Factors and Mechanisms Affecting the Secretion of Recombinant Protein in CHO Cells

The market demand for recombinant therapeutic proteins (RTPs) has promoted the development of various protein expression host and bioprocessing technologies. Since mammalian cells have the unique advantage of being able to direct the correct folding of proteins and provide post-translational processing such as complex glycosylation, the RTPs produced by them currently account for approximately 80% of the approved marketed RTPs. Among them, Chinese hamster ovary (CHO) cells are currently the preferred host cells for the production of RTPs. Production of RTPs in CHO cells involves the synthesis, processing, transport, and secretion of proteins. The secretion process of proteins is one of the key steps, which greatly limits the yield and quality of RTPs. Here, we review the recombinant protein secretion process of CHO cells and its influencing factors, and further discuss the optimization strategy for recombinant protein secretion and expression in CHO cells.