(365b) Comparative Proteomic Analysis of Host and High Biopharmaceuticals Producing CHO Cell Lines

One important target in biopharmaceutical industry is to achieve a high production of therapeutic protein. However, the effect of different host cells on protein expression has not been fully understood, so it is very challengeable to rationally design host cells and construct production cell lines. In this study, comparative proteomics was performed to investigate the host cell proteins that could correlate with the expression of recombinant therapeutic proteins. The global protein maps and biopharmaceutical production of four cell lines were analyzed and compared, including adapted ATCC CHO/dhfr-­, CHO/dhfr-­/EPO, Life Tech CHO DG44, and CHO DG44/IgG. All the host cells and production cell lines were cultivated in suspension culture using chemical defined medium. The productivity analysis in a simple fed-bath cell culture with glucose feeding was performed in shaker flask, showing that the ATCC CHO/dhfr-/EPO produced erythropoietin with titer of 421 mg/L and the CHO DG44/IgG produced IgG with titer of 1,385 mg/L. The LC/MS/MS was used to create the profiles of the global intracellular proteins of these four cell lines, and more than 1,000 host proteins were analyzed. The host proteins associated with metabolism of carbon and energy in glycolysis pathway, TCA cycle and amino acids were investigated. Other proteins involved in, such as protein processing (e.g. protein disulfide-isomerase A3 and endoplasmin), cytoskeletal structure (e.g. alpha-actinin-4 and vimentin) and cell cycle control (e.g. heat shock protein HSP 90-alpha and cyclin-dependent kinase 1), were also analyzed. The possible host cell regulators that correlate with different dhfr- host cells and different therapeutic proteins were identified although further investigation is needed. This study provided a deep insight into the regulation mechanism of biopharmaceutical productions by CHO cells. The results could be used to direct the rational cell engineering for new-generation host cells in the future.