Zinc supplementation increases protein titer of recombinant CHO cells
In order to study the impact of zinc and copper on the titer levels of mAb and recombinant protein in CHO cells, the IgG-expressing (DP12) and EPO-expressing (SK15) cell lines were cultured in chemically defined media with increasing concentrations of either metal. Supplementation with 25 mg/l in CDM media resulted in a significant increase in EPO (1.7-fold) and IgG (2.6-fold) titers compared to control (no added zinc). Titers at this Zn concentration in CDM containing the insulin replacing agent aurintricarboxylic acid (ATA) (CDM + A) showed a 1.8-fold (EPO) and 1.2-fold (IgG) titers increase compared to control. ATA appeared to also reduce the specific productivity (Qp) enhancement induced by Zn-25, with up to 4.9-fold (DP12) and 1.9-fold (SK15) Qp increase in CDM compared to the 1.6-fold (DP12) and 1.5-fold (SK15) Qp increase observed in CDM + A. A 31% reduced Viable Cell Density (VCD) in DP12 was observed in both Zn-supplemented media (3 × 106 cells/ml vs 4.2 × 106 cells/ml, day 5), whereas SK15 Zn-25 cultures displayed a 24% lower peak only in CDM + A (2.2 × 106 cells/ml vs 3.2 × 106 cells/ml, day 5). Supplementation with copper at 13.7–20 mg/l resulted in less significant cell line/product-type dependent effects on titer, VCD and Viability. Analysis of the energetic phenotype of both cell lines in 25 mg/l Zn-supplemented CDM media revealed a twofold increase in the oxygen consumption rate (OCR) compared to non-supplemented cells. Together, these data suggest that high zinc supplementation may induce an increase in oxidative respiration metabolism that results in increased Qp and titers in suspension CHO cultures.
KeywordsZinc Copper Titer Chinese Hamster Ovary cells (CHO) Erythropoietin (EPO) IgG
This work was conducted with the financial support of Scientific Foundation of Ireland (SFI) Grant No. [13/IA/1841] and Science Foundation Ireland co-funded by ERDF, Grant No. [12/RC/2275_P2].
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Conflict of interest
The authors declare that they have no conflict of interest.
- Gonzalez TN, Leong SR, Presta LG (2000) Humanized anti-IL-8 monoclonal antibodies. US6133426 http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=US-6133426-A
- Grillo CA, Reigosa MA, Lorenzo Fernández, de Mele MA (2010) Does over-exposure to copper ions released from metallic copper induce cytotoxic and genotoxic effects on mammalian cells? Contraception. https://doi.org/10.1016/J.CONTRACEPTION.2009.12.003 Google Scholar
- Gstraunthaler G (2003) Alternatives to the use of fetal bovine serum: serum-free cell culture. ALTEXGoogle Scholar
- Kelly PS, Dorival-García N, Paré S, Carillo S, Ta C, Alarcon Miguez A, Coleman O, Harper E, Shannon M, Henry M, Connolly L, Clynes M, Meleady P, Bones J, Barron N (2019) Improvements in single-use bioreactor film material composition leads to robust and reliable Chinese hamster ovary cell performance. Biotechnol Prog. https://doi.org/10.1002/btpr.2824 Google Scholar
- Qiping L, Hariprakash H, Kira GS, Christian S, Yang VL (2016) Intracellular zinc distribution in mitochondria, ER and the Golgi apparatus. Int J Physiol Pathophysiol Pharmacol. 8(1):35–43Google Scholar
- Zuqueli R, Prieto C, Etcheverrigaray M, Kratje R (2006) Effect of sodium butyrate and zinc sulphate supplementation on recombinant human IFN-β production by mammalian cell culture. Lat Am Appl Res (Vol. 36). http://www.scielo.org.ar/pdf/laar/v36n4/v36n4a18.pdf