Growth and secretion of erythropoietin of Chinese hamster ovary cells coexpressing epidermal growth factor receptor and erythropoietin genes: Design of cells for cell culture matrix

Chinese hamster ovary (CHO) cells were transfected with both genes encoding erythropoietin (Epo) and epidermal growth factor receptor (EGFR). The tran sfection of the Epo gene was confirmed by an enzyme-linked immunoassay. Ove rexpression of EGFR was confirmed by Western blotting of EGFR. The transfec ted CHO cells were cultured in serum-free medium in the presence of soluble epidermal growth factor (EGF) or immobilized EGF. The CHO cells overexpres sing EGFR grew in the presence of less EGF than the cells not overexpressin g EGFR. In addition, the growth of EGFR-overexpressing CHO cells was enhanc ed in the presence of immobilized EGF more efficiently than in the presence of soluble EGF. The amount of Epo secreted from the cells increased linear ly with the increase of growth rate. Consequently, culture of CHO cells coe xpressing Epo and EGFR on EGF-immobilized matrix was the most efficient for Epo production.