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Genetic Engineering & Biotechnology News | GENengnews.com | APRIL 15, 2017 | 19 CHO Power to the People All commercially available manufactur- ing-worthy CHO cell lines currently require some form of licensing. Terms vary, depend- ing on the provider and the degree to which the cells have been manipulated. Wild-type CHO lines adapted to suspen- sion growth in animal component-free me- dia are available for a relatively low initial fee, notes Jamie Freeman, Ph.D., product manager at Horizon Discovery, who adds that it is also his understanding that each time a product is filed under an IND, the provider receives an additional fee. Cells that have been manipulated to be null for the glu- tamine synthetase (GS) gene—which allows selection of high-expressing cells in media lacking glutamine (now pretty much indus- try-standard)—entail significant initial cost plus annual payments that rise with achiev- ing product milestones. "Therefore, almost all commercially avail- able cell lines incur significant downstream costs," explains Dr. Freeman. "Moreover, license agreements restrict users in modifica- tions they can make to the cells through gene editing or vector manipulation, and in media optimization as well." Horizon Discovery addressed these is- sues through the release of its GS-knockout CHO-K1 cell line for a one-time fee with no downstream costs, and by encouraging further innovation in CHO cell-line develop- ment. "We are doing this by releasing the se- quenced genome of our host cell line, which will be a significant resource," says Dr. Free- man. Horizon Discovery has also provided its cells gratis to aid in the advancement of basic research. "While we provide the cells with an ex- pression vector and a recommended cultur- ing protocol, we do not oblige their use," informs Dr. Freeman. "Customers are free to explore different options that fit their specific processes." Horizon Discovery generates CHO-K1 GS Null cells using its proprietary gene-ed- iting platform. The editing tool, rAAV, uses homologous recombination to create precise edits, from point mutations to whole exon knockouts. The company licenses rAAV as well as the rights to use it to engineer cells for bioproduction with no "reach through," which ensures use unfettered by intellectual property issues. Horizon Discovery uses the CRISPR/Cas9 gene-editing system to generate proof-of- concept edits in its cells. Once the company identifies targets with the greatest impact on desirable CHO cell-line improvements (for example, productivity or product quality), it uses rAAV to re-engineer the cells to provide a manufacturing-ready cell line. Horizon Discovery is also applying these technologies to modify a range of pathways in parallel, to continually improve the bio- manufacturing capabilities of its cells. "We're redefining the gold standard in cell-line tech- nology," Dr. Freeman tells GEN. "We ap- preciate the complexity of biological systems, and we understand the need to modulate several regulatory pathways in parallel to achieve the phenotype we are aiming for." Examples include cells that remain 100% viable at harvest, thus improving product quality (or the cells could be cultured longer, resulting in higher titres but at the expense of degradation of product generated earlier in the batch0. "If this modification is paired with an edit such as knocking out secreted proteases or sialidases," advises Dr. Free- man, "the resulting phenotype would be a synergy of the two, leading to increased titre with no compromise on quality." Horizon Discovery believes its minimal- ly IP-encumbered CHO cell lines will help lower manufacturing costs by increasing clone productivity, decreasing variability in product consistency, and improving biopro- duction efficiency. And as a business entity, Horizon Discovery recognizes the economic implications. "We are adopting a disruptive commer- cial approach to established technology," Dr. Freeman admits, "but future engineered lines will be truly disruptive technology. "We are attempting to improve the CHO cell factory beyond a pure selection system by rewiring the metabolism of the cell to maximize protein expression and secretion, achieve consistent product quality, and re- Connect Upstream for Increased Titers Achieve high titers by developing your own optimized medium and feed strategy in 5 months: Our CHOptimizer ® media optimization tool box combines the ambr ® 15 with an integrated DoE approach for efficient testing of different media mixtures and spent media analysis. A media expert will guide you through this process. www.connect-upstream.com Speed to Clinic Robust Production Quality by Design Increased Titers See Cell-Line Development on page 20 Bioprocessing