Chinese hamster ovary (CHO) cells are currently the most widely used host cells for production of recombinant therapeutic proteins (RTPs). Small-molecule additives related to cell cycle apoptosis and autophagy regulation have been used to promote RTP production. By combining two small-molecule additives, positive synergistic effects on transgene expression were observed in CHO cells. In the present study, six small-molecule additives were used, including hydrocinnamic acid (HCA), sodium butyrate (NaB), lithium acetate (LiAc), sodium succinate dibasic hexahydrate (SDH), decitabine (DAC), and sodium propionate (SP). Experiments to test the effects of their pairwise combinations on two different recombinant CHO cell lines (rCHO) were designed using Design-Expert 12.0. Different effects of various pairs of small molecules on apoptosis- and autophagy-related protein expression were observed in the rCHOs. The results showed that compared to the control culture, NaB alone increased the volumetric yield and specific productivity (Qp) by 166% and 143%, respectively. The volumetric yield and Qp of NaB combined with DAC (Cg1)-treated cells increased by 178% and 212%, respectively. Cg1 selectively blocked the cells in the G0/G1 cell cycle stage. The relative expression levels of B-cell lymphoma 2 (Bcl-2), Beclin 1, and microtubule-associated protein light chain 3 (LC3B) in Cg1-treated CHO cells were significantly increased, while relative levels of cleaved caspase-3 expression were significantly decreased. In conclusion, Cg1 had the most obvious effect on RTP production and Qp in CHO cells, suggesting the Cg1 combination of small molecules may be used to improve the expression of recombinant protein in CHO cells.
Keywords: CHO cell; Cell apoptosis; Cell cycle; Recombinant protein drugs; Small molecule additives.
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