Cell culture and gene transcription effects of copper sulfate on Chinese hamster ovary cells

Abstract

This study reports the effects of varying concentrations of copper sulfate on the metabolic and gene transcriptional profile of a recombinant Chinese hamster ovary (CHO) cell line producing an immunoglobulin G (IgG)-fusion protein (B0). Addition of 50 μM copper sulfate significantly decreased lactate accumulation in the cultures while increasing viable cell density and protein titer. These changes could be seen from day 6 and became increasingly evident with culture duration. Reducing the copper sulfate concentration to 5 μM retained all the above beneficial effects, but with the added benefit of reduced levels of the aggregated form of the B0 protein. To profile the cellular changes due to copper sulfate addition at the transcriptional level, Affymetrix® CHO microarrays were used to identify differentially expressed genes related to reduced cellular stresses and facilitated cell cycling. Based on the microarray results, down-regulation of the transferrin receptor and lactate dehydrogenase, and up-regulation of a cytochrome P450 family-2 polypeptide were then confirmed by Western blotting. These results showed that copper played a critical role in cell metabolism and productivity on recombinant CHO cells and highlighted the usefulness of microarray data for better understanding biological responses on medium modification.

Improving lactate metabolism in an intensified CHO culture process: productivity and product quality considerations

“…One particular trace element, copper, has been identified to be necessary in promoting cell growth and inducing lactate consumption in a wide range of CHO cell lines [20][21][22][23]. Cultures with copper deficiency have been found to lose the ability in consuming lactate in the stationary phase.…”

Nutrient and metabolite analysis: understanding cell culture

“…The concentration of copper has been linked to the presence of free thiol and proline amidation [12,13], as well as to the control of lactate metabolism [14]. Iron source and concentration have been shown to impact the color of the final drug substance as well as the charge variant profile [9].…”

5.1 Physiology and Metabolism of Animal Cells for Production

“…The presence of copper in the medium also plays a significant role in the transcriptional regulation of lactate production in CHO cells [62,63]. An optimum concentration of 5 µmol L -1 Cu 2+ in the medium resulted in significant reduction of lactate production by down-regulating lactate dehydrogenase enzyme and improved cell density and product titer [63].…”