Development of a non-protein and lipid medium adopted cell line for biopharmaceutical recombinant protein expression

Recently, many biopharmaceuticals have been developed such as cytokines, growth factors, and antibodies. These recombinant proteins are mostly expressed by CHO cells. However, the culture medium of CHO cells requires the addition of serum, which can contain unknown biological substances such as viruses, or requires the addition of expensive growth factors. To avoid the risks of biological ingredients and to decrease the cost of biopharmaceutical production, we developed a non-protein and lipid medium adopted (NPLAd) CHO cell line using the adapted culture method. Our results indicated that autocrine EGF production and insulin addition are essential for NPLAd CHO cell growth. However, the rate of cell proliferation of NPLAd CHO cells was decreased compared with original CHO-K1 cells. The proliferation of NPLAd CHO cells was improved by GM3 addition, suggesting increased signaling efficiency of autocrine factors. No difference was found in the growth rate between original CHO-K1 and NPLAd CHO cells supplemented with insulin and GM3. The productivity of recombinant protein in NPLAd CHO cells was verified using secreting luciferase reporter system. As a result, luciferase activity in NPLAd CHO cells showed more than three times higher than in the original CHOK1 cells. The results suggested that this cell line could be useful for biopharmaceutical recombinant protein.