Dataset Information

Application of maltose as energy source in protein-free CHO-K1 culture to improve the production of recombinant monoclonal antibody.

ABSTRACT: Oligosaccharides are generally considered to be un-utilized for growth of mammalian cells because their permeability across the cell membrane is low. However, in our previous study, we discovered that CHO and HEK293 cells consume maltose in culture media without serum and glucose. This is interesting because the transporter for maltose in mammalian cells has not been discovered to-date, and the only animal disaccharide transporter that is recently discovered is a sucrose transporter. The application of oligosaccharides in mammalian cell-based biopharmaceutical manufacturing can be beneficial, because it can theoretically increase carbohydrate content of the culture medium and decrease lactate production. Here, we first determined that specific maltose consumption rate in CHO cells was similar to galactose and fructose at 0.257 ng/cell/day. We then demonstrated that CHO cells can be cultivated with reasonable cell growth using higher maltose concentrations. After which, we evaluated the use of maltose supplementation in the production of a recombinant monoclonal antibody in batch and fed-batch cultures, demonstrating improvements in recombinant monoclonal antibody titer of 15% and 23% respectively. Finally, glycosylation profiles of the antibodies were analyzed.

SUBMITTER: Leong DSZ

PROVIDER: S-EPMC5840386 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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Application of maltose as energy source in protein-free CHO-K1 culture to improve the production of recombinant monoclonal antibody.

Leong Dawn Sow Zong DSZ Teo Brian Kah Hui BKH Tan Janice Gek Ling JGL Kamari Hayati H Yang Yuan Sheng YS Zhang Peiqing P Ng Say Kong SK

Scientific reports 20180306 1

Oligosaccharides are generally considered to be un-utilized for growth of mammalian cells because their permeability across the cell membrane is low. However, in our previous study, we discovered that CHO and HEK293 cells consume maltose in culture media without serum and glucose. This is interesting because the transporter for maltose in mammalian cells has not been discovered to-date, and the only animal disaccharide transporter that is recently discovered is a sucrose transporter. The applica ...[more]

PMID: 29511312

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Project description:BackgroundTo ensure maximal productivity of recombinant proteins (rP) during production culture it is typical to encourage an initial phase of rapid cell proliferation to achieve high biomass followed by a stationary phase where cellular energies are directed towards production of rP. During many such biphasic cultures, the initial phase of rapid cell growth at 37 degrees C is followed by a growth arrest phase induced through reduction of the culture temperature. Low temperature induced growth arrest is associated with many positive phenotypes including increased productivity, sustained viability and an extended production phase, although the mechanisms regulating these phenotypes during mild hypothermia are poorly understood.ResultsIn this study differential protein expression in suspension CHO-K1 cells was investigated following a reduction of the culture temperature from 37 degrees C to 31 degrees C in comparison to standard batch culture maintained at 37 degrees C using 2D-DIGE (Fluorescence 2-D Difference Gel Electrophoresis) and mass spectrometry (MS). There is only limited proteomic analysis of suspension-grown CHO cells describing a direct comparison of temperature shifted versus non-temperature shifted cultures using 2D-DIGE. This investigation has enabled the identification of temperature-dependent as well as temperature-independent proteomic changes. 201 proteins were observed as differentially expressed following temperature shift, of which 118 were up regulated. Of the 53 proteins identified by MALDI-ToF MS, 23 were specifically differentially expressed upon reduction of the culture temperature and were found related to a variety of cellular functions such as regulation of growth (HNRPC), cap-independent translation (EIF4A), apoptosis (importin-alpha), the cytoskeleton (vimentin) and glycoprotein quality control (alpha glucosidase 2).ConclusionThese results indicate the extent of the temperature response in CHO-K1 cells and suggest a number of key regulatory proteins and pathways that are involved in modulating the response of cells to mild hypothermia. Regulation of these identified proteins and pathways could be useful for future approaches to engineer CHO cells for improved recombinant protein production.

Project description:Abstract We previously demonstrated that increased monoclonal antibody productivity in dihydrofolate reductase (DHFR)-amplified CHO cells correlates with phosphorylated transcription factor-cytomegalovirus (CMV) promoter interactions. In this article, we extend the characterization to include CMV promoter methylation and its influence on NFκB and CREB1 transcription factor binding to the CMV promoter in two families of DHFR-amplified CHO cell lines. CMV promoter methylation was determined using bisulfite sequencing. To overcome Sanger-sequencing limitations due to high CG bias and multiple transgenes copies, pyrosequencing was used to determine the frequency of methylated cytosines in regions proximal to and containing the NFκB and CREB1 transcription-factor consensus binding sites. Chromatin immunoprecipitation was performed to interrogate transcription factor–DNA interactions. Antibodies to CREB1 and NFκB were used to immunoprecipitate formaldehyde-crosslinked protein-DNA fractions, followed by reverse transcription quantitative real-time polymerase chain reaction to quantitate the number of copies of CMV-promoter DNA bound to the various transcription factors. The relative unmethylated fraction at the CREB1 and NFκB consensus binding sites determined by pyrosequencing was correlated with transcription factor binding as determined by chromatin immunoprecipitation. Azacytidine treatment reduced methylation in all treated samples, though not at all methylation sites, while increasing transcription. Distinct promoter methylation patterns arise upon clonal selection in different families of cell lines. In both cell line families, increased methylation was observed upon amplification. In one family, the NFκB binding-site methylation was accompanied by increased CREB1 interaction with the promoter. In the other cell line family, lower methylation frequency at the NFκB consensus binding site was accompanied by more NFκB recruitment to the promoter region. Statement of Significance: In this work, we have characterized the methylation pattern in various positions along the cytomegalovirus (CMV) promoter driving the expression of the mAb heavy chain and light chain in different clones. The interplay between the methylated regions of transcription-factor consensus binding sites and the nuclear proteins influences the transcript levels, leading to higher productivity phenotypes. Our workflow demonstrates a way to identify influencers of high transcriptional rates and identifies opportunities for transcription factor screening and rational synthetic promoter design, toward enhancing specific productivity in commercially applicable manufacturing processes.

Dataset Information

Application of maltose as energy source in protein-free CHO-K1 culture to improve the production of recombinant monoclonal antibody.

Publications

Application of maltose as energy source in protein-free CHO-K1 culture to improve the production of recombinant monoclonal antibody.

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