title: Understanding translational control mechanisms of the mTOR pathway in CHO cells by polysome profiling.
abstract: The mammalian target of rapamycin (mTOR) pathway plays essential roles in the regulation of translational activity in many eukaryotes. Thus, from a bioprocessing point of view, understanding its molecular mechanisms may provide potential avenues for improving cell culture performance. Toward this end, the mTOR pathway of CHO cells in batch cultures was subjected to rapamycin treatment (inhibition) or nutrient supplementation (induction) and translational activities of CHO cells producing a monoclonal antibody (mAb) were evaluated with polysome profiling technology. Expectedly, rapamycin induced a shift of mRNAs from polysomes towards monosomes, thus reducing maximum cellular growth rate by 30%, while feeding additional nutrients extended mTOR pathway activity during the stationary growth phase in control batch culture, thereby contributing to an increase in global translation activity by up to 2-fold, and up to 5-fold higher specific translation of the heavy and light chains of the recombinant mAb. These increases in translation activity correlated with a 5-day extension in cellular growth and a 4-fold higher final product titer observed upon nutrient feeding. This first study of the relationship between the mTOR pathway and translational activity in CHO cultures provides key insights into the role of translational control in supporting greater productivity, which will lead to further enhancement of CHO cultures.
authors.affiliation: Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576, Singapore.
authors.forename: Franck C
authors.initials: FC
authors.lastname: Courtes
authors.affiliation: Institute of Medical Biology, Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, Singapore 138648, Singapore.
authors.forename: Leah
authors.initials: L
authors.lastname: Vardy
authors.affiliation: AbbVie Pte Ltd, 8 Biomedical Grove, #03-01 Neuros, Singapore 138665, Singapore.
authors.forename: Niki S C
authors.initials: NS
authors.lastname: Wong
authors.affiliation: Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore.
authors.forename: Muriel
authors.initials: M
authors.lastname: Bardor
authors.affiliation: Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576, Singapore.
authors.forename: Miranda G S
authors.initials: MG
authors.lastname: Yap
authors.affiliation: Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576, Singapore. Electronic address: cheld@nus.edu.sg.
authors.forename: Dong-Yup
authors.initials: DY
authors.lastname: Lee
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D011132:Polyribosomes; D014176:Protein Biosynthesis / Q000187:drug effects*; D011994:Recombinant Proteins / Q000096:biosynthesis; D020123:Sirolimus / Q000494:pharmacology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D007166:Immunosuppressive Agents; D011994:Recombinant Proteins; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus