The Effect Of Copper On CHO Cell Lactate Metabolism

With the increasing market demand for antibody drugs, it becomes more important in bio-pharmaceutical industry to know how to efficiently establish production processes with larger quantity and better quality. Therefore, this study focuses on optimization process of CHO cell culture by addressing the critical problem of lactic acid accumulation. Specifically, it studies the effects of the key component, the copper ions in culture medium, on the lactate metabolism shift.Firstly, two strains of CHO cells (cell line A and B) expressing two different monoclonal antibodies were investigated under the condition of copper ions addition. Cell line A produced lactate throughout the duration of the culture while cell line B consumed lactate and lactate concentration reduce 36.3% by adding copper ions during the later cultivation. Then, the author chose the cell line B whose lactic acid was consumed to be supplemented with different concentrations of copper. The results shown that the addition of copper ion in the range of 25～120 nmol/L led to the consumption of lactic acid in the late stage of the culture, and thus improved cell growth and titer were observed. Moreover, key enzymes activities of relevant metabolic pathways and intracellular redox state were found to play crucial roles under the condition of copper addition. Adding 120 nmol/L instead of 25 nmol/L of copper ions could result higher lactate consumption rate because it enhanced the activity of cytochrome C oxidase, promote cell energy metabolism, and improve the efficiency of malate-aspartate shuttle system, thus improve cell oxidation.This study provides important supports for the subsequent theoretical and practical strategies of fine-tuning CHO cell growth, metabolism and product expression by supplementation of copper. Besides, it also provides information to thoroughly understand the lactate metabolism shift in the process of CHO cell cultivation.