Biologics Technology Research Laboratories Biologics Division, Daiichi Sankyo Co., Ltd., 2716-1, Aza Kurakake, Oaza Akaiwa, Chiyoda-machi, Oura-gun, Gunma, 370-0503, Japan.
Faculty of Life Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto City, 603-8555, Japan.
Sci Rep. 2022 May 24;12(1):7239. doi: 10.1038/s41598-022-11342-1.
Chinese hamster ovary (CHO) cells are widely used for manufacturing antibody drugs. We attempted to clone a novel high-expression promoter for producing monoclonal antibodies (mAbs) based on transcriptome analysis to enhance the transcriptional abundance of mAb genes. The efficacy of conventional promoters such as CMV and hEF1α decrease in the latter phase of fed-batch cell culture. To overcome this, we screened genes whose expression was maintained or increased throughout the culture period. Since CHO cells have diverse genetic expression depending on the selected clone and culture medium, transcriptome analysis was performed on multiple clones and culture media anticipated to be used in mAb manufacturing. We thus acquired the Hspa5 promoter as a novel high-expression promoter, which uniquely enables mAb productivity per cell to improve late in the culture period. Productivity also improved for various IgG subclasses under Hspa5 promoter control, indicating this promoter's potential universal value for mAb production. Finally, it was suggested that mAb production with this promoter is correlated with the transcription levels of endoplasmic reticulum stress-related genes. Therefore, mAb production utilizing the Hspa5 promoter might be a new method for maintaining protein homeostasis and achieving stable expression of introduced mAb genes during fed-batch culture.
中国仓鼠卵巢（CHO）细胞被广泛用于生产抗体药物。我们试图通过转录组分析来克隆一种新的高表达启动子，用于生产单克隆抗体（mAb），以提高 mAb 基因的转录丰度。在补料分批细胞培养的后期，CMV 和 hEF1α 等传统启动子的功效降低。为了克服这一问题，我们筛选了在整个培养期间保持或增加表达的基因。由于 CHO 细胞的遗传表达因所选克隆和培养基的不同而不同，因此对预期用于 mAb 生产的多个克隆和培养基进行了转录组分析。因此，我们获得了 Hspa5 启动子作为一种新的高表达启动子，该启动子能够使细胞在培养后期独特地提高 mAb 生产力。在 Hspa5 启动子控制下，各种 IgG 亚类的生产力也得到了提高，表明该启动子具有 mAb 生产的普遍价值。最后，结果表明，该启动子与内质网应激相关基因的转录水平相关。因此，利用 Hspa5 启动子进行 mAb 生产可能是一种新的方法，用于在补料分批培养过程中维持蛋白质平衡并实现引入的 mAb 基因的稳定表达。
