Optimizing recombinant protein production: comparative analysis of different CHO cell lines

Increasing the secretory capacity of various host systems for the production of high-quality recombinant proteins, particularly therapeutic proteins (biotherapeutics) and industrial enzymes is crucial for a sustainable bio-based economy. The high production costs of biotherapeutics limit patient access to novel therapies. Chinese Hamster Ovary (CHO) cells are the most commonly used production system, accounting for over 85% of current market products. Our research focuses on enhancing protein production in CHO cells by utilizing different cell lines and evaluating the burden on these cell lines by overexpressing a model protein.

The main objectives are to compare the protein production capacity of different CHO cell lines and to generate an optimized vector system for stable high-yield protein expression system. The cell lines studied include GIBCO-CHO-S, CHO-K1-SmaF, Freestyle CHO-S, and CHO-S. Protein estimation was performed for all cell lysates and secretome samples, followed by mass spectrometry (MS) analysis for protein identification and quantification. Transient expression studies with optimized plasmids were assessed using western blotting.

Initial protein estimation revealed substantial differences in total amounts of secreted proteins across cell lines. MS analysis identified 5700-5800 proteins in cell lysates, with secretome protein counts ranging from 1100 to 1600, of which only 20-25% were secreted proteins. The CHO-K1-SmaF cell line showed notable differences in protein secretion compared to others. Optimized plasmid constructs demonstrated higher protein expression in transient studies.

These findings suggest that selecting appropriate CHO cell lines and a better plasmid design are critical for enhancing protein production. This approach can improve industrial efficiency, reduce waste and lower costs benefiting numerous industrial applications. Ongoing experiments aim to develop more effective expression vectors and evaluate their performance in various CHO cell lines to further enhance production yields and streamline biotherapeutic manufacturing processes.