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 transfection of the Epo gene was confirmed by an enzyme-linked immunoassay. Overexpression of EGFR was confirmed by Western blotting of EGFR. The transfected CHO cells were cultured in serum-free medium in the presence of soluble epidermal growth factor (EGF) or immobilized EGF. The CHO cells overexpressing EGFR grew in the presence of less EGF than the cells not overexpressing EGFR. In addition, the growth of EGFR-overexpressing CHO cells was enhanced in the presence of immobilized EGF more efficiently than in the presence of soluble EGF. The amount of Epo secreted from the cells increased linearly with the increase of growth rate. Consequently, culture of CHO cells coexpressing Epo and EGFR on EGF-immobilized matrix was the most efficient for Epo production.