhang J. Sanguinarine inhibits the tumorigenesis of gastric cancer by regulating the TOX/DNA-PKcs/ KU70/80 pathway. Pathol Res Pract 2019; 215:152677. [DOI: 10.1016/j.prp.2019.152677] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 09/17/2019] [Accepted: 09/27/2019] [Indexed: 02/08/2023]
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5
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Cai M, Zhang H, Hou L, Gao W, Song Y, Cui X, Li C, Guan R, Ma J, Wang X, Han Y, Lv Y, Chen F, Wang P, Meng X, Fu S. Inhibiting homologous recombination decreases extrachromosomal amplification but has no effect on intrachromosomal amplification in methotrexate-resistant colon cancer cells. Int J Cancer 2018; 144:1037-1048. [PMID: 30070702 PMCID: PMC6586039 DOI: 10.1002/ijc.31781] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 02/23/2018] [Accepted: 07/24/2018] [Indexed: 01/08/2023]
Abstract
Gene amplification, which involves the two major topographical structures double minutes (DMs) and homegeneously stained region (HSR), is a common mechanism of treatment resistance in cancer and is initiated by DNA double‐strand breaks. NHEJ, one of DSB repair pathways, is involved in gene amplification as we demonstrated previously. However, the involvement of homologous recombination, another DSB repair pathway, in gene amplification remains to be explored. To better understand the association between HR and gene amplification, we detected HR activity in DM‐ and HSR‐containing MTX‐resistant HT‐29 colon cancer cells. In DM‐containing MTX‐resistant cells, we found increased homologous recombination activity compared with that in MTX‐sensitive cells. Therefore, we suppressed HR activity by silencing BRCA1, the key player in the HR pathway. The attenuation of HR activity decreased the numbers of DMs and DM‐form amplified gene copies and increased the exclusion of micronuclei and nuclear buds that contained DM‐form amplification; these changes were accompanied by cell cycle acceleration and increased MTX sensitivity. In contrast, BRCA1 silencing did not influence the number of amplified genes and MTX sensitivity in HSR‐containing MTX‐resistant cells. In conclusion, our results suggest that the HR pathway plays different roles in extrachromosomal and intrachromosomal gene amplification and may be a new target to improve chemotherapeutic outcome by decreasing extrachromosomal amplification in cancer. What's new? Double‐strand DNA breaks (DSBs) initiate gene amplification, a phenomenon associated with therapeutic resistance in cancer that involves two topographical structures, double minutes (DMs) and homogeneously staining regions (HSRs). Whether DSB repair pathways, particularly homologous recombination (HR), also influence gene amplification is unknown. Here, in methotrexate‐resistant colon cancer cells, HR inhibition effectively reduced gene amplification, specifically the DM‐form, by blocking DM formation and promoting DM exclusion via micronuclei. HR inhibition had no influence on the HSR‐form of gene amplification. Loss of gene amplification by HR inhibition, through partial reversal of methotrexate resistance, may contribute to improved chemotherapeutic outcome.
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Affiliation(s)
- Mengdi Cai
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Huishu Zhang
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Liqing Hou
- Department of Genetics, Inner Mongolia Maternal and Child Care Hospital, Hohhot, Inner Mongolia Autonomous Region, China
| | - Wei Gao
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Ying Song
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Xiaobo Cui
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Chunxiang Li
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Rongwei Guan
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Jinfa Ma
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Xu Wang
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Yue Han
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Yafan Lv
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Feng Chen
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Ping Wang
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Xiangning Meng
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
| | - Songbin Fu
- Laboratory of Medical Genetics, Harbin Medical University, Harbin, 150081, China
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6
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Baldazzi C, Luatti S, Zuffa E, Papayannidis C, Ottaviani E, Marzocchi G, Ameli G, Bardi MA, Bonaldi L, Paolini R, Gurrieri C, Rigolin GM, Cuneo A, Martinelli G, Cavo M, Testoni N. Complex chromosomal rearrangements leading to MECOM overexpression are recurrent in myeloid malignancies with various 3q abnormalities. Genes Chromosomes Cancer 2016; 55:375-88. [PMID: 26815134 DOI: 10.1002/gcc.22341] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 11/25/2015] [Accepted: 12/03/2015] [Indexed: 12/12/2022] Open
Abstract
Chromosomal rearrangements involving 3q26 are recurrent findings in myeloid malignancies leading to MECOM overexpression, which has been associated with a very poor prognosis. Other 3q abnormalities have been reported and cryptic MECOM rearrangements have been identified in some cases. By fluorescence in situ hybridization (FISH) analysis, we investigated 97 acute myeloid leukemia/myelodysplastic syndrome patients with various 3q abnormalities to determine the role and the frequency of the involvement of MECOM. We identified MECOM rearrangements in 51 patients, most of them showed 3q26 involvement by chromosome banding analysis (CBA): inv(3)/t(3;3) (n = 26) and other balanced 3q26 translocations (t(3q26)) (n = 15); the remaining cases (n = 10) showed various 3q abnormalities: five with balanced translocations involving 3q21 or 3q25; two with homogenously staining region (hsr) on 3q; and three with other various 3q abnormalities. Complex rearrangements with multiple breakpoints on 3q, masking 3q26 involvement, were identified in cases with 3q21/3q25 translocations. Furthermore, multiple breaks were observed in two cases with t(3q26), suggesting that complex rearrangement may also occur in apparently simple t(3q26). Intrachromosomal gene amplification was another mechanism leading to MECOM overexpression in two cases with hsr on 3q. In the last three cases, FISH analysis revealed 3q26 involvement that was missed by CBA because of metaphases' suboptimal quality. All cases with MECOM rearrangements showed overexpression by real-time quantitative PCR. Finally, MECOM rearrangements can occur in patients with 3q abnormalities even in the absence of specific 3q26 involvement, underlining that their frequency is underestimated. As MECOM rearrangement has been associated with very poor prognosis, its screening should be performed in patients with any 3q abnormalities.
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Affiliation(s)
- Carmen Baldazzi
- Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology and Medical Oncology "Seragnoli," Sant'Orsola-Malpighi Hospital-University, Bologna, Italy
| | - Simona Luatti
- Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology and Medical Oncology "Seragnoli," Sant'Orsola-Malpighi Hospital-University, Bologna, Italy
| | - Elisa Zuffa
- Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology and Medical Oncology "Seragnoli," Sant'Orsola-Malpighi Hospital-University, Bologna, Italy
| | - Cristina Papayannidis
- Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology and Medical Oncology "Seragnoli," Sant'Orsola-Malpighi Hospital-University, Bologna, Italy
| | - Emanuela Ottaviani
- Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology and Medical Oncology "Seragnoli," Sant'Orsola-Malpighi Hospital-University, Bologna, Italy
| | - Giulia Marzocchi
- Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology and Medical Oncology "Seragnoli," Sant'Orsola-Malpighi Hospital-University, Bologna, Italy
| | - Gaia Ameli
- Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology and Medical Oncology "Seragnoli," Sant'Orsola-Malpighi Hospital-University, Bologna, Italy
| | - Maria Antonella Bardi
- Department of Medical Sciences, University of Ferrara-Arcispedale Sant'Anna, Ferrara, Italy
| | - Laura Bonaldi
- Immunology and Molecular Oncology Unit, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy
| | - Rossella Paolini
- Department of General Medicine, UOSD Hematology, Santa Maria Della Misericordia Hospital, Rovigo, Italy
| | - Carmela Gurrieri
- Immunology and Molecular Oncology Unit, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy
| | - Gian Matteo Rigolin
- Department of Medical Sciences, University of Ferrara-Arcispedale Sant'Anna, Ferrara, Italy
| | - Antonio Cuneo
- Department of Medical Sciences, University of Ferrara-Arcispedale Sant'Anna, Ferrara, Italy
| | - Giovanni Martinelli
- Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology and Medical Oncology "Seragnoli," Sant'Orsola-Malpighi Hospital-University, Bologna, Italy
| | - Michele Cavo
- Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology and Medical Oncology "Seragnoli," Sant'Orsola-Malpighi Hospital-University, Bologna, Italy
| | - Nicoletta Testoni
- Department of Experimental, Diagnostic and Specialty Medicine, Institute of Hematology and Medical Oncology "Seragnoli," Sant'Orsola-Malpighi Hospital-University, Bologna, Italy
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7
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Vogt N, Gibaud A, Lemoine F, de la Grange P, Debatisse M, Malfoy B. Amplicon rearrangements during the extrachromosomal and intrachromosomal amplification process in a glioma. Nucleic Acids Res 2014; 42:13194-205. [PMID: 25378339 PMCID: PMC4245956 DOI: 10.1093/nar/gku1101] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 10/22/2014] [Accepted: 10/23/2014] [Indexed: 01/18/2023] Open
Abstract
The mechanisms of gene amplification in tumour cells are poorly understood and the relationship between extrachromosomal DNA molecules, named double minutes (dmins), and intrachromosomal homogeneously staining regions (hsr) is not documented at nucleotide resolution. Using fluorescent in situ hybridization and whole genome sequencing, we studied a xenografted human oligodendroglioma where the co-amplification of the EGFR and MYC loci was present in the form of dmins at early passages and of an hsr at later passages. The amplified regions underwent multiple rearrangements and deletions during the formation of the dmins and their transformation into hsr. In both forms of amplification, non-homologous end-joining and microhomology-mediated end-joining rather than replication repair mechanisms prevailed in fusions. Small fragments, some of a few tens of base pairs, were associated in contigs. They came from clusters of breakpoints localized hundreds of kilobases apart in the amplified regions. The characteristics of some pairs of junctions suggest that at least some fragments were not fused randomly but could result from the concomitant repair of neighbouring breakpoints during the interaction of remote DNA sequences. This characterization at nucleotide resolution of the transition between extra- and intrachromosome amplifications highlights a hitherto uncharacterized organization of the amplified regions suggesting the involvement of new mechanisms in their formation.
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Affiliation(s)
- Nicolas Vogt
- Institut Curie, Centre de Recherche, F-75248 Paris, France CNRS, UMR3244, F-75248 Paris, France UPMC, F-75248 Paris, France
| | - Anne Gibaud
- Institut Curie, Centre de Recherche, F-75248 Paris, France CNRS, UMR3244, F-75248 Paris, France UPMC, F-75248 Paris, France
| | | | | | - Michelle Debatisse
- Institut Curie, Centre de Recherche, F-75248 Paris, France CNRS, UMR3244, F-75248 Paris, France UPMC, F-75248 Paris, France
| | - Bernard Malfoy
- Institut Curie, Centre de Recherche, F-75248 Paris, France CNRS, UMR3244, F-75248 Paris, France UPMC, F-75248 Paris, France
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8
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Georgakilas AG, Tsantoulis P, Kotsinas A, Michalopoulos I, Townsend P, Gorgoulis VG. Are common fragile sites merely structural domains or highly organized "functional" units susceptible to oncogenic stress? Cell Mol Life Sci 2014; 71:4519-44. [PMID: 25238782 PMCID: PMC4232749 DOI: 10.1007/s00018-014-1717-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 01/07/2023]
Abstract
Common fragile sites (CFSs) are regions of the genome with a predisposition to DNA double-strand breaks in response to intrinsic (oncogenic) or extrinsic replication stress. CFS breakage is a common feature in carcinogenesis from its earliest stages. Given that a number of oncogenes and tumor suppressors are located within CFSs, a question that emerges is whether fragility in these regions is only a structural “passive” incident or an event with a profound biological effect. Furthermore, there is sparse evidence that other elements, like non-coding RNAs, are positioned with them. By analyzing data from various libraries, like miRbase and ENCODE, we show a prevalence of various cancer-related genes, miRNAs, and regulatory binding sites, such as CTCF within CFSs. We propose that CFSs are not only susceptible structural domains, but highly organized “functional” entities that when targeted, severe repercussion for cell homeostasis occurs.
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Affiliation(s)
- Alexandros G Georgakilas
- Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of Athens (NTUA), Zografou, 15780, Athens, Greece
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9
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How a replication origin and matrix attachment region accelerate gene amplification under replication stress in mammalian cells. PLoS One 2014; 9:e103439. [PMID: 25061979 PMCID: PMC4111587 DOI: 10.1371/journal.pone.0103439] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/02/2014] [Indexed: 11/19/2022] Open
Abstract
The gene amplification plays a critical role in the malignant transformation of mammalian cells. The most widespread method for amplifying a target gene in cell culture is the use of methotrexate (Mtx) treatment to amplify dihydrofolate reductase (Dhfr). Whereas, we found that a plasmid bearing both a mammalian origin of replication (initiation region; IR) and a matrix attachment region (MAR) was spontaneously amplified in mammalian cells. In this study, we attempted to uncover the underlying mechanism by which the IR/MAR sequence might accelerate Mtx induced Dhfr amplification. The plasmid containing the IR/MAR was extrachromosomally amplified, and then integrated at multiple chromosomal locations within individual cells, increasing the likelihood that the plasmid might be inserted into a chromosomal environment that permits high expression and further amplification. Efficient amplification of this plasmid alleviated the genotoxicity of Mtx. Clone-based cytogenetic and sequence analysis revealed that the plasmid was amplified in a chromosomal context by breakage-fusion-bridge cycles operating either at the plasmid repeat or at the flanking fragile site activated by Mtx. This mechanism explains how a circular molecule bearing IR/MAR sequences of chromosomal origin might be amplified under replication stress, and also provides insight into gene amplification in human cancer.
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10
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L'Abbate A, Macchia G, D'Addabbo P, Lonoce A, Tolomeo D, Trombetta D, Kok K, Bartenhagen C, Whelan CW, Palumbo O, Severgnini M, Cifola I, Dugas M, Carella M, De Bellis G, Rocchi M, Carbone L, Storlazzi CT. Genomic organization and evolution of double minutes/homogeneously staining regions with MYC amplification in human cancer. Nucleic Acids Res 2014; 42:9131-45. [PMID: 25034695 PMCID: PMC4132716 DOI: 10.1093/nar/gku590] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The mechanism for generating double minutes chromosomes (dmin) and homogeneously staining regions (hsr) in cancer is still poorly understood. Through an integrated approach combining next-generation sequencing, single nucleotide polymorphism array, fluorescent in situ hybridization and polymerase chain reaction-based techniques, we inferred the fine structure of MYC-containing dmin/hsr amplicons harboring sequences from several different chromosomes in seven tumor cell lines, and characterized an unprecedented number of hsr insertion sites. Local chromosome shattering involving a single-step catastrophic event (chromothripsis) was recently proposed to explain clustered chromosomal rearrangements and genomic amplifications in cancer. Our bioinformatics analyses based on the listed criteria to define chromothripsis led us to exclude it as the driving force underlying amplicon genesis in our samples. Instead, the finding of coexisting heterogeneous amplicons, differing in their complexity and chromosome content, in cell lines derived from the same tumor indicated the occurrence of a multi-step evolutionary process in the genesis of dmin/hsr. Our integrated approach allowed us to gather a complete view of the complex chromosome rearrangements occurring within MYC amplicons, suggesting that more than one model may be invoked to explain the origin of dmin/hsr in cancer. Finally, we identified PVT1 as a target of fusion events, confirming its role as breakpoint hotspot in MYC amplification.
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Affiliation(s)
| | - Gemma Macchia
- Department of Biology, University of Bari, Bari, Italy
| | | | - Angelo Lonoce
- Department of Biology, University of Bari, Bari, Italy
| | - Doron Tolomeo
- Department of Biology, University of Bari, Bari, Italy
| | - Domenico Trombetta
- Laboratory of Oncology, IRCCS Casa Sollievo della Sofferenza Hospital, San Giovanni Rotondo, Italy
| | - Klaas Kok
- Department of Genetics, University of Groningen, Groningen, The Netherlands
| | | | | | - Orazio Palumbo
- Medical Genetics Unit, IRCCS Casa Sollievo della Sofferenza Hospital, San Giovanni Rotondo, Italy
| | - Marco Severgnini
- Institute for Biomedical Technologies, National Research Council, Milan, Italy
| | - Ingrid Cifola
- Institute for Biomedical Technologies, National Research Council, Milan, Italy
| | - Martin Dugas
- Institute of Medical Informatics, University of Münster, Münster, Germany
| | - Massimo Carella
- Medical Genetics Unit, IRCCS Casa Sollievo della Sofferenza Hospital, San Giovanni Rotondo, Italy
| | - Gianluca De Bellis
- Institute for Biomedical Technologies, National Research Council, Milan, Italy
| | | | - Lucia Carbone
- National Primate Research Center, Beaverton, Oregon, USA
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11
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Zhang CZ, Leibowitz ML, Pellman D. Chromothripsis and beyond: rapid genome evolution from complex chromosomal rearrangements. Genes Dev 2013; 27:2513-30. [PMID: 24298051 PMCID: PMC3861665 DOI: 10.1101/gad.229559.113] [Citation(s) in RCA: 177] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Recent genome sequencing studies have identified several classes of complex genomic rearrangements that appear to be derived from a single catastrophic event. These discoveries identify ways that genomes can be altered in single large jumps rather than by many incremental steps. Here we compare and contrast these phenomena and examine the evidence that they arise "all at once." We consider the impact of massive chromosomal change for the development of diseases such as cancer and for evolution more generally. Finally, we summarize current models for underlying mechanisms and discuss strategies for testing these models.
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Affiliation(s)
- Cheng-Zhong Zhang
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Mitchell L. Leibowitz
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - David Pellman
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Howard Hughes Medical Institute, Boston, Massachusetts 02115, USA
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Li W, Xie C, Yang Z, Chen J, Lu NH. Abnormal DNA-PKcs and Ku 70/80 expression may promote malignant pathological processes in gastric carcinoma. World J Gastroenterol 2013; 19:6894-901. [PMID: 24187467 PMCID: PMC3812491 DOI: 10.3748/wjg.v19.i40.6894] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 09/04/2013] [Accepted: 09/15/2013] [Indexed: 02/06/2023] Open
Abstract
AIM To determine the expression of the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) and the Ku70/Ku80 heterodimer (Ku 70/80) in gastric carcinoma. METHODS Gastric biopsies were obtained from 146 gastric carcinoma patients [Helicobacter pylori (H. pylori)-negative: 89 and H. pylori-positive: 57] and 34 from normal subjects (H. pylori-negative: 16 and H. pylori-positive: 18) via surgery and endoscopic detection from April 2011 to August 2012 at the First Affiliated Hospital of Nanchang University. Pathological diagnosis and classification were made according to the criteria of the World Health Organization and the updated Sydney system. An ''in-house'' rapid urease test and modified Giemsa staining were employed to detect H. pylori infection. The expression of DNA-PKcs and the Ku 70/80 protein was detected by immunohistochemistry. RESULTS Overall, the positive rates of both DNA-PKcs and Ku 70/80 were significantly increased in gastric cancer (χ(2) = 133.04, P < 0.001 for DNA-PKcs and χ(2) = 13.06, P < 0.01 for Ku) compared with normal gastric mucosa. There was hardly any detectable expression of DNA-PKcs in normal gastric mucosa, and the positive rate of DNA-PKcs protein expression in patients with a normal gastric mucosa was 0% (0/34), whereas the rate in gastric cancer (GC) was 93.8% (137/146). The difference between the two groups was statistically significant. Additionally, the positive rate of Ku 70/80 was 79.4% (27/34) in normal gastric mucosa and 96.6% (141/146) in gastric cancer. The DNA-PKcs protein level was significantly increased in gastric cancer (Mann-Whitney U = 39.00, P < 0.001), compared with normal gastric mucosa. In addition, there was a significant difference in the expression of Ku 70/80 (Mann-Whitney U = 1117.00, P < 0.001) between gastric cancer and normal gastric mucosa. There was also a significant difference in Ku70/80 protein expression between GC patients with and without H. pylori infection (P < 0.05). Spearman analysis showed a negative correlation between tumor differentiation and DNA-PKcs expression (r = -0.447, P < 0.05). Moreover, Ku70/80 expression was negatively correlated with both clinical stage (r = -0.189, P < 0.05) and H. pylori colonization (r = -0.168, P < 0.05). CONCLUSION Overall, this research demonstrated that enhanced DNA-PKcs and Ku 70/80 expression may be closely associated with gastric carcinoma.
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