(269e) Glyco-Engineering of CHO Cells for Improved Protein Quality

Glycosylation affects the quality of glycoproteins by influencing protein folding, stability, bioactivity, and therapeutic efficacy. Unfortunately, heterogeneous glycans and incomplete glycosylation are still the biggest issues in protein quality control. Owing to recent advances in gene editing technologies and the availability of CHO genome sequences, stable genetic engineering has become a remarkable approach to regulate glycosylation. In this study, CHO host cells were engineered using genome editing tools via modulating the enzymes involved in glycosylation pathway to produce proteins with enriched sialic acid and non-fucosylated glycan. Specifically, CHO DG44 host cell was first genetically engineered using overexpression and CRISPR/Cas9 simultaneously, followed by the human IgG1 producing cell line construction. The glycan structure of the production cell line was evaluated to confirm the increased sialic acid contents and absent core fucose structure. Finally, the engineered CHO DG44 cell was characterized using proteomics to develop an in-depth understanding of cell engineering on the expression of host cell proteins involved in glycosylation.