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Enhanced sialylation of recombinant erythropoietin in genetically engineered Chinese‐hamster ovary cells
Author(s) -
Jeong Yeon Tae,
Choi One,
Son Young Dok,
Park Seung Yeol,
Kim Jung Hoe
Publication year - 2009
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1042/ba20080044
Subject(s) - chinese hamster ovary cell , recombinant dna , erythropoietin , ovary , biology , genetically engineered , microbiology and biotechnology , chemistry , cell culture , biochemistry , genetics , gene
Sialic acid, the terminal sugar in N ‐linked complex glycans, is usually found in glycoproteins and plays a major role in determining the circulatory lifespan of glycoproteins. In the present study we attempted to enhance the sialylation of recombinant EPO (erythropoietin) in CHO (Chinese‐hamster ovary) cells. To enhance EPO sialylation, we introduced human α2,3‐ST (α2,3‐sialyltransferase) and CMP‐SAS (CMP‐sialic acid synthase) into recombinant human EPO‐producing CHO cells. The sialylation of EPO was increased by the expression of α2,3‐ST alone. Although the co‐expression of α2,3‐ST and CMP‐SAS did not further increase sialylation, an increase in the intracellular pool of CMP‐sialic acid was noted. On the basis of these observations, it was postulated that the transport capacity of CMP‐sialic acid into the Golgi lumen was limited, thereby causing the reduced availability of CMP‐sialic acid substrate for sialylation. Therefore, we co‐expressed human α2,3‐ST and CMP‐SAS, as well as overexpress Chinese hamster CMP‐sialic acid transporter (CMP‐SAT) in CHO cells, which produced recombinant human EPO. When α2,3‐ST, CMP‐SAS, and CMP‐SAT were overexpressed in CHO cells, there was a corresponding increase in sialylation compared with the co‐expression of α2,3‐ST and CMP‐SAS. The present study provides a useful strategy for enhancing the sialylation of therapeutic glycoproteins produced in CHO cells.