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Klapwijk JC, Del Rio Espinola A, Libertini S, Collin P, Fellows MD, Jobling S, Lynch AM, Martus H, Vickers C, Zeller A, Biasco L, Brugman MH, Bushmann FD, Cathomen T, Ertl HCJ, Gabriel R, Gao G, Jadlowsky JK, Kimber I, Lanz TA, Levine BL, Micklethwaite KP, Onodera M, Pizzurro DM, Reed S, Rothe M, Sabatino D, Salk JJ, Schambach A, Themis M, Yuan J. Improving the assessment of risk factors relevant to potential carcinogenicity of gene therapies: a consensus paper. Hum Gene Ther 2024. [PMID: 39049734 DOI: 10.1089/hum.2024.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024] Open
Abstract
Regulators and industry are actively seeking improvements and alternatives to current models and approaches to evaluate potential carcinogenicity of gene therapies (GTs). A meeting of invited experts was organised by NC3Rs/UKEMS (London, March 2023) to discuss this topic. This paper describes the consensus reached amongst delegates on the definition of vector genotoxicity, sources of uncertainty, suitable toxicological endpoints for genotoxic assessment of GTs, and future research needs. The collected recommendations should inform the further development of regulatory guidelines for the non-clinical toxicological assessment of GT products.
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Affiliation(s)
- Jan C Klapwijk
- Cornelis Consulting Ltd, Ware, United Kingdom of Great Britain and Northern Ireland;
| | | | - Silvana Libertini
- Novartis Institutes for BioMedical Research Basel, Basel, Basel-Stadt, Switzerland;
| | - Philippe Collin
- AstraZeneca R&D Cambridge, Clinical Pharmacology and Safety Sciences, BioPharmaceuticals R&D, Cambridge, United Kingdom of Great Britain and Northern Ireland;
| | - Mick D Fellows
- AstraZeneca R&D Cambridge, Clinical Pharmacology and Safety Sciences, BioPharmaceuticals R&D, Cambridge, United Kingdom of Great Britain and Northern Ireland;
| | - Susan Jobling
- TestaVec Ltd, Maidenhead, United Kingdom of Great Britain and Northern Ireland
- Brunel University London, Division of Biosciences, Department of Life Sciences, College of Health and Life Sciences, Uxbridge, Greater London, United Kingdom of Great Britain and Northern Ireland;
| | - Antohny M Lynch
- GlaxoSmithKline, Genetic Toxicology, Ware, United Kingdom of Great Britain and Northern Ireland;
| | - HansJoerg Martus
- Novartis Institutes for BioMedical Research Basel, Basel, Basel-Stadt, Switzerland;
| | - Catherine Vickers
- National Centre for the Replacement Refinement and Reduction of Animals in Research, London, United Kingdom of Great Britain and Northern Ireland;
| | - Andreas Zeller
- F Hoffmann-La Roche Ltd, pRED, Pharma Research & Early Development , Roche Innovation Center, Basel, Switzerland;
| | - Luca Biasco
- UCL, Zayed Centre for Research (ZCR), London, United Kingdom of Great Britain and Northern Ireland;
| | - Martijn H Brugman
- GlaxoSmithKline Research & Development Limited, Cell and Gene Therapy, GSK Medicine Research Centre, Stevenage, Hertfordshire, United Kingdom of Great Britain and Northern Ireland;
| | - Frederic D Bushmann
- University of Pennsylvania Perelman School of Medicine, Department of Microbiology, Philadelphia, Pennsylvania, United States;
| | - Toni Cathomen
- University Medical Center Freiburg, Institute for Transfusion Medicine and Gene Therapy, Hugstetter Str. 55, Freiburg, Germany, 79106;
| | - Hildegund C J Ertl
- Wistar Institute of Anatomy and Biology, Ertl Laboratory Vaccine & Immunotherapy Center, Philadelphia, Pennsylvania, United States;
| | | | - Guangping Gao
- University of Massachusetts Medical School, Horae Gene Therapy Center, Worcester, Massachusetts, United States;
| | - Julie K Jadlowsky
- University of Pennsylvania Perelman School of Medicine, Center for Cellular Immunotherapies and Department of Pathology and Laboratory Medicine, Philadelphia, Pennsylvania, United States;
| | - Ian Kimber
- The University of Manchester, Faculty of Biology, Medicine and Health, Manchester, United Kingdom of Great Britain and Northern Ireland;
| | - Thomas A Lanz
- Pfizer Global Research and Development, Drug Safety Research & Development, Groton, Connecticut, United States;
| | - Bruce L Levine
- University of Pennsylvania Perelman School of Medicine, Center for Cellular Immunotherapies and Department of Pathology and Laboratory Medicine, Philadelphia, Pennsylvania, United States;
| | - Kenneth P Micklethwaite
- Westmead Hospital, Blood Transplant and Cell Therapies Program, Department of Haematology, Westmead, New South Wales, Australia
- Westmead Hospital ICPMR, NSW Health Pathology Blood Transplant and Cell Therapies Laboratory , Westmead, New South Wales, Australia
- Westmead Institute for Medical Research, Westmead, New South Wales, Australia
- The University of Sydney Sydney Medical School, Sydney, New South Wales, Australia;
| | - Masafumi Onodera
- National Center for Child Health and Development, Gene & Cell Therapy Promotion Center, Setagaya-ku, Tokyo, Japan;
| | | | - Simon Reed
- Cardiff University School of Medicine, Division of Cancer and Genetics, Cardiff, Cardiff, United Kingdom of Great Britain and Northern Ireland;
| | - Michael Rothe
- Hannover Medical School, Institute of Experimental Hematology, Hannover, Niedersachsen, Germany;
| | - Denise Sabatino
- University of Pennsylvania School of Medicine, Pediatrics, The Children's Hospital of Philadelphia, 3501 Civic Center Blvd, Colket Translational Research Blg, Rm 5020, Philadelphia, Pennsylvania, United States, 19104
- The Children's Hospital of Philadelphia;
| | - Jesse J Salk
- TwinStrand Biosciences, Seattle, Washington, United States
- University of Washington School of Medicine, Department of Medicine, Divisions of Hematology and Medical Oncology, Seattle, Washington, United States;
| | - Axel Schambach
- Hannover Medical School, Institute of Experimental Hematology, Hannover, Germany
- Boston Children's Hospital, Division of Hematology/Oncology, Boston, Massachusetts, United States;
| | - Michael Themis
- TestaVec Ltd, London, Greater London, United Kingdom of Great Britain and Northern Ireland
- Brunel University London, Division of Biosciences, Department of Life Sciences, College of Health and Life Sciences, Uxbridge, United Kingdom of Great Britain and Northern Ireland;
| | - Jing Yuan
- Kymera Therapeutics Inc, Watertown, Massachusetts, United States;
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Zhang X, Celic I, Mitchell H, Stuckert S, Vedula L, Han J. Comprehensive profiling of L1 retrotransposons in mouse. Nucleic Acids Res 2024; 52:5166-5178. [PMID: 38647072 PMCID: PMC11109951 DOI: 10.1093/nar/gkae273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 03/25/2024] [Accepted: 04/06/2024] [Indexed: 04/25/2024] Open
Abstract
L1 elements are retrotransposons currently active in mammals. Although L1s are typically silenced in most normal tissues, elevated L1 expression is associated with a variety of conditions, including cancer, aging, infertility and neurological disease. These associations have raised interest in the mapping of human endogenous de novo L1 insertions, and a variety of methods have been developed for this purpose. Adapting these methods to mouse genomes would allow us to monitor endogenous in vivo L1 activity in controlled, experimental conditions using mouse disease models. Here, we use a modified version of transposon insertion profiling, called nanoTIPseq, to selectively enrich young mouse L1s. By linking this amplification step with nanopore sequencing, we identified >95% annotated L1s from C57BL/6 genomic DNA using only 200 000 sequencing reads. In the process, we discovered 82 unannotated L1 insertions from a single C57BL/6 genome. Most of these unannotated L1s were near repetitive sequence and were not found with short-read TIPseq. We used nanoTIPseq on individual mouse breast cancer cells and were able to identify the annotated and unannotated L1s, as well as new insertions specific to individual cells, providing proof of principle for using nanoTIPseq to interrogate retrotransposition activity at the single-cell level in vivo.
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Affiliation(s)
- Xuanming Zhang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Ivana Celic
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Hannah Mitchell
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Sam Stuckert
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Lalitha Vedula
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Jeffrey S Han
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
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3
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Lemmens M, Dorsheimer L, Zeller A, Dietz-Baum Y. Non-clinical safety assessment of novel drug modalities: Genome safety perspectives on viral-, nuclease- and nucleotide-based gene therapies. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2024; 896:503767. [PMID: 38821669 DOI: 10.1016/j.mrgentox.2024.503767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 04/08/2024] [Accepted: 05/13/2024] [Indexed: 06/02/2024]
Abstract
Gene therapies have emerged as promising treatments for various conditions including inherited diseases as well as cancer. Ensuring their safe clinical application requires the development of appropriate safety testing strategies. Several guidelines have been provided by health authorities to address these concerns. These guidelines state that non-clinical testing should be carried out on a case-by-case basis depending on the modality. This review focuses on the genome safety assessment of frequently used gene therapy modalities, namely Adeno Associated Viruses (AAVs), Lentiviruses, designer nucleases and mRNAs. Important safety considerations for these modalities, amongst others, are vector integrations into the patient genome (insertional mutagenesis) and off-target editing. Taking into account the constraints of in vivo studies, health authorities endorse the development of novel approach methodologies (NAMs), which are innovative in vitro strategies for genotoxicity testing. This review provides an overview of NAMs applied to viral and CRISPR/Cas9 safety, including next generation sequencing-based methods for integration site analysis and off-target editing. Additionally, NAMs to evaluate the oncogenicity risk arising from unwanted genomic modifications are discussed. Thus, a range of promising techniques are available to support the safe development of gene therapies. Thorough validation, comparisons and correlations with clinical outcomes are essential to identify the most reliable safety testing strategies. By providing a comprehensive overview of these NAMs, this review aims to contribute to a better understanding of the genome safety perspectives of gene therapies.
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Affiliation(s)
| | - Lena Dorsheimer
- Research and Development, Preclinical Safety, Sanofi, Industriepark Hoechst, Frankfurt am Main 65926, Germany.
| | - Andreas Zeller
- Pharmaceutical Sciences, pRED Innovation Center Basel, Hoffmann-La Roche Ltd, Basel 4070, Switzerland
| | - Yasmin Dietz-Baum
- Research and Development, Preclinical Safety, Sanofi, Industriepark Hoechst, Frankfurt am Main 65926, Germany
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Allen AG, Khan SQ, Margulies CM, Viswanathan R, Lele S, Blaha L, Scott SN, Izzo KM, Gerew A, Pattali R, Cochran NR, Holland CS, Zhao AH, Sherman SE, Jaskolka MC, Wu M, Wilson AC, Sun X, Ciulla DM, Zhang D, Nelson JD, Zhang P, Mazzucato P, Huang Y, Giannoukos G, Marco E, Nehil M, Follit JA, Chang KH, Shearman MS, Wilson CJ, Zuris JA. A highly efficient transgene knock-in technology in clinically relevant cell types. Nat Biotechnol 2024; 42:458-469. [PMID: 37127662 DOI: 10.1038/s41587-023-01779-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 04/04/2023] [Indexed: 05/03/2023]
Abstract
Inefficient knock-in of transgene cargos limits the potential of cell-based medicines. In this study, we used a CRISPR nuclease that targets a site within an exon of an essential gene and designed a cargo template so that correct knock-in would retain essential gene function while also integrating the transgene(s) of interest. Cells with non-productive insertions and deletions would undergo negative selection. This technology, called SLEEK (SeLection by Essential-gene Exon Knock-in), achieved knock-in efficiencies of more than 90% in clinically relevant cell types without impacting long-term viability or expansion. SLEEK knock-in rates in T cells are more efficient than state-of-the-art TRAC knock-in with AAV6 and surpass more than 90% efficiency even with non-viral DNA cargos. As a clinical application, natural killer cells generated from induced pluripotent stem cells containing SLEEK knock-in of CD16 and mbIL-15 show substantially improved tumor killing and persistence in vivo.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Meng Wu
- Editas Medicine, Cambridge, MA, USA
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Zhao JJ, Sun XY, Tian SN, Zhao ZZ, Yin MD, Zhao M, Zhang F, Li SA, Yang ZX, Wen W, Cheng T, Gong A, Zhang JP, Zhang XB. Decoding the complexity of on-target integration: characterizing DNA insertions at the CRISPR-Cas9 targeted locus using nanopore sequencing. BMC Genomics 2024; 25:189. [PMID: 38368357 PMCID: PMC10874558 DOI: 10.1186/s12864-024-10050-6] [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: 06/05/2023] [Accepted: 01/24/2024] [Indexed: 02/19/2024] Open
Abstract
BACKGROUND CRISPR-Cas9 technology has advanced in vivo gene therapy for disorders like hemophilia A, notably through the successful targeted incorporation of the F8 gene into the Alb locus in hepatocytes, effectively curing this disorder in mice. However, thoroughly evaluating the safety and specificity of this therapy is essential. Our study introduces a novel methodology to analyze complex insertion sequences at the on-target edited locus, utilizing barcoded long-range PCR, CRISPR RNP-mediated deletion of unedited alleles, magnetic bead-based long amplicon enrichment, and nanopore sequencing. RESULTS We identified the expected F8 insertions and various fragment combinations resulting from the in vivo linearization of the double-cut plasmid donor. Notably, our research is the first to document insertions exceeding ten kbp. We also found that a small proportion of these insertions were derived from sources other than donor plasmids, including Cas9-sgRNA plasmids, genomic DNA fragments, and LINE-1 elements. CONCLUSIONS Our study presents a robust method for analyzing the complexity of on-target editing, particularly for in vivo long insertions, where donor template integration can be challenging. This work offers a new tool for quality control in gene editing outcomes and underscores the importance of detailed characterization of edited genomic sequences. Our findings have significant implications for enhancing the safety and effectiveness of CRISPR-Cas9 gene therapy in treating various disorders, including hemophilia A.
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Affiliation(s)
- Juan-Juan Zhao
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, National Clinical Research Center for Blood Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
| | - Xin-Yu Sun
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, National Clinical Research Center for Blood Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
| | | | - Zong-Ze Zhao
- College of Computer Science and Technology, China University of Petroleum (East China), Qingdao, 266000, China
| | - Meng-Di Yin
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, National Clinical Research Center for Blood Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
| | - Mei Zhao
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, National Clinical Research Center for Blood Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
| | - Feng Zhang
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, National Clinical Research Center for Blood Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
| | - Si-Ang Li
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, National Clinical Research Center for Blood Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
| | - Zhi-Xue Yang
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, National Clinical Research Center for Blood Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
| | - Wei Wen
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, National Clinical Research Center for Blood Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
| | - Tao Cheng
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, National Clinical Research Center for Blood Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China
- Tianjin Institutes of Health Science, Tianjin, 301600, China
| | - An Gong
- College of Computer Science and Technology, China University of Petroleum (East China), Qingdao, 266000, China.
| | - Jian-Ping Zhang
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, National Clinical Research Center for Blood Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China.
- Tianjin Institutes of Health Science, Tianjin, 301600, China.
| | - Xiao-Bing Zhang
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, National Clinical Research Center for Blood Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China.
- Tianjin Institutes of Health Science, Tianjin, 301600, China.
- Tianjin Medical University, Tianjin, China.
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Zhang X, Celic I, Mitchell H, Stuckert S, Vedula L, Han JS. Comprehensive profiling of L1 retrotransposons in mouse. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.13.566638. [PMID: 38014156 PMCID: PMC10680791 DOI: 10.1101/2023.11.13.566638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
L1 elements are retrotransposons currently active in mammals. Although L1s are typically silenced in most normal tissues, elevated L1 expression is associated with a variety of conditions, including cancer, aging, infertility, and neurological disease. These associations have raised interest in the mapping of human endogenous de novo L1 insertions, and a variety of methods have been developed for this purpose. Adapting these methods to mouse genomes would allow us to monitor endogenous in vivo L1 activity in controlled, experimental conditions using mouse disease models. Here we use a modified version of transposon insertion profiling, called nanoTIPseq, to selectively enrich young mouse L1s. By linking this amplification step with nanopore sequencing, we identified >95% annotated L1s from C57BL/6 genomic DNA using only 200,000 sequencing reads. In the process, we discovered 82 unannotated L1 insertions from a single C57BL/6 genome. Most of these unannotated L1s were near repetitive sequence and were not found with short-read TIPseq. We used nanoTIPseq on individual mouse breast cancer cells and were able to identify the annotated and unannotated L1s, as well as new insertions specific to individual cells, providing proof of principle for using nanoTIPseq to interrogate retrotransposition activity at the single cell level in vivo .
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Ivančić D, Mir-Pedrol J, Jaraba-Wallace J, Rafel N, Sanchez-Mejias A, Güell M. Author Correction: INSERT-seq enables high-resolution mapping of genomically integrated DNA using Nanopore sequencing. Genome Biol 2023; 24:137. [PMID: 37296438 DOI: 10.1186/s13059-023-02979-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023] Open
Affiliation(s)
- Dimitrije Ivančić
- Departament de Medicina i Ciències de La Vida (MELIS), Universitat Pompeu Fabra, Barcelona, Spain
- The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Júlia Mir-Pedrol
- Departament de Medicina i Ciències de La Vida (MELIS), Universitat Pompeu Fabra, Barcelona, Spain
| | - Jessica Jaraba-Wallace
- Departament de Medicina i Ciències de La Vida (MELIS), Universitat Pompeu Fabra, Barcelona, Spain
| | - Núria Rafel
- Departament de Medicina i Ciències de La Vida (MELIS), Universitat Pompeu Fabra, Barcelona, Spain
| | - Avencia Sanchez-Mejias
- Departament de Medicina i Ciències de La Vida (MELIS), Universitat Pompeu Fabra, Barcelona, Spain
| | - Marc Güell
- Departament de Medicina i Ciències de La Vida (MELIS), Universitat Pompeu Fabra, Barcelona, Spain.
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Han HJ, Kim DH, Baik JY. A splinkerette PCR-based genome walking technique for the identification of transgene integration sites in CHO cells. J Biotechnol 2023:S0168-1656(23)00105-0. [PMID: 37257509 DOI: 10.1016/j.jbiotec.2023.05.007] [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: 12/23/2022] [Revised: 05/02/2023] [Accepted: 05/28/2023] [Indexed: 06/02/2023]
Abstract
Identification of recombinant gene integrations sites in the Chinese hamster ovary (CHO) cell genome is increasingly important to assure monoclonality. While next-generation sequencing (NGS) is commonly used for the gene integration site analysis, it is a time-consuming and costly technique as it analyzes the entire genome. Hence, simple, easy, and inexpensive methods to analyze transgene insertion sites are necessary. To selectively capture the integration site of transgene in the CHO genome, we applied splinkerette-PCR (spPCR). SpPCR is an adaptor ligation-based method using splinkerette adaptors that have a stable hairpin loop. Restriction enzymes with high frequencies in the CHO genome were chosen using a Python script and used for the in vitro spPCR assay development. After testing on two CHO housekeeping genes with known loci, the spPCR-based genome walking technique was successfully applied to recombinant CHO cells to identify the transgene integration site. Finally, the comparison with NGS methods exhibited that the time and cost required for the analysis can be substantially reduced. Taken together, the established technique would aid the stable cell line development process by providing a rapid and cost-effective method for transgene integration site analysis.
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Affiliation(s)
- Hye-Jin Han
- Department of Biological Sciences and Bioengineering, Inha University, Incheon22212, Republic of Korea
| | - Dae Hoon Kim
- Department of Biological Sciences and Bioengineering, Inha University, Incheon22212, Republic of Korea
| | - Jong Youn Baik
- Department of Biological Sciences and Bioengineering, Inha University, Incheon22212, Republic of Korea.
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