Recombinant Human Erythropoietin Production in Chinese Hamster Ovary Cells Is Enhanced by Supplementation of α-Helix Domain of 30Kc19 Protein

The enhancement of recombinant therapeutic protein production in mammalian cell culture has been regarded as an important issue in the biopharmaceutical industry. Previous studies have reported that the addition of the recombinant 30Kc19 protein, a silkworm-derived plasma protein with simultaneous cell-penetrating and mitochondrial enzyme-stabilizing properties, can enhance the recombinant protein expression in Chinese hamster ovary (CHO) cell culture. Here, we produced an α-helix N-terminal domain of 30Kc19, called (30Kc19α), and investigated its effects on the production of human erythropoietin (EPO), a widely used therapeutic protein for the treatment of anemia, in recombinant CHO cell culture. Similar to the full-length 30Kc19, 30Kc19α was able to be mass-produced in a form of recombinant protein through an Escherichia coli expression system and delivered into EPO-producing CHO (EPO–CHO) cells. Supplementing the medium of EPO–CHO cell culture with 30Kc19α increased the intracellular NADPH/NADP+ ratio related to the flux of metabolic reducing power for protein biosynthesis, subsequently enhancing EPO production in serum-free culture. 30Kc19α is considered to have certain advantages in the downstream purification process of therapeutic protein production when it is used as a medium supplement due to its small size and low isoelectric point compared to the full-length 30Kc19. These results suggest that 30Kc19α has potential use for manufacturing biopharmaceutical proteins.

Using MVDA with Stoichiometric Balances to Optimize Amino Acid Concentrations in Chemically Defined CHO Cell Culture Medium for Improved Culture Performance

Chemically defined (CD) media are routinely used in the production of biologics in Chinese Hamster Ovary (CHO) cell culture and provide enhanced raw material control. Nutrient optimized CD media is an important path to increase cell growth and monoclonal antibody (mAb) productivity in recombinant CHO cell lines. However, nutrient optimization efforts for CD media typically rely on multi-factorial and experimental design of experiment (DoE) approaches or complex mathematical models of cellular metabolism or gene expression systems. Moreover, the majority of these efforts are aimed at amino acids since they constitute essential nutrients in CD media as they directly contribute to biomass and protein production. In this study, we demonstrate the utilization of multi-variate data analytics (MVDA) coupled with amino acid stoichiometric balances (SBs) to increased cell growth and mAb productivity in efforts to reduce CD media development efforts. SBs measure the difference between theoretical demand of amino acids and the empirically measured fluxes to identify metabolic states of the cell. When coupled with MVDA, the statistical models were not only able to highlight key amino acids towards cell growth or productivity, but also provided direction on metabolic favorability of the amino acid. Experimental validation of our approach resulted in a 55% increase in total cell growth and about an 80% increase in total mAb productivity. Increased specific consumption of stoichiometrically balanced amino acids and decreased specific consumption of glucose was also observed in optimized CD media suggesting favorable consumption of desired nutrients and a potential for energy redistribution towards increased cellular growth or mAb productivity.

Protein Hydrolysates from Flaxseed Oil Cake as a Media Supplement in CHO Cell Culture

This is the first report about flaxseed protein hydrolysates applied as media supplements in CHO cell culture. The hydrolysates were produced by three separate enzymatic digestions of proteins isolated from flaxseed oil cake. The enzymes used were Alcalase, Neutrase, and Protamex, and the most efficient hydrolysis was achieved with Alcalase. The three hydrolysates were first tested as a partial substitute for serum in basal media in order to evaluate their effects on the adherent IgG-producing CHO cell line. The cells that grew in such media reached higher density than the cells in media supplemented with serum only. Consequently, the increased cell number improved the final IgG titer. In the next experiment, the impact of hydrolysates was evaluated in suspension CHO culture adapted to chemically defined media. In this preliminary investigation, the cells showed no response to the hydrolysate addition concerning the growth rate and productivity. Despite this outcome, we speculate that low molecular mass components in the hydrolysates, besides nutritive, may have a cell-protective function.