Supplementation of metal ions for shifting lactate metabolism in CHO cell cultures

초록

Chinese hamster ovary (CHO) cells are widely used in biopharmaceutical industries. In CHO cell cultures, lactate is produced and shows negative effects on cell growth such as the initiation of apoptosis. Lactate also affects the quality of recombinant protein. To reduce the negative effects of lactate, shifting of lactate metabolism has been considered. It has been known that high lactate production is correlated with mitochondrial oxidative metabolism. Copper (Cu), zinc (Zn), and magnesium (Mg) ions are the cofactors of cytochrome c oxidase which is the key enzyme in electron transport chain for the synthesis of ATP. In this study, Cu, Zn, and Mg were added for shifting lactate metabolism. Optimization of feeding strategy was performed by using simplex lattice design. Supplementation of 20.6 mg/L Cu and 9.3 mg/L Mg reduced lactate concentration to minimum level with the highest viable cell density and Alb-EPO titer. ATP concentration was increased up to 1.5-fold, and mitochondrial membrane potential was 20% higher than that of control. Furthermore, sialic acid content of Alb-EPO was increased by shifting lactate metabolism. In conclusion, it was found that the supplementation of metal ions could shift lactate metabolism, which resulted in the increase of the viability of CHO cells as well as the enhancement of the productivity of Alb-Epo.