Key Challenges in Designing CHO Chassis Platforms

Abstract

Following the success of and the high demand for recombinant protein-based therapeutics during the last 25 years, the pharmaceutical industry has invested significantly in the development of novel treatments based on biologics. Mammalian cells are the major production systems for these complex biopharmaceuticals, with Chinese hamster ovary (CHO) cell lines as the most important players. Over the years, various engineering strategies and modeling approaches have been used to improve microbial production platforms, such as bacteria and yeasts, as well as to create pre-optimized chassis host strains. However, the complexity of mammalian cells curtailed the optimization of these host cells by metabolic engineering. Most of the improvements of titer and productivity were achieved by media optimization and large-scale screening of producer clones. The advances made in recent years now open the door to again consider the potential application of systems biology approaches and metabolic engineering also to CHO. The availability of a reference genome sequence, genome-scale metabolic models and the growing number of various “omics” datasets can help overcome the complexity of CHO cells and support design strategies to boost their production performance. Modular design approaches applied to engineer industrially relevant cell lines have evolved to reduce the time and effort needed for the generation of new producer cells and to allow the achievement of desired product titers and quality. Nevertheless, important steps to enable the design of a chassis platform similar to those in use in the microbial world are still missing. In this review, we highlight the importance of mammalian cellular platforms for the production of biopharmaceuticals and compare them to microbial platforms, with an emphasis on describing novel approaches and discussing still open questions that need to be resolved to reach the objective of designing enhanced modular chassis CHO cell lines.

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

“…The significant productivity enhancement was found in the cultures with the best cell growth, i.e., among those that contained hydrolysates (5% FHA, 1% FHN, and 1% FHP). Both apparent improvements in cell performance were not entirely proportional, but from the metabolic point of view, it is often assumed the cell growth boost comes at the expense of reduced cell-specific production [35]. Looking at the glucose (Figures 3C, 4C and 5C) and lactate (Figures 3D, 4D and 5D) concentration profiles, we cannot conclude that the beneficial effects of the hydrolysates were exclusively of nutritional character.…”

NAD+ supplementation improves mAb productivity in CHO cells via a glucose metabolic shift

“…Chinese hamster ovary (CHO) cells are considered a major mammalian host for the production of therapeutic proteins including monoclonal antibodies (mAbs) with several advantages for biomanufacturing; these include their ability to grow in chemically defined media in suspension cultures, human-compatible posttranslational modifications, and low susceptibility to viral infection. [1][2][3] However, the relatively low productivity of CHO cells compared to the prokaryotic expres-sion system remains a challenge to overcome. Two key parameters that determine culture phenotypes, such as productivity, cell growth, and specific productivity, are materials (i.e., building blocks such as amino acids and sugar) and energy represented by adenosine triphosphate (ATP).…”

Evaluation of site-specific methylation of the CMV promoter and its role in CHO cell productivity of a recombinant monoclonal antibody

“…[ 14 ]. In addition, this mechanistic understanding may influence design of synthetic promoters [ 15 ] and further the scope of next-generation cell line development [ 16 ].…”