An approach to further enhance the cellular productivity of exogenous protein hyper-producing Chinese hamster ovary (CHO) cells

Kiichiro Teruya, Yoshihito Daimon, Xiao Yan Dong, Yoshinori Katakura, Takumi Miura, Akira Ichikawa, Tsukasa Fujiki, Makiko Yamashita, Tetsuya Mori, Hideya Ohashi, Sanetaka Shirahata

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


The cell line D29, which was easily and rapidly established by the promoter-activated production and glutamine synthetase hybrid system, secreted recombinant human interleukin-6 (hIL-6) at a productivity rate of 39.5 μg 10-6 cells day-1, one of the highest reported levels worldwide. The productivity rate was about 130-fold higher than that of the cell line A7, which was established without both promoter activation and gene amplification. Although D29 cells had a high copy number and high mRNA level of the hIL-6 gene as well as a high secretion rate of hIL-6, large amounts of intracellular hIL-6 protein accumulated in D29 cells compared to A7 cells. Northern blotting analysis showed no change in the GRP78/BiP expression level in D29 cells. In contrast, an electrophoresis mobility shift assay revealed strong activation of NF-κB in D29 cells. These results suggest that large amounts of hIL-6 translated from large amounts of hIL-6 mRNA cause excess accumulation of intact hIL-6 in the endoplasmic reticulum (ER), and that subsequent negative feedback signals via the ER overload response inhibit hIL-6 protein secretion. To enhance the hIL-6 productivity rate of D29 cells by releasing the negative feedback signals, the effect of pyrrolidinedithiocarbamate, an inhibitor of NF-κB activation, was examined. Suppression of NF-κB activation in D29 cells produced a 25% augmentation of the hIL-6 productivity rate. Therefore, in highly productive cells like D29 cells, the release of negative feedback signals could increase the total amount of recombinant protein secretion.

Original languageEnglish
Pages (from-to)29-36
Number of pages8
Issue number1-3
Publication statusPublished - Jan 2005

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Bioengineering
  • Biomedical Engineering
  • Clinical Biochemistry
  • Cell Biology


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