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Elucidating the Impact of CHO Cell Culture Media on Tryptophan Oxidation of a Monoclonal Antibody Through Gene Expression Analyses
Author(s) -
He Luhong,
Desai Jairav X.,
Gao Jinxin,
Hazeltine Laurie B.,
Lian Zhirui,
Calley John N.,
Frye Christopher C.
Publication year - 2018
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.201700254
Subject(s) - chinese hamster ovary cell , transcriptome , monoclonal antibody , gene expression , cell culture , gene , biology , microbiology and biotechnology , glutathione , oxidative phosphorylation , transgene , biochemistry , cell , chemistry , antibody , genetics , enzyme
Oxidation of monoclonal antibodies (mAb) is a common chemical modification with potential impact on a therapeutic protein's activity and immunogenicity. In a previous study, it was found that tryptophan oxidation (Trp‐ox) levels of two mAb produced in Chinese hamster ovary (CHO) cells were significantly lowered by modifying cell culture medium/feed. In this study, transcriptome analysis by RNA‐Seq is applied to further elucidate the underlying mechanism of those changes in lowering the Trp‐ox levels. Cell samples from the 5L fed‐batch conditions are harvested and subjected to RNA‐Seq analysis. The results showed that the cell culture changes had little impact on neither the expression of the mAb transgenes nor genes related to glycosylation. However, those changes did significantly alter the expression of multiple genes ( p‐ value ≤0.05 and absolute fold change ≥1.5 or adjusted p ‐value ≤0.1) involved in transport of copper, regulation of glutathione, iron storage, heme reduction, oxidative phosphorylation, and Nrf2‐mediated antioxidative response. These findings suggest a key underlying mechanism in lowering Trp‐ox levels by CDM was likely to be collectively controlling ROS levels through regulation of those genes’ expression. This is the first example, to our knowledge, applying transcriptomic analysis to mechanistically understand the impact of cell culture on mAb oxidation.