Biomedical Engineering and Bioengineering Commons^™

Adaptation Of Cho Metabolism To Long Term Phosphate Limitation, Mugdha Gadgil

Cell Culture Engineering XV

Phosphate is an important component of abundant intracellular molecules like RNA, is a critical component of energy metabolism and is involved in substrate phosphorylation in cellular metabolism and signaling. Inorganic phosphate (P_i) is transported through specialized transporter proteins and limitation in the availability of phosphate in the growth medium limits cell growth. P_i concentrations have been reported to regulate the rates of aerobic glycolysis and oxygen uptake. Thus it is expected that cellular metabolism will adapt to long term phosphate restriction. Since complete phosphate deprivation will result in lack of growth, such an adaptation needs to be …

Using Definitive Screening Design To Effectively Assess The Combinatorial Impacts Of Media Supplements On Monoclonal Antibody Production In Mammalian Cells, Aaron Chen

Cell Culture Engineering XV

Process understanding is an essential component of QbD principles. Cell culture media composition can impact many process performance parameters such as viable cell density, product yield and product quality attributes. In order to enhance process understanding and exert better process control, numerous media supplements have previously been tested. However, their combinatorial effects on process and product quality have largely been unexplored. This is partially due to the resource and efforts required to execute relatively large size of experiment and data analysis.

Recent advancement in modern design of experiment methodology has alleviated this issue. The definitive screening design (DSD) allows for …

The Oxygen Binding Protein, Hemoxcell(R), Increases Cho Cell Growth And Extends Viability By Enhancing Oxygen Delivery, Katrin Braasch

Cell Culture Engineering XV

The continuous monitoring of cell growth and viability is an integral part of biopharmaceutical production. Measurements of changes in the polarizability of individual cells can identify early emerging sub-populations of apoptotic cells in a dielectrophoretic (DEP) cytometer designed at the University of Manitoba. In this instrument the trajectory of individual cells was tracked as they passed through a bank of electrodes (sensitivity: 0.1 µm; rate: 5 cells per second) designed to differentially perturb the cells according to their polarizability. This perturbation was recorded as a force index (FI), which was related to the electrical displacement of the cells. Using this …

Antibody Production With Site-Specific Non-Natural Amino Acid Incorporation For Generation Of Antibody Drug Conjugates, Alyssa Powell

Cell Culture Engineering XV

Ambrx’s mammalian expression platform (EuCODE) enables site-specific incorporation of non-natural amino acids into antibodies. This EuCODE technology provides a means for stable payload linkages at defined sites and with a defined DAR of 2 for antibody drug conjugate (ADC) generation. While the ability to control the DAR and payload site can provide an advantage to an ADC, the incorporation of the non-natural amino acid into the antibody heavy chain introduces a unique challenge for antibody production.

To achieve high production of monoclonal antibodies (mAbs) containing non-natural amino acids, we engineered a CHO-K1 cell line which stably contains Ambrx’s patented tRNA …

The Differential Polarizability Of Cho Cells Can Be Used To Monitor Changes In Metabolism, Katrin Braasch

Cell Culture Engineering XV

The continuous monitoring of cell growth and viability is an integral part of biopharmaceutical production. Measurements of changes in the polarizability of individual cells can identify early emerging sub-populations of apoptotic cells in a dielectrophoretic (DEP) cytometer designed at the University of Manitoba. In this instrument the trajectory of individual cells was tracked as they passed through a bank of electrodes (sensitivity: 0.1 µm; rate: 5 cells per second) designed to differentially perturb the cells according to their polarizability. This perturbation was recorded as a force index (FI), which was related to the electrical displacement of the cells. Using this …

A Community Genome-Scale Model Of Chinese Hamster Ovary Cell Metabolism Identifies Differences In The Efficiency Of Resource Utilization For Various Bioprocesses, Hooman Hefzi

Cell Culture Engineering XV

Genome-scale models of metabolism have successfully been employed in many microbial and eukaryotic metabolic engineering efforts by guiding pathway engineering and media optimization. They have also been used to explore the genotype-phenotype relationship in mammalian cells. The publication of the genomic sequence for Chinese hamster ovary (CHO) cells has allowed generation of genome-scale metabolic models (GeMs) for this organism. Here we have developed a high-quality community CHO GeM via careful reconciliation and manual curation of three independently developed CHO GeMs. This metabolic model, consisting of over 4000 metabolites and 6000 reactions, is capable of integrating proteomic, transcriptomic, and metabolomic data …

A Bioinformatic Pipeline For Studying Ribosome Occupancy In Cho Cells, Shangzhong Li

Cell Culture Engineering XV

No abstract provided.

Implementation And Evaluation Of A High-Throughput Sirna Screening System For Suspension Cho Cells, Gerald Klanert, Daniel Fernandez, Vaibhav Jadhav, Nicole Borth

Cell Culture Engineering XV

Chinese Hamster Ovary (CHO) cells are the most frequently used mammalian cell factory for the production of human-like recombinant proteins. Due to existing limitations in growth and protein production, genetic optimization of CHO cell lines may significantly enhance bioprocess productivities. Knockdown of genes by siRNAs is a standard method to identify genes involved in a desirable phenotype, either because their knockdown improves or degenerates the property. As at least 13000 different transcripts are present in a cell at any time, it is of interest to develop a method that is able to efficiently test the effect of gene knockdown at …

Elucidating Cell Line And Tissue Differences Derived From Cricetulus Griseus By Transcriptomics And Proteomics, Kelley Heffner

Cell Culture Engineering XV

Chinese hamster ovary (CHO) cells derived from Cricetulus griseus remain the dominant host for recombinant protein production. This project aims to expand our knowledge by conducting transcriptomics and proteomics experiments on CHO cell lines and Chinese hamster tissues in order to obtain a larger set of genetic engineering targets for improving bioprocess development. This study will increase data sets using cell line comparisons and investigate how mRNA and protein levels change from Chinese hamster lineage. Quantitative ‘omics data from CHO cell lines and Chinese hamster tissues data was obtained by RNAseq (transcriptome) and labeled tandem mass tag mass spectrometry (proteome). …

High Titer Transient Gene Expression Platform Based On Gs Cho Cell Line – Rapid Protein Expression Tool For Preclinical Drug Development, Yasha Rajendra, Gavin Barnard

Cell Culture Engineering XV

Most of the high yielding transient gene expression (TGE) methods for CHO cells reported in the literature involve extensive cell line engineering and plasmid vector optimization in addition to long fed batch cultures lasting up to 21 days. However, this is a laborious, time intensive process and also requires specific vector engineering for transient expression. Here, we present results from development of a high titer TGE process based on GS-CHO cells without resorting to host cell line engineering or TGE specific vector engineering. This was achieved by optimization of direct addition of DNA and PEI, use of DMA to enhance …

Technical Evaluation Of Rna-Seq And Microarray Approaches In Comparative Transcriptomics Analysis Of Cho Cells, Chun Chen, Huong Le, Chetan Goudar

Cell Culture Engineering XV

RNA-Seq has been replacing microarrays as the primary tool for comparative transcriptomics analysis. However, successful application of RNA-Seq to profile Chinese hamster ovary cells (CHO), the leading industrial cell line for recombinant protein production, was limited, primarily because of the inadequacy of genomic information for CHO cells. A compromised alternative to perform gene expression analysis and pathway or GO enrichment analysis in CHO cells was to map CHO genes to their mouse orthologs. Recent increased availability of CHO genomic references and the KEGG pathway reference for Chinese hamster has enabled direct gene expression analysis in the genome context of CHO …

A Rapid Approach For Basal And Feed Media Optimization In Ambr® 15 Bioreactors, Michael Gillmeister

Cell Culture Engineering XV

A Chemically-Defined (CD) and Animal Origin-Free (AOF) custom media optimization approach was developed using the ambr^® 15 microbioreactor system. This approach combines pre-qualified blends of well-characterized media, a series of high-throughput Design of Experiment (DoE) studies and analyses to optimize a fed-batch process, and on-site dedicated media application specialist support. This system can be utilized when commercially available media fall short of performance expectations and high-producing cell lines must be developed as quickly as possible. In comparison, fully customized media and feed development requires significant funding, time, and in-house expertise in media development. Using this media optimization approach, a …

Overcoming Scale-Up Challenges With A Non-Robust Cell Line, Sigma Mostafa, Brian Baker, Abhinav Shukla

Cell Culture Engineering XV

Cell culture scale up success depends on robust cell line, process, and equipment. Mixing characteristics of bench scale through large scale bioreactors need to be well understood and a reliable scale up parameter needs to be used. The cell culture raw material lot to lot variability as well as hydration protocol reliability needs to be considered. The cell culture process parameter ranges need to be broad enough to account for system variability and the process should not run at the edge of failure. In our experience, greater than 95% of cell lines are robust and easily scalable. Cell line robustness …

Optimization Of Glycosylation And Charge Distribution Through Culture Parameters And Supplements, Sigma Mostafa, Ventaka Tayi, Shahid Rameez, Nathan Oien, Jaspreet Notey, Brian Baker, Jimmy Smedley, Abhinav Shukla

Cell Culture Engineering XV

Culture parameters are known to have significant impacts on product quality, although these effects are sometimes cell-line dependent and the directionality of the effect has to be determined empirically. We will present data from three case studies where glycosylation or charge distribution was modified to match the reference molecule or to reduce variability. In the first case study, glycan optimization for a biosimilar will be described. Galactose, fucose, and mannose levels were optimized through screening of raw materials and process parameters. A range of media, feed, alternate sugars, metals and other supplements as well as temperature set points were tested. …

Lensless Imaging For Continuous Cho Viable Cell Density Monitoring In Bioreactors, Geoffrey Esteban, Martin Pisaneschi, Jeremie Cubeta, David Sergeant

Cell Culture Engineering XV

During suspension cell cultures in bioreactors, traditional measure for cell count and cell viability still rely on sampling and staining protocol where the Trypan Blue exclusion method is performed once a day. While automatic cell counters have reduced the statistical error of the original manual method, sampling the bioreactor is a risk for contamination and is prohibiting the use of such method for process control as the sampled volume becomes significant. Lensless Imaging Technology is a new breakthrough method for accurately and precisely determine cell concentration and viability without staining. This technique has the unique capability of acquiring microscopy images …

Crispr-Cas9 Knockout Library For Cho, Lasse Ebdrup, Alex Thomas, Hooman Hefzi, Philipp Spahn, Kaen Karottki, Helene Kildegaard, Nathan Lewis

Cell Culture Engineering XV

Traditionally, screening of large CHO cell population have been utilized to identify clones with desired phenotypic properties such as product quality, e.g. specific glyco forms, and population characteristics, e.g. ability to grow in high cell densities.

This has largely depended on the genomic variety naturally present in a large cell population or occasionally utilizing random mutagenesis to increase this variety.

The ability to precisely create genomic variety in mammalian cells have improved dramatically over the past decade and in the past few years the price has dropped substantially due to the CRISPR/Cas9 technology. E.g. knocking out a gene using CRISPR/Cas9 …

Prediction Of Stable And Transient Expression Of Recombinant Proteins From Cho Cells Based Upon Translational Reprogramming, Charlotte Godfrey

Cell Culture Engineering XV

Translational reprogramming and mRNA translation efficiency influence global protein synthesis, cell proliferation and growth; important parameters in defining recombinant protein expression yields. Reprogramming generally results in a down-regulation of overall global protein synthesis. Polysome profiling is used to analyse mRNA translation via the distribution of ribosomes between monosomes and polysomes, and can be used to investigate translational reprogramming occurring within the cell culture. Here this approach has been applied to investigate the endogenous polysome profiles of host and recombinant Chinese Hamster Ovary (CHO) monoclonal antibody-producing cell lines, and how the profiles change across culture depending on the growth and protein …

Omics Approach For Generating A High-Yield Cho Cell Line Producing Monoclonal Antibodies, Wei Chi, Hsuan-Pu Chen, Dalton Chen, Hsin-Lin Lu, Bor-Shiun Chen, Chao Yi Teng, Chien-I Lin, Hsueh-Lin Lu, Chi-Chen Hsu, Sheng Jie Huang

Cell Culture Engineering XV

Chinese hamster ovary (CHO) cells are extensively used for the industrial manufacture of therapeutic antibodies. Generating high producing cell lines for secretory protein production requires knowing the bottleneck in the cellular machinery for protein expression. Integration site of gene of interest (GOI) is one of the important factors that influence the protein productivity. Even though screening of cells randomly integrated GOI can select high producing cells, the selected cell might not stable due to the chromosome instability. Here, we would like to look for host integration sites where GOI is high yield and stable by screening a single copy integration …

Predictive Engineering Of Cho Cells Using Systems Biology Models, Nathan Lewis

Cell Culture Engineering XV

Decades of bioprocess optimization have resulted in substantial improvements in recombinant protein production. However, some proteins remain difficult to express, and there is an increasing awareness of the need for improved control of critical quality attributes of recombinant protein drugs. To enable cell engineering efforts to enhance protein production and control product quality, we have enumerated the CHO cell parts through genome sequencing efforts,^1,2 and are now providing context to these parts by reconstructing genome-scale networks of the secretory pathway, glycosylation, and metabolism CHO (Figure 1). Using these models, which account for the activities of more than 2000 genes, …