Effects of sericin on the production of albumin-EPO and cell viability in CHO cell cultures

초록

Chinese hamster ovary (CHO) cells are one of the predominant systems for the production of recombinant proteins among eukaryotic expression systems. Recently, various strategies have been studied on increasing specific productivity in CHO cell cultures. Sericin is a protein derived from silkworm hemolymph (SH). This antioxidant nutrient was used to enhance cell growth and production of recombinant proteins in mammalian cell cultures. The addition of sericin shows a positive effect on the growth of animal host cells. Moreover, many reports described the efficiency of sericin in stem cell growth and comparability to fetal bovine serum (FBS). In this study, we investigated the effects of sericin on the transfected CHO cells producing albumin-erythropoietin (Alb-EPO). It was found that the viable cell density and viability of CHO cells increased and the production of Alb-EPO was also significantly enhanced. Due to the function of sericin as a nutrient, cell death was reduced. Therefore, the production of Alb-EPO was improved with increased cell density. Addition of inhibitors against cell death such as dextran sulfate and N-acetylcystein in CHO cell cultures, higher cell viability was obtained with the combined use of sericin. Protein production phase in cell cycle (S1 phase) was prolonged with the presence of sericin. In addition, enhanced specific productivity (q) was also observed with sericin. In conclusion, it was apparent that the addition of adequate amount of sericin could increase the viability of CHO cells and accordingly enhance the production of recombinant Alb-EPO fusion protein.