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CHO cells knocked out for TSC2 display an improved productivity of antibodies under fed batch conditions
Author(s) -
McVey Duncan,
Aronov Michael,
Rizzi Giovanni,
Cowan Alexis,
Scott Charo,
Megill John,
Russell Reb,
Tirosh Boaz
Publication year - 2016
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.25951
Subject(s) - mtorc1 , pi3k/akt/mtor pathway , autophagy , mtorc2 , microbiology and biotechnology , protein kinase b , biology , chinese hamster ovary cell , mechanistic target of rapamycin , cell culture , chemistry , biochemistry , phosphorylation , signal transduction , apoptosis , genetics
The kinase mTOR operates in two cellular complexes, mTORC1 and mTORC2. mTORC1 adjusts metabolic activity according to external growth conditions and nutrients availability. When conditions are prosperous, mTOR facilitates protein and lipid biosyntheses and inhibits autophagy, while under metabolic constraints, however, its attenuation induces a catabolic program, energy preservation and autophagy. CHO is a key cell line for manufacturing of biologics owing to its remarkable ability to grow to high densities and maintain protein production and secretion for extended times. While high mTOR activity has been associated with high productivity in CHO cells, its inhibition by rapamycin has also been documented to augment productivity via promotion of viability. Here using CRISPR/Cas9 editing we engineered CHO cells to enforce high mTORC1 activity by knocking‐out TSC2, a major mTOR inhibitory protein, or PTEN, a phosphatase that attenuates the PI3K/AKT/mTOR pathway. Only TSC2‐deleted cells exhibited a constitutive activation of mTORC1 under fed batch conditions. Cells grew larger in size, synthesized more proteins and displayed an over twofold elevation in their specific productivity. While peak viable cell density was compromised, overall titers increased to an extent dependent upon the parental clone. Our data underscore manipulation of TSC as a strategy to improve performance of CHO cell in bioreactors. Biotechnol. Bioeng. 2016;113: 1942–1952. © 2016 Wiley Periodicals, Inc.