Optimization of Nucleotide sugar precursor feeding for enhancing sialylation in CHO cell cultures

초록

Chinese hamster ovary (CHO) cells have been widely used for the production of glycoproteins due to the?various?advantages?such?as?high productivity, ease of genetic manipulation, adaptability to serum-free media, and possibility of human-like glycosylation. Glycosylation of therapeutic proteins can affect biological activity, immunogenicity, targeting, and half-life. Especially, terminal sialic acid residues of N-glycans play an important role in determining the in vivo half-life. Highly sialylated glycans are essential to the activity of recombinant human erythropoietin (rhEPO), which can have a maximum of 14 sialic acids. Various strategies have been developed to enhance sialylation of rhEPO through nucleotide sugar precursor feeding. In this study, addition of nucleotide sugar precursors was optimized for increasing sialic acid content of albumin-erythropoietin (Alb-EPO). Glucosamine, galactose, and N-acetylmannosamine were added to CHO cell cultures during lag (day 0) or exponential phase (day 3). Central composite design and response surface methodology were used to evaluate the influence of nucleotide sugar precursors on the cell growth, titer, and sialic acid content. In exponential feeding strategy, culture performance was not altered by the addition of optimal precursor concentration, whereas sialic acid contents were increased 1.43-fold compared to those of control condition. Consequently, optimization of feeding strategy for supplementing nucleotide sugar precursors can provide efficient culture process for the production of highly sialylated glycans on Alb-EPO.