Vanessa S Bandeira, Hélio A Tomás, Evren Alici, Manuel J T Carrondo, Ana S Coroadinha
{"title":"Disclosing the Parameters Leading to High Productivity of Retroviral Producer Cells Lines: Evaluating Random Versus Targeted Integration.","authors":"Vanessa S Bandeira, Hélio A Tomás, Evren Alici, Manuel J T Carrondo, Ana S Coroadinha","doi":"10.1089/hgtb.2016.149","DOIUrl":"https://doi.org/10.1089/hgtb.2016.149","url":null,"abstract":"<p><p>Gammaretrovirus and lentivirus are the preferred viral vectors to genetically modify T and natural killer cells to be used in immune cell therapies. The transduction efficiency of hematopoietic and T cells is more efficient using gibbon ape leukemia virus (GaLV) pseudotyping. In this context gammaretroviral vector producer cells offer competitive higher titers than transient lentiviral vectors productions. The main aim of this work was to identify the key parameters governing GaLV-pseudotyped gammaretroviral vector productivity in stable producer cells, using a retroviral vector expression cassette enabling positive (facilitating cell enrichment) and negative cell selection (allowing cell elimination). The retroviral vector contains a thymidine kinase suicide gene fused with a ouabain-resistant Na<sup>+</sup>,K<sup>+</sup>-ATPase gene, a potential safer and faster marker. The establishment of retroviral vector producer cells is traditionally performed by randomly integrating the retroviral vector expression cassette codifying the transgene. More recently, recombinase-mediated cassette exchange methodologies have been introduced to achieve targeted integration. Herein we compared random and targeted integration of the retroviral vector transgene construct. Two retroviral producer cell lines, 293 OuaS and 293 FlexOuaS, were generated by random and targeted integration, respectively, producing high titers (on the order of 10<sup>7</sup> infectious particles·ml<sup>-1</sup>). Results showed that the retroviral vector transgene cassette is the key retroviral vector component determining the viral titers notwithstanding, single-copy integration is sufficient to provide high titers. The expression levels of the three retroviral constructs (gag-pol, GaLV env, and retroviral vector transgene) were analyzed. Although gag-pol and GaLV env gene expression levels should surpass a minimal threshold, we found that relatively modest expression levels of these two expression cassettes are required. Their levels of expression should not be maximized. We concluded, to establish a high producer retroviral vector cell line only the expression level of the genomic retroviral RNA, that is, the retroviral vector transgene cassette, should be maximized, both through (1) the optimization of its design (i.e., genetic elements composition) and (2) the selection of high expressing chromosomal locus for its integration. The use of methodologies identifying and promoting integration into high-expression loci, as targeted integration or high-throughput screening are in this perspective highly valuable.</p>","PeriodicalId":13126,"journal":{"name":"Human Gene Therapy Methods","volume":"28 2","pages":"78-90"},"PeriodicalIF":0.0,"publicationDate":"2017-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/hgtb.2016.149","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34819075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bindu M. Nambiar, Cathleen Cornell Sookdeo, P. Berthelette, R. Jackson, S. Piraino, Brenda Burnham, Shelley Nass, D. Souza, C. O’Riordan, K. Vincent, Seng H. Cheng, D. Armentano, Sirkka Kyostio-Moore
{"title":"Characteristics of Minimally Oversized Adeno-Associated Virus Vectors Encoding Human Factor VIII Generated Using Producer Cell Lines and Triple Transfection.","authors":"Bindu M. Nambiar, Cathleen Cornell Sookdeo, P. Berthelette, R. Jackson, S. Piraino, Brenda Burnham, Shelley Nass, D. Souza, C. O’Riordan, K. Vincent, Seng H. Cheng, D. Armentano, Sirkka Kyostio-Moore","doi":"10.1089/hgtb.2016.124","DOIUrl":"https://doi.org/10.1089/hgtb.2016.124","url":null,"abstract":"Several ongoing clinical studies are evaluating recombinant adeno-associated virus (rAAV) vectors as gene delivery vehicles for a variety of diseases. However, the production of vectors with genomes >4.7 kb is challenging, with vector preparations frequently containing truncated genomes. To determine whether the generation of oversized rAAVs can be improved using a producer cell-line (PCL) process, HeLaS3-cell lines harboring either a 5.1 or 5.4 kb rAAV vector genome encoding codon-optimized cDNA for human B-domain deleted Factor VIII (FVIII) were isolated. High-producing \"masterwells\" (MWs), defined as producing >50,000 vg/cell, were identified for each oversized vector. These MWs provided stable vector production for >20 passages. The quality and potency of the AAVrh8R/FVIII-5.1 and AAVrh8R/FVIII-5.4 vectors generated by the PCL method were then compared to those prepared via transient transfection (TXN). Southern and dot blot analyses demonstrated that both production methods resulted in packaging of heterogeneously sized genomes. However, the PCL-derived rAAV vector preparations contained some genomes >4.7 kb, whereas the majority of genomes generated by the TXN method were ≤4.7 kb. The PCL process reduced packaging of non-vector DNA for both the AAVrh8R/FVIII-5.1 and the AAVrh8R/FVIII-5.4 kb vector preparations. Furthermore, more DNA-containing viral particles were obtained for the AAVrh8R/FVIII-5.1 vector. In a mouse model of hemophilia A, animals administered a PCL-derived rAAV vector exhibited twofold higher plasma FVIII activity and increased levels of vector genomes in the liver than mice treated with vector produced via TXN did. Hence, the quality of oversized vectors prepared using the PCL method is greater than that of vectors generated using the TXN process, and importantly this improvement translates to enhanced performance in vivo.","PeriodicalId":13126,"journal":{"name":"Human Gene Therapy Methods","volume":"28 1 1","pages":"23-38"},"PeriodicalIF":0.0,"publicationDate":"2017-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/hgtb.2016.124","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61229894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Min Chen, Kyungah Maeng, A. Nawab, R. Francois, J. Bray, M. Reinhard, S. Boye, W. Hauswirth, F. Kaye, Georgiy Aslanidi, A. Srivastava, M. Zajac-Kaye
{"title":"Efficient Gene Delivery and Expression in Pancreas and Pancreatic Tumors by Capsid-Optimized AAV8 Vectors.","authors":"Min Chen, Kyungah Maeng, A. Nawab, R. Francois, J. Bray, M. Reinhard, S. Boye, W. Hauswirth, F. Kaye, Georgiy Aslanidi, A. Srivastava, M. Zajac-Kaye","doi":"10.1089/hgtb.2016.089","DOIUrl":"https://doi.org/10.1089/hgtb.2016.089","url":null,"abstract":"Despite efforts to use adeno-associated viral (AAV) vector-mediated gene therapy for treatment of pancreatic ductal adenocarcinoma (PDAC), transduction efficiency remains a limiting factor and thus improvement of AAV delivery would significantly facilitate the treatment of this malignancy. Site-directed mutagenesis of specific tyrosine (Y) residues to phenylalanine (F) on the surface of various AAV serotype capsids has been reported as a method for enhancing gene transfer efficiencies. In the present studies, we determine whether Y-to-F mutations could also enhance AAV8 gene transfer in the pancreas to facilitate gene therapy for PDAC. Three different Y-to-F mutant vectors (a single-mutant, Y733F; a double-mutant, Y447F+Y733F; and a triple-mutant, Y275F+Y447F+Y733F) and wild-type AAV8 (WT-AAV8) were administered by intraperitoneal or tail-vein routes to KrasG12D+/-, KrasG12D+/-/Pten+/-, and wild-type mice. The transduction efficiency of these vectors expressing the mCherry reporter gene was evaluated 2 weeks post administration in pancreas or PDAC and correlated with viral genome copy numbers. Our comparative and quantitative analyses of the transduction profiles demonstrated that the Y-to-F double-mutant exhibited the highest mCherry expression in pancreatic tissues (range 45-70%) compared with WT-AAV8 (7%; p < 0.01). We also detected a 7-fold higher level of vector genome copy numbers in normal pancreas following transduction with the double-mutant AAV8 compared with WT-AAV8 (10,285 vs. 1,500 vector copies/μg DNA respectively, p < 0.05). In addition, we observed that intraperitoneal injection of the double-mutant AAV8 led to a 15-fold enhanced transduction efficiency as compared to WT-AAV8 in mouse PDAC, with a corresponding ∼14-fold increase in vector genome copy numbers (26,575 vs. 2,165 copies/μg DNA respectively, p < 0.05). These findings indicate that the Y447+Y733F-AAV8 leads to a significant enhancement of transduction efficiency in both normal and malignant pancreatic tissues, suggesting the potential use of this vector in targeting pancreatic diseases in general, and PDAC in particular.","PeriodicalId":13126,"journal":{"name":"Human Gene Therapy Methods","volume":"28 1 1","pages":"49-59"},"PeriodicalIF":0.0,"publicationDate":"2017-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/hgtb.2016.089","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47323417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Assaying the Stability and Inactivation of AAV Serotype 1 Vectors.","authors":"D. Howard, B. Harvey","doi":"10.1089/hgtb.2016.180","DOIUrl":"https://doi.org/10.1089/hgtb.2016.180","url":null,"abstract":"Adeno-associated virus (AAV) vectors are a commonplace tool for gene delivery ranging from cell culture to human gene therapy. One feature that makes AAV a desirable vector is its stability, in regard to both the duration of transgene expression and retention of infectivity as a viral particle. This study examined the stability of AAV serotype 1 (AAV1) vectors under different conditions. First, transducibility after storage at 4°C decreased 20% over 7 weeks. Over 10 freeze-thaw cycles, the resulting transduction efficiency became variable at 60-120% of a single thaw. Using small stainless steel slugs to mimic a biosafety cabinet or metal lab bench surface, it was found that an AAV1 vector can be reconstituted after 6 days of storage at room temperature. The stability of AAV is a desired feature, but effective decontamination procedures must be available for safety and experimental integrity. Multiple disinfectants commonly used in the laboratory for ability to inactivate an AAV1 vector were tested, and it was found that autoclaving, 0.25% peracetic acid, iodine, or 10% Clorox bleach completely prevented AAV-mediated transgene expression. These data suggest that peracetic acid should be used for inactivating AAV1 vectors on metal-based surfaces or instruments in order to avoid inadvertent transgene expression in human cells or cross-contamination of instruments.","PeriodicalId":13126,"journal":{"name":"Human Gene Therapy Methods","volume":"28 1 1","pages":"39-48"},"PeriodicalIF":0.0,"publicationDate":"2017-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/hgtb.2016.180","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43689334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Mietzsch, Henrik Hering, E. Hammer, M. Agbandje-McKenna, S. Zolotukhin, R. Heilbronn
{"title":"OneBac 2.0: Sf9 Cell Lines for Production of AAV1, AAV2, and AAV8 Vectors with Minimal Encapsidation of Foreign DNA.","authors":"M. Mietzsch, Henrik Hering, E. Hammer, M. Agbandje-McKenna, S. Zolotukhin, R. Heilbronn","doi":"10.1089/hgtb.2016.164","DOIUrl":"https://doi.org/10.1089/hgtb.2016.164","url":null,"abstract":"Recombinant adeno-associated viral (rAAV) vectors for human gene therapy require efficient and economical production methods to keep pace with the rapidly increasing clinical demand. In addition, the manufacturing process must ensure high vector quality and biological safety. The OneBac system offers easily scalable rAAV vector production in insect Sf9-derived AAV rep/cap-expressing producer cell lines infected with a single baculovirus that carries the rAAV backbone. For most AAV serotypes high burst sizes per cell were achieved, combined with high infectivity rates. OneBac 2.0 represents a 2-fold advancement: First, enhanced VP1 proportions in AAV5 capsids lead to vastly increased per-particle infectivity rates. Second, collateral packaging of foreign DNA is suppressed by removal of the Rep-binding element (RBE). In this study we show that this advancement of AAV5 packaging can be translated to OneBac 2.0-derived packaging systems for alternative AAV serotypes. By removal of the RBE, collateral packaging of nonvector DNA was drastically reduced in all newly tested serotypes (AAV1, AAV2, and AAV8). However, the splicing-based strategy to enhance VP1 expression in order to increase AAV5 infectivity hardly improved infectivity rates of AAV-1, -2, or -8 compared with the original OneBac cell lines. Our results emphasize that OneBac 2.0 represents an advancement for scalable, high-titer production of various AAV serotypes, leading to AAV particles with minimal packaging of foreign DNA.","PeriodicalId":13126,"journal":{"name":"Human Gene Therapy Methods","volume":"28 1 1","pages":"15-22"},"PeriodicalIF":0.0,"publicationDate":"2017-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/hgtb.2016.164","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42361488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A guide to approaching regulatory considerations for lentiviral-mediated gene therapies.","authors":"Michael White, R. Whittaker, Elizabeth A. Stoll","doi":"10.1089/hum.2017.096","DOIUrl":"https://doi.org/10.1089/hum.2017.096","url":null,"abstract":"Lentiviral vectors are increasingly the gene transfer tool of choice for gene or cell therapies, with multiple clinical investigations showing promise for this viral vector in terms of both safety and efficacy. The third-generation vector system is well-characterized, effectively delivers genetic material and maintains long-term stable expression in target cells, delivers larger amounts of genetic material than other methods, is non-pathogenic and does not cause an inflammatory response in the recipient. This report aims to help academic scientists and regulatory managers negotiate the governance framework to achieve successful translation of a lentiviral vector-based gene therapy. The focus is on European regulations, and how they are administered in the United Kingdom, although many of the principles will be similar for other regions including the United States. The report justifies the rationale for using third-generation lentiviral vectors to achieve gene delivery for in vivo and ex vivo applications; briefly summarises the extant regulatory guidance for gene therapies, categorised as advanced therapeutic medicinal products (ATMPs); provides guidance on specific regulatory issues regarding gene therapies; presents an overview of the key stakeholders to be approached when pursuing clinical trials authorization for an ATMP; and includes a brief catalogue of the documentation required to submit an application for regulatory approval of a new gene therapy.","PeriodicalId":13126,"journal":{"name":"Human Gene Therapy Methods","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/hum.2017.096","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61240522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Peter Bell, Lili Wang, Shu-Jen Chen, Hongwei Yu, Yanqing Zhu, Mohamad Nayal, Zhenning He, J. White, Deborah Lebel-Hagan, James M. Wilson
{"title":"Effects of Self-Complementarity, Codon Optimization, Transgene, and Dose on Liver Transduction with AAV8.","authors":"Peter Bell, Lili Wang, Shu-Jen Chen, Hongwei Yu, Yanqing Zhu, Mohamad Nayal, Zhenning He, J. White, Deborah Lebel-Hagan, James M. Wilson","doi":"10.1089/HGTB.2016.039","DOIUrl":"https://doi.org/10.1089/HGTB.2016.039","url":null,"abstract":"Numerous methods of vector design and delivery have been employed in an attempt to increase transgene expression following AAV-based gene therapy. Here, a gene transfer study was conducted in mice to compare the effects of vector self-complementarity (double- or single-stranded DNA), codon optimization of the transgene, and vector dose on transgene expression levels in the liver. Two different reporter genes were used: human ornithine transcarbamylase (hOTC) detected by immunofluorescence, and enhanced green fluorescent protein (EGFP) detected by direct fluorescence. The AAV8 capsid was chosen for all experiments due to its strong liver tropism. While EGFP is already a codon-optimized version of the original gene, both wild-type (WT) and codon-optimized (co) versions of the hOTC transgene were compared in this study. In addition, the study evaluated which of the two hOTC modifications-codon optimization or self-complementarity-would confer the highest increase in expression levels at a given dose. Interestingly, based on morphometric image analysis, it was observed that the difference in detectable expression levels between self-complementary (sc) and single-stranded (ss) hOTCco vectors was dose dependent, with a sevenfold increase in OTC-positive area using sc vectors at a dose of 3 × 109 genome copies (GC) per mouse, but no significant difference at a dose of 1 × 1010 GC/mouse. In contrast, with EGFP as a transgene, the increases in expression levels when using the sc vector were observed at both the 3 × 109 GC/mouse and 1 × 1010 GC/mouse doses. Furthermore, codon optimization of the hOTC transgene generated a more significant improvement in expression than the use of self-complementarity did. Overall, the results demonstrate that increases in expression levels gained by using sc vectors instead of ss vectors can vary between different transgenes, and that codon optimization of the transgene can have an even more powerful effect on the resulting expression levels.","PeriodicalId":13126,"journal":{"name":"Human Gene Therapy Methods","volume":"27 6 1","pages":"228-237"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/HGTB.2016.039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61229846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. SnookAdam, R. BaybuttTrevor, HyslopTerry, A. WaldmanScott
{"title":"Preclinical Evaluation of a Replication-Deficient Recombinant Adenovirus Serotype 5 Vaccine Expressing Guanylate Cyclase C and the PADRE T-helper Epitope.","authors":"E. SnookAdam, R. BaybuttTrevor, HyslopTerry, A. WaldmanScott","doi":"10.1089/HGTB.2016.114","DOIUrl":"https://doi.org/10.1089/HGTB.2016.114","url":null,"abstract":"There is an unmet need for improved therapeutics for colorectal cancer, the second leading cause of cancer mortality worldwide. Adjuvant chemotherapy only marginally improves survival in some patients and has no benefit in others, underscoring the clinical opportunity for novel immunotherapeutic approaches to improve survival in colorectal cancer. In that context, guanylate cyclase C (GUCY2C) is an established biomarker and therapeutic target for metastatic colorectal cancer with immunological characteristics that promote durable antitumor efficacy without autoimmunity. Preliminary studies established non-replicating human type 5 adenovirus (Ad5) expressing GUCY2C as safe and effective to induce GUCY2C-specific immune responses and antitumor immunity in mice. This study characterized the biodistribution, immunogenicity, and safety of a vector expressing GUCY2C fused with the human CD4+ T helper cell epitope PADRE (Ad5-GUCY2C-PADRE) to advance this vaccine into clinical trials in colorectal cancer patients...","PeriodicalId":13126,"journal":{"name":"Human Gene Therapy Methods","volume":"27 1","pages":"238-250"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1089/HGTB.2016.114","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61230107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}