Enhanced Sialylation of Albumin-erythropoietin by Controlling Hexose Combination Ratios in CHO Cell Cultures

초록

Sialylation regulates the in vivo half-life of therapeutic proteins because sialic acids can prevent the glycoprotein from binding asialoglycoprotein receptors [1]. Glycan heterogeneity can be controlled by supplementing nucleotide-sugar precursors such as sugars [2]. In this study, we demonstrated the effects of hexose combination ratios (glucose:galactose:mannose) on sialyaltion of a fusion protein, albumin-erythropoietin (Alb-EPO), and cell perfomances. Since levels of nucleotide-sugars affect their interaction of each other, addition of carbon sources in combination can change the amount of sialylation on produced proteins, compared to those with separate addition. The hexoses were added in nine different conditions depending on the combination of three kinds of hexoses in two concentrations for each and one osmotic control. As a result of hexose feeding, there was more than 1.5-fold increase in sialylation of Alb-EPO followed by changed pool of nucleotide-sugars essential for sialylation process. At the same time, the titer of Alb-EPO was significantly increased by up to 1.7-fold in comparison to the control without deleterious effect on growth. In conclusion, our strategy of controlling the concentrations of available carbon sources offer a simple approach for the improved production of highly sialylated Alb-EPO.