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Botor M, Fus-Kujawa A, Uroczynska M, Stepien KL, Galicka A, Gawron K, Sieron AL. Osteogenesis Imperfecta: Current and Prospective Therapies. Biomolecules 2021; 11:biom11101493. [PMID: 34680126 PMCID: PMC8533546 DOI: 10.3390/biom11101493] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/04/2021] [Accepted: 10/06/2021] [Indexed: 12/20/2022] Open
Abstract
Osteogenesis Imperfecta (OI) is a group of connective tissue disorders with a broad range of phenotypes characterized primarily by bone fragility. The prevalence of OI ranges from about 1:15,000 to 1:20,000 births. Five types of the disease are commonly distinguished, ranging from a mild (type I) to a lethal one (type II). Types III and IV are severe forms allowing survival after the neonatal period, while type V is characterized by a mild to moderate phenotype with calcification of interosseous membranes. In most cases, there is a reduction in the production of normal type I collagen (col I) or the synthesis of abnormal collagen as a result of mutations in col I genes. Moreover, mutations in genes involved in col I synthesis and processing as well as in osteoblast differentiation have been reported. The currently available treatments try to prevent fractures, control symptoms and increase bone mass. Commonly used medications in OI treatment are bisphosphonates, Denosumab, synthetic parathyroid hormone and growth hormone for children therapy. The main disadvantages of these therapies are their relatively weak effectiveness, lack of effects in some patients or cytotoxic side effects. Experimental approaches, particularly those based on stem cell transplantation and genetic engineering, seem to be promising to improve the therapeutic effects of OI.
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Affiliation(s)
- Malwina Botor
- Department of Molecular Biology and Genetics, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medykow 18, 40-752 Katowice, Poland; (A.F.-K.); (M.U.); (K.L.S.); (K.G.); (A.L.S.)
- Correspondence:
| | - Agnieszka Fus-Kujawa
- Department of Molecular Biology and Genetics, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medykow 18, 40-752 Katowice, Poland; (A.F.-K.); (M.U.); (K.L.S.); (K.G.); (A.L.S.)
| | - Marta Uroczynska
- Department of Molecular Biology and Genetics, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medykow 18, 40-752 Katowice, Poland; (A.F.-K.); (M.U.); (K.L.S.); (K.G.); (A.L.S.)
| | - Karolina L. Stepien
- Department of Molecular Biology and Genetics, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medykow 18, 40-752 Katowice, Poland; (A.F.-K.); (M.U.); (K.L.S.); (K.G.); (A.L.S.)
| | - Anna Galicka
- Department of Medical Chemistry, Medical University of Bialystok, Mickiewicza 2A, 15-222 Bialystok, Poland;
| | - Katarzyna Gawron
- Department of Molecular Biology and Genetics, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medykow 18, 40-752 Katowice, Poland; (A.F.-K.); (M.U.); (K.L.S.); (K.G.); (A.L.S.)
| | - Aleksander L. Sieron
- Department of Molecular Biology and Genetics, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medykow 18, 40-752 Katowice, Poland; (A.F.-K.); (M.U.); (K.L.S.); (K.G.); (A.L.S.)
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2
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Geisinger JM, Stearns T. CRISPR/Cas9 treatment causes extended TP53-dependent cell cycle arrest in human cells. Nucleic Acids Res 2020; 48:9067-9081. [PMID: 32687165 PMCID: PMC7498335 DOI: 10.1093/nar/gkaa603] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 07/02/2020] [Accepted: 07/07/2020] [Indexed: 12/30/2022] Open
Abstract
While the mechanism of CRISPR/Cas9 cleavage is understood, the basis for the large variation in mutant recovery for a given target sequence between cell lines is much less clear. We hypothesized that this variation may be due to differences in how the DNA damage response affects cell cycle progression. We used incorporation of EdU as a marker of cell cycle progression to analyze the response of several human cell lines to CRISPR/Cas9 treatment with a single guide directed to a unique locus. Cell lines with functionally wild-type TP53 exhibited higher levels of cell cycle arrest compared to lines without. Chemical inhibition of TP53 protein combined with TP53 and RB1 transcript silencing alleviated induced arrest in TP53+/+ cells. Using dCas9, we determined this arrest is driven in part by Cas9 binding to DNA. Additionally, wild-type Cas9 induced fewer 53BP1 foci in TP53+/+ cells compared to TP53−/− cells and DD-Cas9, suggesting that differences in break sensing are responsible for cell cycle arrest variation. We conclude that CRISPR/Cas9 treatment induces a cell cycle arrest dependent on functional TP53 as well as Cas9 DNA binding and cleavage. Our findings suggest that transient inhibition of TP53 may increase genome editing recovery in primary and TP53+/+ cell lines.
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Affiliation(s)
| | - Tim Stearns
- Department of Biology, Stanford University, Stanford, CA 94305, USA.,Department of Genetics, Stanford University Medical School, Stanford, CA 94305, USA
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3
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Guha TK, Calos MP. Nucleofection of phiC31 Integrase Protein Mediates Sequence-Specific Genomic Integration in Human Cells. J Mol Biol 2020; 432:3950-3955. [PMID: 32339531 DOI: 10.1016/j.jmb.2020.04.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/17/2020] [Accepted: 04/20/2020] [Indexed: 10/24/2022]
Abstract
The phage-derived phiC31 integrase is a useful tool for mediating sequence-specific genomic integration in mammalian cells, recombining donor plasmids bearing the attB recognition site with introduced genomic attP sites or endogeneous pseudo-attP sites having partial identity to attP. In most prior studies, phiC31 integrase has been introduced as plasmid DNA or mRNA. The current report examines whether phiC31 integrase functions efficiently in mammalian cells when co-nucleofected as a purified protein, along with attB-containing donor plasmids or PCR fragments. We describe preparation of phiC31 integrase protein and evidence that it can mediate genomic integration in human 293 cells, including PCR evidence for integration at an endogenous pseudo-attP site. This work demonstrates for the first time the ability of 605- and 613-amino-acid versions of phiC31 integrase protein to mediate efficient, site-specific integration into the genome of human cells when co-nucleofected with full-sizedattB-containing donor plasmids or linear 2.5-kb PCR fragments. This protein-mediated approach may be especially useful for integration of exogenous sequences into valuable therapeutic target cells, such as hematopoietic stem cells or T cells, that are sensitive to introduced DNA.
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Affiliation(s)
- Tuhin K Guha
- Department of Genetics, Stanford University School of Medicine, Stanford, 94305-5120 CA, USA
| | - Michele P Calos
- Department of Genetics, Stanford University School of Medicine, Stanford, 94305-5120 CA, USA.
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4
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Assumpção PB, Canelas EC, Ramos AC, Anaissi A, Acioli JF, Ishak G, Santos S, Demachki S, Assumpção P. Lymph nodes may be a source for immunetherapy in gastric cancer. Oncotarget 2020; 11:1729-1736. [PMID: 32477462 PMCID: PMC7233812 DOI: 10.18632/oncotarget.27578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/10/2020] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND adoptive immunotherapy is a promising cancer therapy. Immune cells are capable of recognizing and destroying cancer cells and represent a powerful strategy, however, this approach remains technically complicated, due to the need to select and isolate immune cells from these, present cancer antigens to those cells, expanding and reinjecting them. Lymph nodes recovered during gastric cancer surgery may represent an option for immunotherapy, since they harbor an enormous amount of immune cells, which have already been presented to cancer antigens. The advantage of selecting only cancer-negative lymph has not been determined yet. The status of immune checkpoints in the immune cells within the lymph nodes was analyzed in order to try to solve this problem. MATERIALS AND METHODS Tissue microarrays were constructed and automated immunostaining for PD-1 and PD-L1 was performed on 143 lymph nodes from 70 patients with gastric adenocarcinoma. RESULTS In positive nodes, PD-L1 was only positivity in cancer cells (6%) and PD-1 was positive for B lymphocytes (60%), T lymphocytes (70%) and one case in cancer cells (2.5%). In negative nodes, most cases were positive for PD-1 in B (73.1%) and T (71.65%) lymphocytes. CONCLUSIONS Expression of PD-1 and PD-L1 in gastric cancer lymph nodes was demonstrated for the first time. PD-1 is expressed in positive and negative nodes, which could activate the PD-1 pathway. Lymphocytes from tumor-free lymph nodes were negative for PD-L1, and this might represent an advantage for selecting these lymph nodes as a potential source of immune cells for adoptive immunotherapy.
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Affiliation(s)
- Paula Baraúna Assumpção
- Laboratório Genética Humana e Médica, Universidade Federal do Pará, Belém-PA, Brasil.,Núcleo de Pesquisas em Oncologia, Hospital Universitário João de Barros Barreto, Belém-PA, Brasil
| | - Erika Couto Canelas
- Núcleo de Pesquisas em Oncologia, Hospital Universitário João de Barros Barreto, Belém-PA, Brasil
| | - Aline Cruz Ramos
- Núcleo de Pesquisas em Oncologia, Hospital Universitário João de Barros Barreto, Belém-PA, Brasil
| | - Ana Anaissi
- Núcleo de Pesquisas em Oncologia, Hospital Universitário João de Barros Barreto, Belém-PA, Brasil.,Instituto de Ciências da Saúde, Universidade Federal do Pará, Belém-PA, Brasil
| | - João Felipe Acioli
- Núcleo de Pesquisas em Oncologia, Hospital Universitário João de Barros Barreto, Belém-PA, Brasil.,Serviço de Cirurgia do Hospital Universitário João do Barros Barreto, Belém-PA, Brasil
| | - Geraldo Ishak
- Núcleo de Pesquisas em Oncologia, Hospital Universitário João de Barros Barreto, Belém-PA, Brasil.,Serviço de Cirurgia do Hospital Universitário João do Barros Barreto, Belém-PA, Brasil
| | - Sidney Santos
- Laboratório Genética Humana e Médica, Universidade Federal do Pará, Belém-PA, Brasil.,Núcleo de Pesquisas em Oncologia, Hospital Universitário João de Barros Barreto, Belém-PA, Brasil
| | - Samia Demachki
- Núcleo de Pesquisas em Oncologia, Hospital Universitário João de Barros Barreto, Belém-PA, Brasil.,Instituto de Ciências da Saúde, Universidade Federal do Pará, Belém-PA, Brasil
| | - Paulo Assumpção
- Núcleo de Pesquisas em Oncologia, Hospital Universitário João de Barros Barreto, Belém-PA, Brasil
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5
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Ornell KJ, Coburn JM. Developing preclinical models of neuroblastoma: driving therapeutic testing. BMC Biomed Eng 2019; 1:33. [PMID: 32903387 PMCID: PMC7422585 DOI: 10.1186/s42490-019-0034-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 11/19/2019] [Indexed: 12/14/2022] Open
Abstract
Despite advances in cancer therapeutics, particularly in the area of immuno-oncology, successful treatment of neuroblastoma (NB) remains a challenge. NB is the most common cancer in infants under 1 year of age, and accounts for approximately 10% of all pediatric cancers. Currently, children with high-risk NB exhibit a survival rate of 40–50%. The heterogeneous nature of NB makes development of effective therapeutic strategies challenging. Many preclinical models attempt to mimic the tumor phenotype and tumor microenvironment. In vivo mouse models, in the form of genetic, syngeneic, and xenograft mice, are advantageous as they replicated the complex tumor-stroma interactions and represent the gold standard for preclinical therapeutic testing. Traditional in vitro models, while high throughput, exhibit many limitations. The emergence of new tissue engineered models has the potential to bridge the gap between in vitro and in vivo models for therapeutic testing. Therapeutics continue to evolve from traditional cytotoxic chemotherapies to biologically targeted therapies. These therapeutics act on both the tumor cells and other cells within the tumor microenvironment, making development of preclinical models that accurately reflect tumor heterogeneity more important than ever. In this review, we will discuss current in vitro and in vivo preclinical testing models, and their potential applications to therapeutic development.
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Affiliation(s)
- Kimberly J Ornell
- Department of Biomedical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01605 USA
| | - Jeannine M Coburn
- Department of Biomedical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01605 USA
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6
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Plasmid-Mediated Gene Therapy in Mouse Models of Limb Girdle Muscular Dystrophy. Mol Ther Methods Clin Dev 2019; 15:294-304. [PMID: 31890729 PMCID: PMC6923511 DOI: 10.1016/j.omtm.2019.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/09/2019] [Indexed: 11/30/2022]
Abstract
We delivered plasmid DNA encoding therapeutic genes to the muscles of mouse models of limb girdle muscular dystrophy (LGMD) 2A, 2B, and 2D, deficient in calpain3, dysferlin, and alpha-sarcoglycan, respectively. We also delivered the human follistatin gene, which has the potential to increase therapeutic benefit. After intramuscular injection of DNA, electroporation was applied to enhance delivery to muscle fibers. When plasmids encoding the human calpain3 or dysferlin cDNA sequences were injected into quadriceps muscles of LGMD2A and LGMD2B mouse models, respectively, in 3-month studies, robust levels of calpain3 and dysferlin proteins were detected. We observed a statistically significant decrease in Evans blue dye penetration in LGMD2B mouse muscles after delivery of the dysferlin gene, consistent with repair of the muscle membrane defect in these mice. The therapeutic value of delivery of the genes for alpha-sarcoglycan and follistatin was documented by significant drops in Evans blue dye penetration in gastrocnemius muscles of LGMD2D mice. These results indicated for the first time that a combined gene therapy involving both alpha-sarcoglycan and follistatin would be valuable for LGMD2D patients. We suggest that this non-viral gene delivery method should be explored for its translational potential in patients.
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7
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Waldman SA, Terzic A. Health Care Evolves From Reactive to Proactive. Clin Pharmacol Ther 2019; 105:10-13. [PMID: 30597564 DOI: 10.1002/cpt.1295] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Scott A Waldman
- Division of Clinical Pharmacology, Department of Pharmacology and Experimental Therapeutics, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Andre Terzic
- Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota, USA
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8
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Goswami R, Subramanian G, Silayeva L, Newkirk I, Doctor D, Chawla K, Chattopadhyay S, Chandra D, Chilukuri N, Betapudi V. Gene Therapy Leaves a Vicious Cycle. Front Oncol 2019; 9:297. [PMID: 31069169 PMCID: PMC6491712 DOI: 10.3389/fonc.2019.00297] [Citation(s) in RCA: 170] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/01/2019] [Indexed: 12/14/2022] Open
Abstract
The human genetic code encrypted in thousands of genes holds the secret for synthesis of proteins that drive all biological processes necessary for normal life and death. Though the genetic ciphering remains unchanged through generations, some genes get disrupted, deleted and or mutated, manifesting diseases, and or disorders. Current treatment options—chemotherapy, protein therapy, radiotherapy, and surgery available for no more than 500 diseases—neither cure nor prevent genetic errors but often cause many side effects. However, gene therapy, colloquially called “living drug,” provides a one-time treatment option by rewriting or fixing errors in the natural genetic ciphering. Since gene therapy is predominantly a viral vector-based medicine, it has met with a fair bit of skepticism from both the science fraternity and patients. Now, thanks to advancements in gene editing and recombinant viral vector development, the interest of clinicians and pharmaceutical industries has been rekindled. With the advent of more than 12 different gene therapy drugs for curing cancer, blindness, immune, and neuronal disorders, this emerging experimental medicine has yet again come in the limelight. The present review article delves into the popular viral vectors used in gene therapy, advances, challenges, and perspectives.
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Affiliation(s)
- Reena Goswami
- Neuroscience Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen, MD, United States
| | - Gayatri Subramanian
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Liliya Silayeva
- Neuroscience Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen, MD, United States
| | - Isabelle Newkirk
- Neuroscience Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen, MD, United States
| | - Deborah Doctor
- Neuroscience Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen, MD, United States
| | - Karan Chawla
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Saurabh Chattopadhyay
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Dhyan Chandra
- Roswell Park Comprehensive Cancer Center, Buffalo, NY, United States
| | - Nageswararao Chilukuri
- Neuroscience Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen, MD, United States
| | - Venkaiah Betapudi
- Neuroscience Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen, MD, United States.,Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States
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9
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Wang Y, Hao L, Wang H, Santostefano K, Thapa A, Cleary J, Li H, Guo X, Terada N, Ashizawa T, Xia G. Therapeutic Genome Editing for Myotonic Dystrophy Type 1 Using CRISPR/Cas9. Mol Ther 2018; 26:2617-2630. [PMID: 30274788 PMCID: PMC6225032 DOI: 10.1016/j.ymthe.2018.09.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 08/30/2018] [Accepted: 09/06/2018] [Indexed: 12/18/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is caused by a CTG nucleotide repeat expansion within the 3' UTR of the Dystrophia Myotonica protein kinase gene. In this study, we explored therapeutic genome editing using CRISPR/Cas9 via targeted deletion of expanded CTG repeats and targeted insertion of polyadenylation signals in the 3' UTR upstream of the CTG repeats to eliminate toxic RNA CUG repeats. We found paired SpCas9 or SaCas9 guide RNA induced deletion of expanded CTG repeats. However, this approach incurred frequent inversion in both the mutant and normal alleles. In contrast, the insertion of polyadenylation signals in the 3' UTR upstream of the CTG repeats eliminated toxic RNA CUG repeats, which led to phenotype reversal in differentiated neural stem cells, forebrain neurons, cardiomyocytes, and skeletal muscle myofibers. We concluded that targeted insertion of polyadenylation signals in the 3' UTR is a viable approach to develop therapeutic genome editing for DM1.
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Affiliation(s)
- Yanlin Wang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Henan 450000, China
| | - Lei Hao
- Department of Neurology, The Fifth People's Hospital of Chongqing, Chongqing 400062, China
| | - Hongcai Wang
- Department of Neurology, Affiliated Hospital of Binzhou Medical University, Binzhou City, Shandong Province, China; Department of Neurology, University of New Mexico, Albuquerque, NM, USA
| | - Katherine Santostefano
- Department of Pathology, Immunology & Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Arjun Thapa
- Department of Neurology, University of New Mexico, Albuquerque, NM, USA
| | - John Cleary
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | - Hui Li
- Department of Neurology, University of Wisconsin, Madison, WI, USA
| | - Xiuming Guo
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Naohiro Terada
- Department of Pathology, Immunology & Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Tetsuo Ashizawa
- Houston Methodist Neurological Institute and Research Institute, 6670 Bertner Ave. R11-117, Houston, TX, USA
| | - Guangbin Xia
- Department of Neurology, University of New Mexico, Albuquerque, NM, USA; Department of Neuroscience, University of New Mexico, Albuquerque, NM, USA.
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10
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Waldman SA, Terzic A. Process Improvement for Maximized Therapeutic Innovation Outcome. Clin Pharmacol Ther 2018; 103:8-12. [PMID: 29265398 PMCID: PMC5745039 DOI: 10.1002/cpt.929] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 11/02/2017] [Indexed: 12/18/2022]
Abstract
Deconvoluting key biological mechanisms forms the framework for therapeutic discovery. Strategies that enable effective translation of those insights along the development and regulatory path ultimately drive validated clinical application in patients and populations. Accordingly, parity in What vs. How we transform novel mechanistic insights into therapeutic paradigms is essential in achieving success. Aligning molecular discovery with innovations in structures and processes along the discovery-development-regulation-utilization continuum maximizes the return on public and private investments for next-generation solutions in managing health and disease.
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Affiliation(s)
- Scott A Waldman
- Department of Pharmacology and Experimental Therapeutics, Division of Clinical Pharmacology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Andre Terzic
- Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota, USA
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11
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Site-specific chromosomal gene insertion: Flp recombinase versus Cas9 nuclease. Sci Rep 2017; 7:17771. [PMID: 29259215 PMCID: PMC5736728 DOI: 10.1038/s41598-017-17651-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 11/24/2017] [Indexed: 12/16/2022] Open
Abstract
Site-specific recombination systems like those based on the Flp recombinase proved themselves as efficient tools for cell line engineering. The recent emergence of designer nucleases, especially RNA guided endonucleases like Cas9, has considerably broadened the available toolbox for applications like targeted transgene insertions. Here we established a recombinase-mediated cassette exchange (RMCE) protocol for the fast and effective, drug-free isolation of recombinant cells. Distinct fluorescent protein patterns identified the recombination status of individual cells. In derivatives of a CHO master cell line the expression of the introduced transgene of interest could be dramatically increased almost 20-fold by subsequent deletion of the fluorescent protein gene that provided the initial isolation principle. The same master cell line was employed in a comparative analysis using CRISPR/Cas9 for transgene integration in identical loci. Even though the overall targeting efficacy was comparable, multi-loci targeting was considerably more effective for Cas9-mediated transgene insertion when compared to RMCE. While Cas9 is inherently more flexible, our results also alert to the risk of aberrant recombination events around the cut site. Together, this study points at the individual strengths in performance of both systems and provides guidance for their appropriate use.
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12
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Ma J, Pichavant C, du Bois H, Bhakta M, Calos MP. DNA-Mediated Gene Therapy in a Mouse Model of Limb Girdle Muscular Dystrophy 2B. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2017; 7:123-131. [PMID: 29159199 PMCID: PMC5684445 DOI: 10.1016/j.omtm.2017.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 10/19/2017] [Indexed: 11/26/2022]
Abstract
Mutations in the gene for dysferlin cause a degenerative disorder of skeletal muscle known as limb girdle muscular dystrophy 2B. To achieve gene delivery of plasmids encoding dysferlin to hind limb muscles of dysferlin knockout mice, we used a vascular injection method that perfused naked plasmid DNA into all major muscle groups of the hind limb. We monitored delivery by luciferase live imaging and western blot, confirming strong dysferlin expression that persisted over the 3-month time course of the experiment. Co-delivery of the follistatin gene, which may promote muscle growth, was monitored by ELISA. Immunohistochemistry documented the presence of dysferlin in muscle fibers in treated limbs, and PCR confirmed the presence of plasmid DNA. Because dysferlin is involved in repair of the sarcolemmal membrane, dysferlin loss leads to fragile sarcolemmal membranes that can be detected by permeability to Evan’s blue dye. We showed that after gene therapy with a plasmid encoding both dysferlin and follistatin, statistically significant reduction in Evan’s blue dye permeability was present in hamstring muscles. These results suggest that vascular delivery of plasmids carrying these therapeutic genes may lead to simple and effective approaches for improving the clinical condition of limb girdle muscular dystrophy 2B.
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Affiliation(s)
- Julia Ma
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA
| | - Christophe Pichavant
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA
| | - Haley du Bois
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA
| | - Mital Bhakta
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA
| | - Michele P Calos
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA
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13
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Guha TK, Wai A, Hausner G. Programmable Genome Editing Tools and their Regulation for Efficient Genome Engineering. Comput Struct Biotechnol J 2017; 15:146-160. [PMID: 28179977 PMCID: PMC5279741 DOI: 10.1016/j.csbj.2016.12.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/24/2016] [Accepted: 12/27/2016] [Indexed: 12/26/2022] Open
Abstract
Targeted genome editing has become a powerful genetic tool for studying gene function or for modifying genomes by correcting defective genes or introducing genes. A variety of reagents have been developed in recent years that can generate targeted double-stranded DNA cuts which can be repaired by the error-prone, non-homologous end joining repair system or via the homologous recombination-based double-strand break repair pathway provided a suitable template is available. These genome editing reagents require components for recognizing a specific DNA target site and for DNA-cleavage that generates the double-stranded break. In order to reduce potential toxic effects of genome editing reagents, it might be desirable to control the in vitro or in vivo activity of these reagents by incorporating regulatory switches that can reduce off-target activities and/or allow for these reagents to be turned on or off. This review will outline the various genome editing tools that are currently available and describe the strategies that have so far been employed for regulating these editing reagents. In addition, this review will examine potential regulatory switches/strategies that can be employed in the future in order to provide temporal control for these reagents.
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Affiliation(s)
| | | | - Georg Hausner
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T2N2, Canada
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14
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Waldman SA, Terzic A. Managing Innovation to Maximize Value Along the Discovery-Translation-Application Continuum. Clin Pharmacol Ther 2016; 101:8-12. [PMID: 27869291 DOI: 10.1002/cpt.551] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 10/31/2016] [Indexed: 01/22/2023]
Abstract
Success in pharmaceutical development led to a record 51 drugs approved in the past year, surpassing every previous year since 1950. Technology innovation enabled identification and exploitation of increasingly precise disease targets ensuring next generation diagnostic and therapeutic products for patient management. The expanding biopharmaceutical portfolio stands, however, in contradistinction to the unsustainable costs that reflect remarkable challenges of clinical development programs. This annual Therapeutic Innovations issue juxtaposes advances in translating molecular breakthroughs into transformative therapies with essential considerations for lowering attrition and improving the cost-effectiveness of the drug-development paradigm. Realizing the discovery-translation-application continuum mandates a congruent approval, adoption, and access triad.
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Affiliation(s)
- S A Waldman
- Department of Pharmacology and Experimental Therapeutics, Division of Clinical Pharmacology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - A Terzic
- Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota, USA
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