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Sagini MN, Zepp M, Eyol E, Ali DM, Gromova S, Dahlmann M, Behrens D, Groeschel C, Tischmeier L, Hoffmann J, Berger MR, Forssmann WG. EPI-X4, a CXCR4 antagonist inhibits tumor growth in pancreatic cancer and lymphoma models. Peptides 2024; 175:171111. [PMID: 38036098 DOI: 10.1016/j.peptides.2023.171111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 10/20/2023] [Accepted: 10/25/2023] [Indexed: 12/02/2023]
Abstract
Endogenous peptide inhibitor for CXCR4 (EPI-X4) is a CXCR4 antagonist with potential for cancer therapy. It is a processed fragment of serum albumin from the hemofiltrate of dialysis patients. This study reports the efficacy of fifteen EPI-X4 derivatives in pancreatic cancer and lymphoma models. In vitro, the peptides were investigated for antiproliferation (cytotoxicity) by MTT assay. The mRNA expression for CXCR4 and CXCL12 was determined by RT-PCR, chip array and RNA sequencing. Chip array analysis yielded 634 genes associated with CXCR4/CXCL12 signaling. About 21% of these genes correlated with metastasis in the context of cell motility, proliferation, and survival. Expression levels of these genes were altered in pancreatic cancer (36%), lymphoma models (53%) and in patients' data (58%). EPI-X4 derivatives failed to inhibit cell proliferation due to low expression of CXCR4 in vitro, but inhibited tumor growth in the bioassays with significant efficacy. In the pancreatic cancer model, EPI-X4a, f and k inhibited mean tumor growth by > 50% and even caused complete remissions. In the lymphoma model, EPI-X4b, n and p inhibited mean tumor growth by > 70% and caused stable disease. Given the non-toxic and non-immunogenic properties of EPI-X4, these findings underscore its status as a promising therapy of pancreatic cancer and lymphoma and warrant further studies. SIMPLE SUMMARY: This study examined the value of chemokine receptor CXCR4 as an antineoplastic target for the endogenous peptide inhibitor of CXCR4 (EPI-X4), a 12-meric peptide derived from serum albumin. EPI-X4 inhibits CXCR4 interaction with its natural ligand, CXCL12 (SDF1). Therefore, malignancies (including pancreatic cancer and lymphoma) that depend on the CXCR4/CXCL12 pathway for progression can be targeted with EPI-X4. Of 634 genes that were linked to the CXCR4/CXCL12 pathway, 21% were associated with metastasis. In cultured human Suit2-007 pancreatic cancer cells, CXCR4 showed low to undetectable expression, which was why EPI-X4 did not inhibit pancreatic cancer cell proliferation. These findings were different in vivo, where CXCR4 was highly expressed and EPI-X4 inhibited tumor growth in rodents harboring pancreatic cancer or lymphoma. In the pancreatic cancer model, EPI-X4 derivatives a, f and k caused complete remissions, while in lymphomas EPI-X4 derivatives b, n and p caused stable disease.
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Affiliation(s)
- Micah N Sagini
- Toxicology and Chemotherapy Unit, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Michael Zepp
- Toxicology and Chemotherapy Unit, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Ergül Eyol
- Toxicology and Chemotherapy Unit, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Doaa M Ali
- Toxicology and Chemotherapy Unit, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Svetlana Gromova
- EPO, Experimental Pharmacology & Oncology Berlin-Buch GmbH, Germany
| | - Mathias Dahlmann
- EPO, Experimental Pharmacology & Oncology Berlin-Buch GmbH, Germany
| | - Diana Behrens
- EPO, Experimental Pharmacology & Oncology Berlin-Buch GmbH, Germany
| | - Christian Groeschel
- NeoPep Pharma GmbH & Co. KG., Hannover, Germany and Hannover Medical School, Department of Internal Medicine, Germany
| | - Linus Tischmeier
- NeoPep Pharma GmbH & Co. KG., Hannover, Germany and Hannover Medical School, Department of Internal Medicine, Germany
| | - Jens Hoffmann
- EPO, Experimental Pharmacology & Oncology Berlin-Buch GmbH, Germany
| | - Martin R Berger
- Toxicology and Chemotherapy Unit, German Cancer Research Centre (DKFZ), Heidelberg, Germany.
| | - Wolf-Georg Forssmann
- NeoPep Pharma GmbH & Co. KG., Hannover, Germany and Hannover Medical School, Department of Internal Medicine, Germany.
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2
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Bozza M, Green EW, Espinet E, De Roia A, Klein C, Vogel V, Offringa R, Williams JA, Sprick M, Harbottle RP. Novel Non-integrating DNA Nano-S/MAR Vectors Restore Gene Function in Isogenic Patient-Derived Pancreatic Tumor Models. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 17:957-968. [PMID: 32420409 PMCID: PMC7218229 DOI: 10.1016/j.omtm.2020.04.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 04/22/2020] [Indexed: 12/22/2022]
Abstract
We describe herein non-integrating minimally sized nano-S/MAR DNA vectors, which can be used to genetically modify dividing cells in place of integrating vectors. They represent a unique genetic tool, which avoids vector-mediated damage. Previous work has shown that DNA vectors comprising a mammalian S/MAR element can provide persistent mitotic stability over hundreds of cell divisions, resisting epigenetic silencing and thereby allowing sustained transgene expression. The composition of the original S/MAR vectors does present some inherent limitations that can provoke cellular toxicity. Herein, we present a new system, the nano-S/MAR, which drives higher transgene expression and has improved efficiency of establishment, due to the minimal impact on cellular processes and perturbation of the endogenous transcriptome. We show that these features enable the hitherto challenging genetic modification of patient-derived cells to stably restore the tumor suppressor gene SMAD4 to a patient-derived SMAD4 knockout pancreatic cancer line. Nano-S/MAR modification does not alter the molecular or phenotypic integrity of the patient-derived cells in cell culture and xenograft mouse models. In conclusion, we show that these DNA vectors can be used to persistently modify a range of cells, providing sustained transgene expression while avoiding the risks of insertional mutagenesis and other vector-mediated toxicity.
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Affiliation(s)
- Matthias Bozza
- DNA Vector Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 242, 69120 Heidelberg, Germany
| | - Edward W Green
- Neuroimmunology and Brain Tumor Immunology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Elisa Espinet
- Division of Stem Cells and Cancer, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Alice De Roia
- DNA Vector Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 242, 69120 Heidelberg, Germany
| | - Corinna Klein
- Stem Cells and Metastasis, Hi-Stem Heidelberg, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Vanessa Vogel
- Stem Cells and Metastasis, Hi-Stem Heidelberg, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Rienk Offringa
- Molecular Oncology of Gastrointestinal Tumors, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | | | - Martin Sprick
- Stem Cells and Metastasis, Hi-Stem Heidelberg, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Richard P Harbottle
- DNA Vector Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 242, 69120 Heidelberg, Germany
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3
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Sánchez-Hernández S, Gutierrez-Guerrero A, Martín-Guerra R, Cortijo-Gutierrez M, Tristán-Manzano M, Rodriguez-Perales S, Sanchez L, Garcia-Perez JL, Chato-Astrain J, Fernandez-Valades R, Carrillo-Galvez AB, Anderson P, Montes R, Real PJ, Martin F, Benabdellah K. The IS2 Element Improves Transcription Efficiency of Integration-Deficient Lentiviral Vector Episomes. MOLECULAR THERAPY-NUCLEIC ACIDS 2018; 13:16-28. [PMID: 30227274 PMCID: PMC6141704 DOI: 10.1016/j.omtn.2018.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 07/02/2018] [Accepted: 08/14/2018] [Indexed: 02/06/2023]
Abstract
Integration-defective lentiviral vectors (IDLVs) have become an important alternative tool for gene therapy applications and basic research. Unfortunately, IDLVs show lower transgene expression as compared to their integrating counterparts. In this study, we aimed to improve the expression levels of IDLVs by inserting the IS2 element, which harbors SARs and HS4 sequences, into their LTRs (SE-IS2-IDLVs). Contrary to our expectations, the presence of the IS2 element did not abrogate epigenetic silencing by histone deacetylases. In addition, the IS2 element reduced episome levels in IDLV-transduced cells. Interestingly, despite these negative effects, SE-IS2-IDLVs outperformed SE-IDLVs in terms of percentage and expression levels of the transgene in several cell lines, including neurons, neuronal progenitor cells, and induced pluripotent stem cells. We estimated that the IS2 element enhances the transcriptional activity of IDLV LTR circles 6- to 7-fold. The final effect the IS2 element in IDLVs will greatly depend on the target cell and the balance between the negative versus the positive effects of the IS2 element in each cell type. The better performance of SE-IS2-IDLVs was not due to improved stability or differences in the proportions of 1-LTR versus 2-LTR circles but probably to a re-positioning of IS2-episomes into transcriptionally active regions.
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Affiliation(s)
- Sabina Sánchez-Hernández
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Alejandra Gutierrez-Guerrero
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Rocío Martín-Guerra
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Marina Cortijo-Gutierrez
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - María Tristán-Manzano
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Sandra Rodriguez-Perales
- Molecular Cytogenetics and Genome Editing Unit, Human Cancer Genetics Department, CNIO, Melchor Fernandez Almagro 3, 28029 Madrid, Spain
| | - Laura Sanchez
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Jose Luis Garcia-Perez
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Jesus Chato-Astrain
- Department of Histology, Tissue Engineering Group, University of Granada, Granada, Spain
| | - Ricardo Fernandez-Valades
- Pediatric Surgery Department, University Hospital "Virgen de las Nieves," Avda. Fuerzas Armadas 2, 18014 Granada, Spain
| | - Ana Belén Carrillo-Galvez
- Oncology Department, GENYO, Centre for Genomics and Oncology, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Per Anderson
- LentiStem Biotech, GENYO, Avda. de la Ilustración 114, 18016 PTS Granada, Spain; Oncology Department, GENYO, Centre for Genomics and Oncology, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Rosa Montes
- Oncology Department, GENYO, Centre for Genomics and Oncology, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Pedro J Real
- Oncology Department, GENYO, Centre for Genomics and Oncology, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; Departament of Biochemistry and Molecular Biology I, University of Granada, Granada, Spain
| | - Francisco Martin
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; LentiStem Biotech, GENYO, Avda. de la Ilustración 114, 18016 PTS Granada, Spain.
| | - Karim Benabdellah
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; LentiStem Biotech, GENYO, Avda. de la Ilustración 114, 18016 PTS Granada, Spain.
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4
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Hagedorn C, Gogol-Döring A, Schreiber S, Epplen JT, Lipps HJ. Genome-wide profiling of S/MAR-based replicon contact sites. Nucleic Acids Res 2017; 45:7841-7854. [PMID: 28609784 PMCID: PMC5570033 DOI: 10.1093/nar/gkx522] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 06/05/2017] [Indexed: 11/14/2022] Open
Abstract
Autonomously replicating vectors represent a simple and versatile model system for genetic modifications, but their localization in the nucleus and effect on endogenous gene expression is largely unknown. Using circular chromosome conformation capture we mapped genomic contact sites of S/MAR-based replicons in HeLa cells. The influence of cis-active sequences on genomic localization was assessed using replicons containing either an insulator sequence or an intron. While the original and the insulator-containing replicons displayed distinct contact sites, the intron-containing replicon showed a rather broad genomic contact pattern. Our results indicate a preference for certain chromatin structures and a rather non-dynamic behaviour during mitosis. Independent of inserted cis-active elements established vector molecules reside preferentially within actively transcribed regions, especially within promoter sequences and transcription start sites. However, transcriptome analyses revealed that established S/MAR-based replicons do not alter gene expression profiles of host genome. Knowledge of preferred contact sites of exogenous DNA, e.g. viral or non-viral episomes, contribute to our understanding of episome behaviour in the nucleus and can be used for vector improvement and guiding of DNA sequences to specific subnuclear sites.
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Affiliation(s)
- Claudia Hagedorn
- University of Witten/Herdecke, ZBAF, Institute of Cell Biology, Stockumer Strasse 10, 58453 Witten, Germany
| | - Andreas Gogol-Döring
- Technische Hochschule Mittelhessen (University of Applied Sciences), Department of Bioinformatics, Wiesenstrasse 14, 35390 Gießen, Germany
| | - Sabrina Schreiber
- Department of Human Genetics, Ruhr-University, Universitätsstraße 150, 44801 Bochum, Germany
| | - Jörg T Epplen
- University of Witten/Herdecke, ZBAF, Institute of Cell Biology, Stockumer Strasse 10, 58453 Witten, Germany.,Department of Human Genetics, Ruhr-University, Universitätsstraße 150, 44801 Bochum, Germany
| | - Hans J Lipps
- University of Witten/Herdecke, ZBAF, Institute of Cell Biology, Stockumer Strasse 10, 58453 Witten, Germany
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5
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Chira S, Jackson CS, Oprea I, Ozturk F, Pepper MS, Diaconu I, Braicu C, Raduly LZ, Calin GA, Berindan-Neagoe I. Progresses towards safe and efficient gene therapy vectors. Oncotarget 2016; 6:30675-703. [PMID: 26362400 PMCID: PMC4741561 DOI: 10.18632/oncotarget.5169] [Citation(s) in RCA: 134] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/22/2015] [Indexed: 12/11/2022] Open
Abstract
The emergence of genetic engineering at the beginning of the 1970′s opened the era of biomedical technologies, which aims to improve human health using genetic manipulation techniques in a clinical context. Gene therapy represents an innovating and appealing strategy for treatment of human diseases, which utilizes vehicles or vectors for delivering therapeutic genes into the patients' body. However, a few past unsuccessful events that negatively marked the beginning of gene therapy resulted in the need for further studies regarding the design and biology of gene therapy vectors, so that this innovating treatment approach can successfully move from bench to bedside. In this paper, we review the major gene delivery vectors and recent improvements made in their design meant to overcome the issues that commonly arise with the use of gene therapy vectors. At the end of the manuscript, we summarized the main advantages and disadvantages of common gene therapy vectors and we discuss possible future directions for potential therapeutic vectors.
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Affiliation(s)
- Sergiu Chira
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, University of Medicine and Pharmacy "Iuliu Haţieganu", Cluj Napoca, Romania
| | - Carlo S Jackson
- Department of Immunology and Institute for Cellular and Molecular Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Iulian Oprea
- Department of Oncology and Pathology, Cancer Center Karolinska, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Ferhat Ozturk
- Department of Molecular Biology and Genetics, Canik Başari University, Samsun, Turkey
| | - Michael S Pepper
- Department of Immunology and Institute for Cellular and Molecular Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | | | - Cornelia Braicu
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, University of Medicine and Pharmacy "Iuliu Haţieganu", Cluj Napoca, Romania
| | - Lajos-Zsolt Raduly
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, University of Medicine and Pharmacy "Iuliu Haţieganu", Cluj Napoca, Romania.,Department of Physiopathology, Faculty of Veterinary Medicine, University of Agricultural Science and Veterinary Medicine, Cluj Napoca, Romania
| | - George A Calin
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,Center for RNA Interference and Non-Coding RNAs, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Ioana Berindan-Neagoe
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, University of Medicine and Pharmacy "Iuliu Haţieganu", Cluj Napoca, Romania.,Department of Immunology, University of Medicine and Pharmacy "Iuliu Haţieganu", Cluj Napoca, Romania.,Department of Functional Genomics and Experimental Pathology, Oncological Institute "Prof. Dr. Ion Chiricuţă", Cluj Napoca, Romania.,Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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6
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Kudsiova L, Welser K, Campbell F, Mohammadi A, Dawson N, Cui L, Hailes HC, Lawrence MJ, Tabor AB. Delivery of siRNA using ternary complexes containing branched cationic peptides: the role of peptide sequence, branching and targeting. MOLECULAR BIOSYSTEMS 2016; 12:934-51. [PMID: 26794416 DOI: 10.1039/c5mb00754b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ternary nanocomplexes, composed of bifunctional cationic peptides, lipids and siRNA, as delivery vehicles for siRNA have been investigated. The study is the first to determine the optimal sequence and architecture of the bifunctional cationic peptide used for siRNA packaging and delivery using lipopolyplexes. Specifically three series of cationic peptides of differing sequence, degrees of branching and cell-targeting sequences were co-formulated with siRNA and vesicles prepared from a 1 : 1 molar ratio of the cationic lipid DOTMA and the helper lipid, DOPE. The level of siRNA knockdown achieved in the human alveolar cell line, A549-luc cells, in both reduced serum and in serum supplemented media was evaluated, and the results correlated to the nanocomplex structure (established using a range of physico-chemical tools, namely small angle neutron scattering, transmission electron microscopy, dynamic light scattering and zeta potential measurement); the conformational properties of each component (circular dichroism); the degree of protection of the siRNA in the lipopolyplex (using gel shift assays) and to the cellular uptake, localisation and toxicity of the nanocomplexes (confocal microscopy). Although the size, charge, structure and stability of the various lipopolyplexes were broadly similar, it was clear that lipopolyplexes formulated from branched peptides containing His-Lys sequences perform best as siRNA delivery agents in serum, with protection of the siRNA in serum balanced against efficient release of the siRNA into the cytoplasm of the cell.
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Affiliation(s)
- Laila Kudsiova
- Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, Waterloo Campus, London SE1 9NH, UK
| | - Katharina Welser
- Department of Chemistry, University College London, Christopher Ingold Laboratories, 20, Gordon Street, London WC1H 0AJ, UK.
| | - Frederick Campbell
- Department of Chemistry, University College London, Christopher Ingold Laboratories, 20, Gordon Street, London WC1H 0AJ, UK.
| | - Atefeh Mohammadi
- Department of Chemistry, University College London, Christopher Ingold Laboratories, 20, Gordon Street, London WC1H 0AJ, UK.
| | - Natalie Dawson
- Department of Chemistry, University College London, Christopher Ingold Laboratories, 20, Gordon Street, London WC1H 0AJ, UK.
| | - Lili Cui
- Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, Waterloo Campus, London SE1 9NH, UK
| | - Helen C Hailes
- Department of Chemistry, University College London, Christopher Ingold Laboratories, 20, Gordon Street, London WC1H 0AJ, UK.
| | - M Jayne Lawrence
- Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, Waterloo Campus, London SE1 9NH, UK
| | - Alethea B Tabor
- Department of Chemistry, University College London, Christopher Ingold Laboratories, 20, Gordon Street, London WC1H 0AJ, UK.
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7
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Wong SP, Argyros O, Harbottle RP. Sustained expression from DNA vectors. ADVANCES IN GENETICS 2014; 89:113-152. [PMID: 25620010 DOI: 10.1016/bs.adgen.2014.11.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
DNA vectors have the potential to become powerful medical tools for treatment of human disease. The human body has, however, developed a range of defensive strategies to detect and silence foreign or misplaced DNA, which is more typically encountered during infection or chromosomal damage. A clinically relevant human gene therapy vector must overcome or avoid these protections whilst delivering sustained levels of therapeutic gene product without compromising the vitality of the recipient host. Many non-viral DNA vectors trigger these defense mechanisms and are subsequently destroyed or rendered silent. Thus, without modification or considered design, the clinical utility of a typical DNA vector is fundamentally limited due to the transient nature of its transgene expression. The development of safe and persistently expressing DNA vectors is a crucial prerequisite for its successful clinical application and subsequently remains, therefore, one of the main strategic tasks of non-viral gene therapy research. In this chapter we will describe our current understanding of the mechanisms that can destroy or silence DNA vectors and discuss strategies, which have been utilized to improve their sustenance and the level and duration of their transgene expression.
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Affiliation(s)
- Suet Ping Wong
- Leukocyte Biology Section, National Heart & Lung Institute, Imperial College London, London, UK
| | - Orestis Argyros
- Division of Pharmacology-Pharmacotechnology, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Richard P Harbottle
- DNA Vector Research, German Cancer Research Centre (DKFZ), Heidelberg, Germany
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8
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Development and validation of non-integrative, self-limited, and replicating minicircles for safe reporter gene imaging of cell-based therapies. PLoS One 2013; 8:e73138. [PMID: 24015294 PMCID: PMC3756008 DOI: 10.1371/journal.pone.0073138] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 07/24/2013] [Indexed: 12/24/2022] Open
Abstract
Reporter gene (RG) imaging of cell-based therapies provides a direct readout of therapeutic efficacy by assessing the fate of implanted cells. To permit long-term cellular imaging, RGs are traditionally required to be integrated into the cellular genome. This poses a potential safety risk and regulatory bottleneck for clinical translation as integration can lead to cellular transformation. To address this issue, we have developed non-integrative, replicating minicircles (MCs) as an alternative platform for safer monitoring of cells in living subjects. We developed both plasmids and minicircles containing the scaffold/matrix attachment regions (S/MAR) of the human interferon-beta gene, driven by the CMV promoter, and expressing the bioluminescence RG firefly luciferase. Constructs were transfected into breast cancer cells, and expanded S/MAR minicircle clones showed luciferase signal for greater than 3 months in culture and minicircles remained as episomes. Importantly, luciferase activity in clonal populations was slowly lost over time and this corresponded to a loss of episome, providing a way to reversibly label cells. To monitor cell proliferation in vivo, 1.5×106 cells carrying the S/MAR minicircle were implanted subcutaneously into mice (n = 5) and as tumors developed significantly more bioluminescence signal was noted at day 35 and 43 compared to day 7 post-implant (p<0.05). To our knowledge, this is the first work examining the use of episomal, self-limited, replicating minicircles to track the proliferation of cells using non-invasive imaging in living subjects. Continued development of S/MAR minicircles will provide a broadly applicable vector platform amenable with any of the numerous RG technologies available to allow therapeutic cell fate to be assessed in individual patients, and to achieve this without the need to manipulate the cell's genome so that safety concerns are minimized. This will lead to safe tools to assess treatment response at earlier time points and improve the precision of cell-based therapies.
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9
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Genetic modification of dividing cells using episomally maintained S/MAR DNA vectors. MOLECULAR THERAPY. NUCLEIC ACIDS 2013; 2:e115. [PMID: 23941867 PMCID: PMC3759738 DOI: 10.1038/mtna.2013.40] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 05/28/2013] [Indexed: 01/23/2023]
Abstract
The development of episomally maintained DNA vectors to genetically modify dividing cells efficiently and stably, without the risk of integration-mediated genotoxicity, should prove to be a valuable tool in genetic research. In this study, we demonstrate the utility of Scaffold/Matrix Attachment Region (S/MAR) DNA vectors to model the restoration of a functional wild-type copy of the gene folliculin (FLCN) implicated in the renal cancer Birt-Hogg-Dubé (BHD). Inactivation of FLCN has been shown to be involved in the development of sporadic renal neoplasia in BHD. S/MAR-modified BHD tumor cells (named UOK257-FS) show restored stable FLCN expression and have normalized downstream TGFβ signals. We demonstrate that UOK257-FS cells show a reduced growth rate in vitro and suppression of xenograft tumor development in vivo, compared with the original FLCN-null UOK257 cell line. In addition, we demonstrate that mTOR signaling in serum-starved FLCN-restored cells is differentially regulated compared with the FLCN-deficient cell. The novel UOK257-FS cell line will be useful for studying the signaling pathways affected in BHD pathogenesis. Significantly, this study demonstrates the suitability of S/MAR vectors to successfully model the functional expression of a therapeutic gene in a cancer cell line and will aid the identification of novel cancer markers for diagnosis and therapy.
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