Enhancing hCTLA4-Ig productivity by controlling the feeding time of 4-phenylbutyrate in CHO cell cultures

초록

CHO cell line is the most used mammalian cells for the production of therapeutic proteins. Cell cycle inhibitors have been applied for enhancing the protein productivity [1]. Especially, 4-phenylbutyrate (4-PBA), as a cell cycle arrest inducer, can improve the productivity in cell cultures and also has an adverse effect on cell growth. It shows cytotoxicity when it is present in culture medium [2]. In this study, we controlled the feeding time of 4- PBA for minimizing cytotoxicity in order to prolong culture period and enhance the production of hCTLA4-Ig. Various concentrations (0.1, 0.5, 1, 2 mM) of 4-PBA were added with initial feeding, exponential-phase feeding,interval feeding, and daily feeding. Cell viability was reduced in the presence of 4-PBA compared with the control condition, whereas productivity of hCTLA4-Ig was increased at all conditions along with prolonged culture period. as a result of cell cycle analysis, G1 arrest, which is related to protein productivity, was occurred the highest level in 4-PBA feeding condition. Furthermore, each feeding time shows different cell cycle arrest pattern, so the proportion of cell cycle can be controlled by regulating 4-PBA feeding time. It was demonstrated that control of feeding time of cell cycle inhibitors can improve the productivity of hCTLA4-Ig. In conclusion,regulation of feeding time of 4-PBA can maximize the productivity more effectively.