Overexpression of Tgm2 in Chinese Hamster Ovary Cells Enhances Recombinant Monoclonal Antibody Expression and Promotes Cell Proliferation through Reduction of Apoptosis

Chinese hamster ovary (CHO) cells are the preferred host system for producing protein-based (antibody) therapeutics. However, recombinant CHO cells undergo substantial apoptosis during prolonged cultivation, impairing cell growth and ultimately compromising product yield and quality. Transglutaminase 2 (Tgm2), which mediates post-translational modifications of substrate proteins, regulates critical biological processes including cellular differentiation, apoptosis, cell cycle progression, and extracellular matrix assembly. In this study, we examined the effects of Tgm2 overexpression and knockdown on CHO cell growth and recombinant antibody production. Stable Tgm2 overexpression enhanced CHO cell proliferation while reducing apoptotic rates, resulting in significantly increased recombinant adalimumab expression (2.09 ± 0.08-fold) and specific productivity (1.88 ± 0.08-fold) compared to controls. In contrast, Tgm2 knockdown promoted apoptosis and induced cell cycle arrest. Mechanistically, elevated Tgm2 upregulated antiapoptotic genes (Bcl-2, Bcl-xL, and Mcl-1) while suppressing caspase-3 activity and BAX expression. These effects were associated with PI3K/AKT/mTOR pathway activation. Our findings demonstrate that Tgm2 overexpression enhances proliferation, bolsters antiapoptotic capacity, and improves monoclonal antibody production efficiency in CHO cells, establishing it as a viable strategy for increasing recombinant protein yields.