title: Metabolic engineering of CHO cells to alter lactate metabolism during fed-batch cultures.
abstract: Recombinant yeast pyruvate carboxylase (PYC2) expression was previously shown to be an effective metabolic engineering strategy for reducing lactate formation in a number of relevant mammalian cell lines, but, in the case of CHO cells, did not consistently lead to significant improvement in terms of cell growth, product titer and energy metabolism efficiency. In the present study, we report on the establishment of a PYC2-expressing CHO cell line producing a monoclonal antibody and displaying a significantly altered lactate metabolism compared to its parental line. All clones exhibiting strong PYC2 expression were shown to experience a significant and systematic metabolic shift toward lactate consumption, as well as a prolonged exponential growth phase leading to an increased maximum cell concentration and volumetric product titer. Of salient interest, PYC2-expressing CHO cells were shown to maintain a highly efficient metabolism in fed-batch cultures, even when exposed to high glucose levels, thereby alleviating the need of controlling nutrient at low levels and the potential negative impact of such strategy on product glycosylation. In bioreactor operated in fed-batch mode, the higher maximum cell density achieved with the PYC2 clone led to a net gain (20%) in final volumetric productivity.
authors.affiliation: Département de Biochimie et médecine moléculaire, Université de Montréal, Montréal, Québec H3C 3J7, Canada; Life Sciences, NRC Human Health Therapeutics Portfolio, Building Montreal-Royalmount, National Research Council Canada, Montréal, Québec H4P 2R2, Canada. Electronic address: cecile.toussaint@umontreal.ca.
authors.forename: Cécile
authors.initials: C
authors.lastname: Toussaint
authors.affiliation: Département de Génie Chimique, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-ville, Montréal, Québec H3C 3A7, Canada. Electronic address: o.henry@polymtl.ca.
authors.forename: Olivier
authors.initials: O
authors.lastname: Henry
authors.affiliation: Département de Biochimie et médecine moléculaire, Université de Montréal, Montréal, Québec H3C 3J7, Canada; Life Sciences, NRC Human Health Therapeutics Portfolio, Building Montreal-Royalmount, National Research Council Canada, Montréal, Québec H4P 2R2, Canada. Electronic address: yves.durocher@nrc-cnrc.gc.ca.
authors.forename: Yves
authors.initials: Y
authors.lastname: Durocher
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis; D061249:Batch Cell Culture Techniques / Q000379:methods*; D019149:Bioreactors; D016466:CHO Cells / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D005947:Glucose / Q000378:metabolism; D006031:Glycosylation; D019344:Lactic Acid / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods*; D011766:Pyruvate Carboxylase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D011994:Recombinant Proteins; D019344:Lactic Acid; D011766:Pyruvate Carboxylase; D005947:Glucose
keywords: CHO cells; Fed-batch; Metabolic engineering; Monoclonal antibody; Pyruvate carboxylase