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Barnard GC, Zhou M, Shen A, Yuk IH, Laird MW. Utilizing targeted integration CHO pools to potentially accelerate the GMP manufacturing of monoclonal and bispecific antibodies. Biotechnol Prog 2024; 40:e3399. [PMID: 37874920 DOI: 10.1002/btpr.3399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/03/2023] [Accepted: 10/08/2023] [Indexed: 10/26/2023]
Abstract
Monoclonal antibodies (mAbs) are effective therapeutic agents against many acute infectious diseases including COVID-19, Ebola, RSV, Clostridium difficile, and Anthrax. mAbs can therefore help combat a future pandemic. Unfortunately, mAb development typically takes years, limiting its potential to save lives during a pandemic. Therefore "pandemic mAb" timelines need to be shortened. One acceleration tool is "deferred cloning" and leverages new Chinese hamster ovary (CHO) technology based on targeted gene integration (TI). CHO pools, instead of CHO clones, can be used for Phase I/II clinical material production. A final CHO clone (producing the mAb with a similar product quality profile and preferably with a higher titer) can then be used for Phase III trials and commercial manufacturing. This substitution reduces timelines by ~3 months. We evaluated our novel CHO TI platform to enable deferred cloning. We created four unique CHO pools expressing three unique mAbs (mAb1, mAb2, and mAb3), and a bispecific mAb (BsAb1). We then performed single-cell cloning for mAb1 and mAb2, identifying three high-expressing clones from each pool. CHO pools and clones were inoculated side-by-side in ambr15 bioreactors. CHO pools yielded mAb titers as high as 10.4 g/L (mAb3) and 7.1 g/L (BsAb1). Subcloning yielded CHO clones expressing higher titers relative to the CHO pools while yielding similar product quality profiles. Finally, we showed that CHO TI pools were stable by performing a 3-month cell aging study. In summary, our CHO TI platform can increase the speed to clinic for a future "pandemic mAb."
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Affiliation(s)
- Gavin C Barnard
- Cell Culture and Bioprocess Operations, Genentech, South San Francisco, California, USA
| | - Michelle Zhou
- Cell Culture and Bioprocess Operations, Genentech, South San Francisco, California, USA
| | - Amy Shen
- Cell Culture and Bioprocess Operations, Genentech, South San Francisco, California, USA
| | - Inn H Yuk
- Cell Culture and Bioprocess Operations, Genentech, South San Francisco, California, USA
| | - Michael W Laird
- Cell Culture and Bioprocess Operations, Genentech, South San Francisco, California, USA
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Sinegubova MV, Orlova NA, Vorobiev II. Promoter from Chinese hamster elongation factor-1a gene and Epstein-Barr virus terminal repeats concatemer fragment maintain stable high-level expression of recombinant proteins. PeerJ 2023; 11:e16287. [PMID: 37901457 PMCID: PMC10607201 DOI: 10.7717/peerj.16287] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 09/22/2023] [Indexed: 10/31/2023] Open
Abstract
Background The Chinese hamster ovary (CHO) cell line is the main host for the high-titer production of therapeutic and diagnostic proteins in the biopharmaceutical industry. In most cases, plasmids for efficient protein expression in CHO cells are based on the cytomegalovirus (CMV) promoter. The autologous Chinese hamster eukaryotic translation elongation factor 1α (EEF1A1) promoter is a viable alternative to the CMV promoter in industrial applications. The EEF1A1 promoter and its surrounding DNA regions proved to be effective at maintaining high-level and stable expression of recombinant proteins in CHO cells. EEF1A1-based plasmids' large size can lead to low transfection efficiency and hamper target gene amplification. We hypothesized that an efficient EEF1A1-based expression vector with a long terminal repeat fragment from the Epstein-Barr virus (EBVTR) could be truncated without affecting promoter strength or the long-term stability of target gene expression. Methods We made a series of deletions in the downstream flanking region of the EEF1A1 gene, and then in its upstream flanking region. The resulting plasmids, which coded for the enhanced green fluorescent protein (eGFP), were tested for the level of eGFP expression in the populations of stably transfected CHO DG44 cells and the stability of eGFP expression in the long-term culture in the absence of selection agents. Results It was shown that in the presence of the EBVTR fragment, the entire downstream flanking region of the EEF1A1 gene could be excluded from the plasmid vector. Shortening of the upstream flanking region of the EEF1A1 gene to a length of 2.5 kbp also had no significant effect on the level of eGFP expression or long-term stability. The EBVTR fragment significantly increased expression stability for both the CMV and EEF1A1 promoter-based plasmids, and the expression level drop during the two-month culture was more significant for both CMV promoter-based plasmids. Conclusion Target protein expression stability for the truncated plasmid, based on the EEF1A1 gene and EBVTR fragment, is sufficient for common biopharmaceutical applications, making these plasmid vectors a viable alternative to conventional CMV promoter-based vectors.
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Affiliation(s)
- Maria V. Sinegubova
- Laboratory of Mammalian Cell Bioengineering, Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Nadezhda A. Orlova
- Laboratory of Mammalian Cell Bioengineering, Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Ivan I. Vorobiev
- Laboratory of Mammalian Cell Bioengineering, Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
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3
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Yamaguchi K, Ogawa R, Tsukahara M, Kawakami K. Efficient production of recombinant proteins in suspension CHO cells culture using the Tol2 transposon system coupled with cycloheximide resistance selection. Sci Rep 2023; 13:7628. [PMID: 37165015 PMCID: PMC10172305 DOI: 10.1038/s41598-023-34636-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 05/04/2023] [Indexed: 05/12/2023] Open
Abstract
DNA recombination techniques in mammalian cells has been applied to the production of therapeutic proteins for several decades. To be used for commercial production, established cell lines should stably express target proteins with high productivity and acceptable quality for human use. In the conventional transfection method, the screening process is laborious and time-consuming since superior cell lines had to be selected from an enormous number of transfected cell pools and clonal cell lines with a wide variety of transgene insertion locations. In this study, we demonstrated that the combination of a Tol2 transposon system and cell selection by cycloheximide resistance is an efficient method to express therapeutic proteins, such as human antibody in suspension culture of Chinese hamster ovary cells. The resulting stable cell lines showed constant productivity and cell growth over a long enough cultivation periods for recombinant protein production. We anticipate that this approach will prove widely applicable to protein production in research and development of pharmaceutical products.
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Affiliation(s)
- Keina Yamaguchi
- Laboratory of Molecular and Developmental Biology, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan.
- Bio Process Research and Development Laboratories, Kyowa Kirin Co., Ltd., 100-1 Hagiwara-machi, Takasaki, Gunma, 370-0013, Japan.
| | - Risa Ogawa
- Bio Process Research and Development Laboratories, Kyowa Kirin Co., Ltd., 100-1 Hagiwara-machi, Takasaki, Gunma, 370-0013, Japan
| | - Masayoshi Tsukahara
- Bio Process Research and Development Laboratories, Kyowa Kirin Co., Ltd., 100-1 Hagiwara-machi, Takasaki, Gunma, 370-0013, Japan
| | - Koichi Kawakami
- Laboratory of Molecular and Developmental Biology, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan.
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka, 411-8540, Japan.
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Spahn PN, Zhang X, Hu Q, Lu H, Hamaker NK, Hefzi H, Li S, Kuo CC, Huang Y, Lee JC, Davis AJ, Ly P, Lee KH, Lewis NE. Restoration of DNA repair mitigates genome instability and increases productivity of Chinese hamster ovary cells. Biotechnol Bioeng 2022; 119:963-982. [PMID: 34953085 PMCID: PMC8821244 DOI: 10.1002/bit.28016] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 12/18/2021] [Indexed: 11/11/2022]
Abstract
Chinese hamster ovary (CHO) cells are the primary host for manufacturing of therapeutic proteins. However, productivity loss is a major problem and is associated with genome instability, as chromosomal aberrations reduce transgene copy number and decrease protein expression. We analyzed whole-genome sequencing data from 11 CHO cell lines and found deleterious single-nucleotide variants in DNA repair genes. Comparison with primary Chinese hamster cells confirmed DNA repair to be compromised in CHO. Correction of key DNA repair genes by single-nucleotide variant reversal or expression of intact complementary DNAs successfully improved DNA repair and mitigated karyotypic instability. Moreover, overexpression of intact copies of LIG4 and XRCC6 in a CHO cell line expressing secreted alkaline phosphatase mitigated transgene copy loss and improved protein titer retention. These results show that correction of DNA repair genes yields improvements in genome stability in CHO, and provide new opportunities for cell line development for sustainable protein expression.
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Affiliation(s)
- Philipp N. Spahn
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, The Novo Nordisk Foundation Center for Biosustainability at the University of California, San Diego School of Medicine, San Diego, La Jolla, CA 92093
| | - Xiaolin Zhang
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19711
| | - Qing Hu
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Huiming Lu
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Nathaniel K. Hamaker
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19711
| | - Hooman Hefzi
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
| | - Shangzhong Li
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
| | - Chih-Chung Kuo
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
| | - Yingxiang Huang
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093
| | - Jamie C. Lee
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
| | - Anthony J. Davis
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Peter Ly
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Kelvin H. Lee
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19711, These authors jointly supervised this work: Kelvin H. Lee, , 302-831-0344, Nathan E. Lewis, , 858-997-5844
| | - Nathan E. Lewis
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, The Novo Nordisk Foundation Center for Biosustainability at the University of California, San Diego School of Medicine, San Diego, La Jolla, CA 92093, Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, These authors jointly supervised this work: Kelvin H. Lee, , 302-831-0344, Nathan E. Lewis, , 858-997-5844
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5
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Marx N, Eisenhut P, Weinguny M, Klanert G, Borth N. How to train your cell - Towards controlling phenotypes by harnessing the epigenome of Chinese hamster ovary production cell lines. Biotechnol Adv 2022; 56:107924. [PMID: 35149147 DOI: 10.1016/j.biotechadv.2022.107924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 11/24/2022]
Abstract
Recent advances in omics technologies and the broad availability of big datasets have revolutionized our understanding of Chinese hamster ovary cells in their role as the most prevalent host for production of complex biopharmaceuticals. In consequence, our perception of this "workhorse of the biopharmaceutical industry" has successively shifted from that of a nicely working, but unknown recombinant protein producing black box to a biological system governed by multiple complex regulatory layers that might possibly be harnessed and manipulated at will. Despite the tremendous progress that has been made to characterize CHO cells on various omics levels, our understanding is still far from complete. The well-known inherent genetic plasticity of any immortalized and rapidly dividing cell line also characterizes CHO cells and can lead to problematic instability of recombinant protein production. While the high mutational frequency has been a focus of CHO cell research for decades, the impact of epigenetics and its role in differential gene expression has only recently been addressed. In this review we provide an overview about the current understanding of epigenetic regulation in CHO cells and discuss its significance for shaping the cell's phenotype. We also look into current state-of-the-art technology that can be applied to harness and manipulate the epigenetic network so as to nudge CHO cells towards a specific phenotype. Here, we revise current strategies on site-directed integration and random as well as targeted epigenome modifications. Finally, we address open questions that need to be investigated to exploit the full repertoire of fine-tuned control of multiplexed gene expression using epigenetic and systems biology tools.
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Affiliation(s)
- Nicolas Marx
- University of Natural Resources and Life Sciences, Vienna, Austria
| | - Peter Eisenhut
- Austrian Centre for Industrial Biotechnology GmbH, Vienna, Austria
| | - Marcus Weinguny
- University of Natural Resources and Life Sciences, Vienna, Austria; Austrian Centre for Industrial Biotechnology GmbH, Vienna, Austria
| | - Gerald Klanert
- Austrian Centre for Industrial Biotechnology GmbH, Vienna, Austria
| | - Nicole Borth
- University of Natural Resources and Life Sciences, Vienna, Austria; Austrian Centre for Industrial Biotechnology GmbH, Vienna, Austria.
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Effects of ubiquitous chromatin opening element (UCOE) on recombinant anti-TNFα antibody production and expression stability in CHO-DG44 cells. Cytotechnology 2022; 74:31-49. [PMID: 35185284 PMCID: PMC8817031 DOI: 10.1007/s10616-021-00503-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/17/2021] [Indexed: 02/03/2023] Open
Abstract
To date, the production of antibodies (mAbs) usually faces the risks of transgene expression reduction and instability, especially after long-time culture. The inclusion of ubiquitous chromatin opening element (UCOE) into expression vectors was reported to enhance protein production and maintain transgene expression stability in CHO cell lines. Thus, we investigate the effects of UCOE on recombinant monoclonal anti-TNFα antibody (mAbTNFα) production and expression stability in CHO-DG44 cells. In our study, non-UCOE and UCOE-based vectors encoding mAbTNFα were constructed and introduced into the CHO-DG44 cells. Cell pools and single-cell clones were obtained by selecting transfected cells with G418, amplifying them by treatment with methotrexate (MTX), and isolating them by limiting dilution. The effects of UCOE on mAb production and stable transgene expression in transfected cells were analyzed via the correlation between mAb yields and mRNA expression level variations, and gene copy number changes. The UCOE pool exhibited higher mAb yield compared to non-UCOE pool. The UCOE was associated with higher transgene transcriptional activity, leading to improvement of mAb production after MTX-mediated gene amplification. The incorporation of UCOE generated cells allowed isolation of greater numbers of positive clones with higher expression. Despite the slightly decreased mAb yield, UCOE clones still retain stable long-term expression in the absence of selective pressure, which was explained by the loss of transgene copies rather than due to the decline of transcriptional activity. In addition, the purified mAb had primary chemical and biological characteristics similar to those of adalimumab. The results showed that the incorporation of UCOE within vectors provides significant advantages in the generation of high-producing clones, enhancement of mAb production, and improvement of gene expression stability.
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7
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Altamura R, Doshi J, Benenson Y. Rational design and construction of multi-copy biomanufacturing islands in mammalian cells. Nucleic Acids Res 2022; 50:561-578. [PMID: 34893882 PMCID: PMC8754653 DOI: 10.1093/nar/gkab1214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 11/21/2021] [Accepted: 11/26/2021] [Indexed: 11/14/2022] Open
Abstract
Cell line development is a critical step in the establishment of a biopharmaceutical manufacturing process. Current protocols rely on random transgene integration and amplification. Due to considerable variability in transgene integration profiles, this workflow results in laborious screening campaigns before stable producers can be identified. Alternative approaches for transgene dosage increase and integration are therefore highly desirable. In this study, we present a novel strategy for the rapid design, construction, and genomic integration of engineered multiple-copy gene constructs consisting of up to 10 gene expression cassettes. Key to this strategy is the diversification, at the sequence level, of the individual gene cassettes without altering their protein products. We show a computational workflow for coding and regulatory sequence diversification and optimization followed by experimental assembly of up to nine gene copies and a sentinel reporter on a contiguous scaffold. Transient transfections in CHO cells indicates that protein expression increases with the gene copy number on the scaffold. Further, we stably integrate these cassettes into a pre-validated genomic locus. Altogether, our findings point to the feasibility of engineering a fully mapped multi-copy recombinant protein 'production island' in a mammalian cell line with greatly reduced screening effort, improved stability, and predictable product titers.
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Affiliation(s)
- Raffaele Altamura
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel, 4058, Switzerland
| | - Jiten Doshi
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel, 4058, Switzerland
| | - Yaakov Benenson
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel, 4058, Switzerland
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8
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Marx N, Dhiman H, Schmieder V, Freire CM, Nguyen LN, Klanert G, Borth N. Enhanced targeted DNA methylation of the CMV and endogenous promoters with dCas9-DNMT3A3L entails distinct subsequent histone modification changes in CHO cells. Metab Eng 2021; 66:268-282. [PMID: 33965614 DOI: 10.1016/j.ymben.2021.04.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/02/2021] [Accepted: 04/22/2021] [Indexed: 01/08/2023]
Abstract
With the emergence of new CRISPR/dCas9 tools that enable site specific modulation of DNA methylation and histone modifications, more detailed investigations of the contribution of epigenetic regulation to the precise phenotype of cells in culture, including recombinant production subclones, is now possible. These also allow a wide range of applications in metabolic engineering once the impact of such epigenetic modifications on the chromatin state is available. In this study, enhanced DNA methylation tools were targeted to a recombinant viral promoter (CMV), an endogenous promoter that is silenced in its native state in CHO cells, but had been reactivated previously (β-galactoside α-2,6-sialyltransferase 1) and an active endogenous promoter (α-1,6-fucosyltransferase), respectively. Comparative ChIP-analysis of histone modifications revealed a general loss of active promoter histone marks and the acquisition of distinct repressive heterochromatin marks after targeted methylation. On the other hand, targeted demethylation resulted in autologous acquisition of active promoter histone marks and loss of repressive heterochromatin marks. These data suggest that DNA methylation directs the removal or deposition of specific histone marks associated with either active, poised or silenced chromatin. Moreover, we show that de novo methylation of the CMV promoter results in reduced transgene expression in CHO cells. Although targeted DNA methylation is not efficient, the transgene is repressed, thus offering an explanation for seemingly conflicting reports about the source of CMV promoter instability in CHO cells. Importantly, modulation of epigenetic marks enables to nudge the cell into a specific gene expression pattern or phenotype, which is stabilized in the cell by autologous addition of further epigenetic marks. Such engineering strategies have the added advantage of being reversible and potentially tunable to not only turn on or off a targeted gene, but also to achieve the setting of a desirable expression level.
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Affiliation(s)
- Nicolas Marx
- BOKU University of Natural Resources and Life Sciences, Vienna, Austria; Austrian Center for Industrial Biotechnology GmbH, Vienna, Austria
| | - Heena Dhiman
- BOKU University of Natural Resources and Life Sciences, Vienna, Austria; Austrian Center for Industrial Biotechnology GmbH, Vienna, Austria
| | - Valerie Schmieder
- BOKU University of Natural Resources and Life Sciences, Vienna, Austria; Austrian Center for Industrial Biotechnology GmbH, Vienna, Austria
| | | | - Ly Ngoc Nguyen
- BOKU University of Natural Resources and Life Sciences, Vienna, Austria; Austrian Center for Industrial Biotechnology GmbH, Vienna, Austria
| | - Gerald Klanert
- Austrian Center for Industrial Biotechnology GmbH, Vienna, Austria
| | - Nicole Borth
- BOKU University of Natural Resources and Life Sciences, Vienna, Austria; Austrian Center for Industrial Biotechnology GmbH, Vienna, Austria.
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9
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Baik JY, Han HJ, Lee KH. DNA Double-Strand Breaks Affect Chromosomal Rearrangements during Methotrexate-Mediated Gene Amplification in Chinese Hamster Ovary Cells. Pharmaceutics 2021; 13:pharmaceutics13030376. [PMID: 33809068 PMCID: PMC8000239 DOI: 10.3390/pharmaceutics13030376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/28/2021] [Accepted: 03/05/2021] [Indexed: 11/16/2022] Open
Abstract
Methotrexate (MTX)-mediated gene amplification has been widely used in Chinese hamster ovary (CHO) cells for the biomanufacturing of therapeutic proteins. Although many studies have reported chromosomal instability and extensive chromosomal rearrangements in MTX-mediated gene-amplified cells, which may be associated with cell line instability issues, the mechanisms of chromosomal rearrangement formation remain poorly understood. We tested the impact of DNA double-strand breaks (DSBs) on chromosomal rearrangements using bleomycin, a DSB-inducing reagent. Bleomycin-treated CHO-DUK cells, which are one of the host cell lines deficient in dihydrofolate reductase (Dhfr) activity, exhibited a substantial number of cells containing radial formations or non-radial formations with chromosomal rearrangements, suggesting that DSBs may be associated with chromosomal rearrangements. To confirm the causes of DSBs during gene amplification, we tested the effects of MTX treatment and the removal of nucleotide base precursors on DSB formation in Dhfr-deficient (i.e., CHO-DUK) and Dhfr-expressing (i.e., CHO-K1) cells. Immunocytochemistry demonstrated that MTX treatment did not induce DSBs per se, but a nucleotide shortage caused by the MTX-mediated inhibition of Dhfr activity resulted in DSBs. Our data suggest that a nucleotide shortage caused by MTX-mediated Dhfr inhibition in production cell lines is the primary cause of a marked increase in DSBs, resulting in extensive chromosomal rearrangements after gene amplification processes.
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Affiliation(s)
- Jong Youn Baik
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, USA
- Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
- Department of Biological Engineering, Inha University, Incheon 22212, Korea;
- Correspondence: (J.Y.B.); (K.H.L.); Tel.: +82-32-860-7513 (J.Y.B.); +1-302-831-0344 (K.H.L.)
| | - Hye-Jin Han
- Department of Biological Engineering, Inha University, Incheon 22212, Korea;
| | - Kelvin H. Lee
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, USA
- Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
- Correspondence: (J.Y.B.); (K.H.L.); Tel.: +82-32-860-7513 (J.Y.B.); +1-302-831-0344 (K.H.L.)
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11
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Fluorescence-assisted sequential insertion of transgenes (FASIT): an approach for increasing specific productivity in mammalian cells. Sci Rep 2020; 10:12840. [PMID: 32732973 PMCID: PMC7392891 DOI: 10.1038/s41598-020-69709-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 07/16/2020] [Indexed: 11/08/2022] Open
Abstract
Currently, the generation of cell lines for the production of recombinant proteins has the limitation of unstable gene expression due to the repeat-induced gene silencing or the loss of transgene copies resulting from recombination events. In this work, we developed a new strategy based on the sequential insertion of transgenes for generating stable clones producing high levels of a chimeric human follicle-stimulating hormone (hscFSH). Gene insertion was done by transducing HEK-293 cells with a lentiviral vector containing a bicistronic transcriptional unit for expressing hscFSH and GFP genes. Clone selection was performed by flow cytometry coupled to cell sorting, and the GFP gene was further removed by CRE-mediated site-specific recombination. High-producing clones of hscFSH were obtained after three rounds of lentiviral transduction. Expression levels increased in a step-wise manner from 7 to 23 pg/cell/day, with a relatively constant rate of 7 pg/cell/day in each round of transduction. The GFP gene was successfully removed from the cell genome without disturbing the hscFSH gene expression. Clones generated using this approach showed stable expression levels for more than two years. This is the first report describing the sequential insertion of transgenes as an alternative for increasing the expression levels of transformed cell lines. The methodology described here could notably impact on biotechnological industry by improving the capacity of mammalian cells to produce biopharmaceuticals.
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Lin PC, Chan KF, Kiess IA, Tan J, Shahreel W, Wong SY, Song Z. Attenuated glutamine synthetase as a selection marker in CHO cells to efficiently isolate highly productive stable cells for the production of antibodies and other biologics. MAbs 2019; 11:965-976. [PMID: 31043114 PMCID: PMC6601560 DOI: 10.1080/19420862.2019.1612690] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Chinese hamster ovary (CHO) cells are the biopharmaceutical industry’s primary means of manufacturing therapeutic proteins, including monoclonal antibodies. The major challenge in cell line development for the production of recombinant biopharmaceuticals lies in generating and isolating rare high-producing stable clones, amongst thousands of low-producing or unstable clones, in a short period of time. One approach to accomplish this is to use the glutamine synthetase (GS) selection system, together with the GS inhibitor, methionine sulfoximine (MSX). However, MSX can only increase protein productivity to a limited extent. Often productivity will drop when MSX is removed from the system. We evaluated a congenital GS mutation, R324C, which causes glutamine deficiency in human as an attenuated selection marker for CHO cell line generation. We also created a panel of GS mutants with diminished GS activity. Our results demonstrated that using attenuated GS mutants as selection markers significantly increased antibody production of stably transfected pools. Furthermore, these stably transfected pools sustained high productivity levels for an extended period of time, whereas cells transfected with wild-type GS lost considerable protein productivity over time, particularly after MSX was removed. In summary, the use of attenuated GS as a selection marker in CHO cell line development bypasses the need for MSX, and generates stable clones with significantly higher antibody productivity.Abbreviations: CHO: Chinese hamster ovary; CMV: Cytomegalovirus; DHFR: Dihydrofolate reductase; GFP: Green fluorescent protein; GOI: gene-of-interest; GS: Glutamine synthetase; IRES: internal ribosomal entry site; MSX: Methionine sulfoximine; MTX: Methotrexate; psGS: pseudoGS; RVDs: Repeated variable di-residues; TALENs: transcription activator-like effector nucleases; VCD: Viable cell density; ZFNs: zinc finger nucleases.
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Affiliation(s)
- Pao-Chun Lin
- a Bioprocessing Technology Institute, Agency for Science , Technology and Research (A*STAR) , Singapore
| | - Kah Fai Chan
- a Bioprocessing Technology Institute, Agency for Science , Technology and Research (A*STAR) , Singapore
| | - Irene A Kiess
- a Bioprocessing Technology Institute, Agency for Science , Technology and Research (A*STAR) , Singapore
| | - Joselyn Tan
- a Bioprocessing Technology Institute, Agency for Science , Technology and Research (A*STAR) , Singapore
| | - Wahyu Shahreel
- a Bioprocessing Technology Institute, Agency for Science , Technology and Research (A*STAR) , Singapore
| | - Sze-Yue Wong
- a Bioprocessing Technology Institute, Agency for Science , Technology and Research (A*STAR) , Singapore
| | - Zhiwei Song
- a Bioprocessing Technology Institute, Agency for Science , Technology and Research (A*STAR) , Singapore.,b Department of Biochemistry , Yong Loo Lin School of Medicine, National University of Singapore , Singapore
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13
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Marx N, Grünwald-Gruber C, Bydlinski N, Dhiman H, Ngoc Nguyen L, Klanert G, Borth N. CRISPR-Based Targeted Epigenetic Editing Enables Gene Expression Modulation of the Silenced Beta-Galactoside Alpha-2,6-Sialyltransferase 1 in CHO Cells. Biotechnol J 2018; 13:e1700217. [DOI: 10.1002/biot.201700217] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/01/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Nicolas Marx
- Department of Biotechnology; BOKU University of Natural Resources and Life Sciences; Muthgasse 18 1190 Vienna Austria
- Austrian Centre of Industrial Biotechnology GmbH; Graz Austria
| | - Clemens Grünwald-Gruber
- Department of Biotechnology; BOKU University of Natural Resources and Life Sciences; Muthgasse 18 1190 Vienna Austria
| | - Nina Bydlinski
- Department of Biotechnology; BOKU University of Natural Resources and Life Sciences; Muthgasse 18 1190 Vienna Austria
| | - Heena Dhiman
- Department of Biotechnology; BOKU University of Natural Resources and Life Sciences; Muthgasse 18 1190 Vienna Austria
- Austrian Centre of Industrial Biotechnology GmbH; Graz Austria
| | - Ly Ngoc Nguyen
- Department of Biotechnology; BOKU University of Natural Resources and Life Sciences; Muthgasse 18 1190 Vienna Austria
- Austrian Centre of Industrial Biotechnology GmbH; Graz Austria
| | - Gerald Klanert
- Austrian Centre of Industrial Biotechnology GmbH; Graz Austria
| | - Nicole Borth
- Department of Biotechnology; BOKU University of Natural Resources and Life Sciences; Muthgasse 18 1190 Vienna Austria
- Austrian Centre of Industrial Biotechnology GmbH; Graz Austria
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14
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Noh SM, Shin S, Lee GM. Comprehensive characterization of glutamine synthetase-mediated selection for the establishment of recombinant CHO cells producing monoclonal antibodies. Sci Rep 2018; 8:5361. [PMID: 29599455 PMCID: PMC5876325 DOI: 10.1038/s41598-018-23720-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/18/2018] [Indexed: 12/16/2022] Open
Abstract
To characterize a glutamine synthetase (GS)-based selection system, monoclonal antibody (mAb) producing recombinant CHO cell clones were generated by a single round of selection at various methionine sulfoximine (MSX) concentrations (0, 25, and 50 μM) using two different host cell lines (CHO-K1 and GS-knockout CHO). Regardless of the host cell lines used, the clones selected at 50 μM MSX had the lowest average specific growth rate and the highest average specific production rates of toxic metabolic wastes, lactate and ammonia. Unlike CHO-K1, high producing clones could be generated in the absence of MSX using GS-knockout CHO with an improved selection stringency. Regardless of the host cell lines used, the clones selected at various MSX concentrations showed no significant difference in the GS, heavy chain, and light chain gene copies (P > 0.05). Furthermore, there was no correlation between the specific mAb productivity and these three gene copies (R2 ≤ 0.012). Taken together, GS-mediated gene amplification does not occur in a single round of selection at a MSX concentration up to 50 μM. The use of the GS-knockout CHO host cell line facilitates the rapid generation of high producing clones with reduced production of lactate and ammonia in the absence of MSX.
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Affiliation(s)
- Soo Min Noh
- Department of Biological Sciences, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Seunghyeon Shin
- Department of Biological Sciences, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Gyun Min Lee
- Department of Biological Sciences, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea. .,The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark.
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An IRES-Mediated Tricistronic Vector for Efficient Generation of Stable, High-Level Monoclonal Antibody Producing CHO DG44 Cell Lines. Methods Mol Biol 2018; 1827:335-349. [PMID: 30196505 DOI: 10.1007/978-1-4939-8648-4_17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The generation of stable, high-level monoclonal antibody (mAb) producing cell lines remains a major challenge in biopharmaceutical industry. The commonly used plasmid vectors for mAb expression, which express light chain (LC), heavy chain (HC), and selection marker genes on separate vectors or via multiple promoters on a single vector, are not able to accurately control the ratio of LC over HC expression and tend to result in non-expressing clones. To overcome these issues, we have developed a tricistronic vector using two internal ribosome entry sites (IRES) to express the LC, HC, and dihydrofolate reductase (DHFR) selection marker genes in one transcript. In this tricistronic vector, the three genes are under the control of a hapten-modified human cytomegalovirus (hCMV) promoter containing a core CpG island element (IE) to enhance the production stability. The LC gene is arranged as the first cistron followed by a wild-type IRES to control the HC expression. Such design expresses excess LC polypeptides which enhance mAb expression level and reduce aggregate. A mutated IRES with attenuated strength is applied on DHFR to reduce its expression for enhancing the stringency of selection for high producers. This vector allows easy generation of stable, high mAb producing CHO DG44 pools and clones for antibody development and manufacturing.
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16
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Yeo JHM, Ho SCL, Mariati M, Koh E, Tay SJ, Woen S, Zhang P, Yang Y. Optimized Selection Marker and CHO Host Cell Combinations for Generating High Monoclonal Antibody Producing Cell Lines. Biotechnol J 2017; 12. [DOI: 10.1002/biot.201700175] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 09/13/2017] [Indexed: 12/29/2022]
Affiliation(s)
- Jessna H. M. Yeo
- Bioprocessing Technology Institute; Agency for Science; Technology and Research (A*STAR) Singapore Singapore
| | - Steven C. L. Ho
- Bioprocessing Technology Institute; Agency for Science; Technology and Research (A*STAR) Singapore Singapore
| | - Mariati Mariati
- Bioprocessing Technology Institute; Agency for Science; Technology and Research (A*STAR) Singapore Singapore
| | - Esther Koh
- Bioprocessing Technology Institute; Agency for Science; Technology and Research (A*STAR) Singapore Singapore
| | - Shi Jie Tay
- Bioprocessing Technology Institute; Agency for Science; Technology and Research (A*STAR) Singapore Singapore
| | - Susanto Woen
- Bioprocessing Technology Institute; Agency for Science; Technology and Research (A*STAR) Singapore Singapore
| | - Peiqing Zhang
- Bioprocessing Technology Institute; Agency for Science; Technology and Research (A*STAR) Singapore Singapore
| | - Yuansheng Yang
- Bioprocessing Technology Institute; Agency for Science; Technology and Research (A*STAR) Singapore Singapore
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17
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Baik JY, Lee KH. A framework to quantify karyotype variation associated with CHO cell line instability at a single-cell level. Biotechnol Bioeng 2017; 114:1045-1053. [PMID: 27922175 DOI: 10.1002/bit.26231] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 09/22/2016] [Accepted: 11/28/2016] [Indexed: 01/21/2023]
Abstract
Chinese hamster ovary (CHO) cells, the major mammalian host cells for biomanufacturing of therapeutic proteins, have been extensively investigated to enhance productivity and product quality. However, cell line instability resulting in unexpected changes in productivity or product quality continues to be a challenge. Based on previous reports about causes and characteristics of production instability, we hypothesized that chromosomal rearrangements due to genomic instability are associated with production instability and that these events can be characterized. We developed a production instability model using secreted alkaline phosphatase (SEAP)-expressing CHO cells (CHO-SEAP) as well as a framework to quantify chromosomal rearrangements by karyotyping. In the absence of methotrexate (MTX), CHO-SEAP cells exhibited a slightly increased growth rate, a significantly decreased specific productivity, and changes in the chromosomal rearrangement ratio of seven chromosomes. In contrast, when MTX was re-introduced, the growth rate and SEAP productivity reversed to the initial values, demonstrating the reversibility of production instability in CHO-SEAP cells. Fluorescence in situ hybridization analysis identified that the SEAP genes were incorporated in the chromosomal rearrangement (insertion) part of the der(Z9) chromosome. Karyotype analysis indicated that the insertion ratio of the der(Z9) chromosome decreased in the CHO-SEAP cells grown without MTX, demonstrating a correlation between chromosomal rearrangement and production instability. Our results support a mechanism for production instability, wherein a randomly generated chromosomal rearrangement (or genotype) results in cells with a growth advantage that is also associated with non (or low)-producing traits. As a result, the non-producing cells grow faster and thereby outgrow the producing population. Biotechnol. Bioeng. 2017;114: 1045-1053. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Jong Youn Baik
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, 19716.,Delaware Biotechnology Institute, University of Delaware, 15 Innovation Way, Newark, Delaware, 19711
| | - Kelvin H Lee
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, 19716.,Delaware Biotechnology Institute, University of Delaware, 15 Innovation Way, Newark, Delaware, 19711
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18
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Kent JA, Bommaraju TV, Barnicki SD, Kyung YS, Zhang GG. Industrial Production of Therapeutic Proteins: Cell Lines, Cell Culture, and Purification. HANDBOOK OF INDUSTRIAL CHEMISTRY AND BIOTECHNOLOGY 2017. [PMCID: PMC7121293 DOI: 10.1007/978-3-319-52287-6_29] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
A central pillar of the biotechnology and pharmaceutical industries continues to be the development of biological drug products manufactured from engineered mammalian cell lines. Since the hugely successful launch of human tissue plasminogen activator in 1987 and erythropoietin in 1988, the biopharmaceutical market has grown immensely. In 2014, biotherapeutics made up a significant portion of global drug sales as 7 of the top 10 and 21 of top 50 selling pharmaceuticals in the world were biologics with over US$100 billion in global sales (Table 1, [1]).
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19
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Lengthening of high-yield production levels of monoclonal antibody-producing Chinese hamster ovary cells by downregulation of breast cancer 1. J Biosci Bioeng 2017; 123:382-389. [DOI: 10.1016/j.jbiosc.2016.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 09/12/2016] [Accepted: 09/13/2016] [Indexed: 11/19/2022]
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20
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Javaran VJ, Shafeinia A, Javaran MJ, Gojani EG, Mirzaee M. Transient expression of recombinant tissue plasminogen activator (rt-PA) gene in cucurbit plants using viral vector. Biotechnol Lett 2017; 39:607-612. [PMID: 28091772 DOI: 10.1007/s10529-017-2285-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 01/04/2017] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To use a transient expression system to express a truncated human tissue plasminogen activator (K2S) gene in cucurbit plants. RESULTS The recombinant tissue plasminogen activator protein (K2S form) was expressed in active form in cucurbit plants. Its molecular weight was 43 kDa. The plant-derived rt-PA was determined using goat anti-rabbit antibody by western blotting. Among the infected lines, the highest expression of rt-PA was 62 ng/100 mg per leaf tissue as measured by ELISA. The enzymatic activity of the plant-derived rt-PA was 0.8 IU/ml. CONCLUSIONS The K25 form of rt-PA was expressed for the first time using the viral expression system. Plant-derived rt-PA showed similar potency to commercially-available PA.
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Affiliation(s)
- Vahid Jalali Javaran
- Department of Biotechnology, Ramin University of Agriculture and Natural Resources, Ahwaz, 63417-711, Iran
| | - Alireza Shafeinia
- Department of Biotechnology, Ramin University of Agriculture and Natural Resources, Ahwaz, 63417-711, Iran
| | | | - Esmaeil Ghasemi Gojani
- Department of Biotechnology, Ramin University of Agriculture and Natural Resources, Ahwaz, 63417-711, Iran
| | - Malihe Mirzaee
- Department of Biotechnology, Tarbiat Modares University, Tehran, 14115-336, Iran
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Tsuruta LR, Lopes dos Santos M, Yeda FP, Okamoto OK, Moro AM. Genetic analyses of Per.C6 cell clones producing a therapeutic monoclonal antibody regarding productivity and long-term stability. Appl Microbiol Biotechnol 2016; 100:10031-10041. [DOI: 10.1007/s00253-016-7841-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/21/2016] [Accepted: 09/07/2016] [Indexed: 11/27/2022]
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22
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Tastanova A, Schulz A, Folcher M, Tolstrup A, Puklowski A, Kaufmann H, Fussenegger M. Overexpression of YY1 increases the protein production in mammalian cells. J Biotechnol 2016; 219:72-85. [DOI: 10.1016/j.jbiotec.2015.12.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 12/02/2015] [Accepted: 12/09/2015] [Indexed: 01/07/2023]
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23
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Betts Z, Dickson AJ. Ubiquitous Chromatin Opening Elements (UCOEs) effect on transgene position and expression stability in CHO cells following methotrexate (MTX) amplification. Biotechnol J 2016; 11:554-64. [DOI: 10.1002/biot.201500159] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 08/30/2015] [Accepted: 12/02/2015] [Indexed: 11/12/2022]
Affiliation(s)
- Zeynep Betts
- The University of Manchester, Faculty of Life Sciences, Michael Smith Building; Manchester United Kingdom
| | - Alan J. Dickson
- The University of Manchester, Faculty of Life Sciences, Michael Smith Building; Manchester United Kingdom
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24
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Zieliński M, Wójtowicz-Krawiec A, Mikiewicz D, Kęsik-Brodacka M, Cecuda-Adamczewska V, Marciniak-Rusek A, Sokołowska I, Łukasiewicz N, Gurba L, Odrowąż-Sypniewski M, Baran P, Płucienniczak G, Płucienniczak A, Borowicz P, Szewczyk B. Expression of recombinant human bifunctional peptidylglycine α-amidating monooxygenase in CHO cells and its use for insulin analogue modification. Protein Expr Purif 2015; 119:102-9. [PMID: 26614892 DOI: 10.1016/j.pep.2015.11.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 11/16/2015] [Accepted: 11/18/2015] [Indexed: 10/22/2022]
Abstract
The availability of catalytically active peptidylglycine α-amidating monooxygenase (PAM) should provide the means to examine its potential use for the chemienzymatic synthesis of bioactive peptides for the purpose of pharmacological studies. Hypoglycemic activity is one of the most important features of insulin derivatives. Insulin glargine amide was found to show a time/effect profile which is distinctly more flat and thus more advantageous than insulin glargine itself. The aim of the study was to obtain recombinant PAM and use it for insulin analogue amidation. We stably expressed a recombinant PAM in CHO dhfr-cells in culture. Recombinant PAM was partially purified by fractional ammonium sulphate precipitation and ion-exchange chromatography. The enzyme was used to modify glycine-extended A22(G)-B31(K)-B32(R) human insulin analogue (GKR). Alpha-amidated insulin was analyzed by HPLC and mass spectrometry. Hypoglycemic activity of amidated and non-amidated insulin was compared. The pharmacodynamic effect was based on glucose concentration measurement in Wistar rats with hyperglycemia induced by streptozotocin. The overall glycemic profile up to 36 h was evaluated after subcutaneous single dosing at a range of 2.5-7.5 U/kg b.w. The experiment on rats confirmed with a statistical significance (P < 0.05) hypoglycemic activity of GKR-NH2 in comparison to a control group receiving 0.9% NaCl. Characteristics for GKR-NH2 profile was a rather fast beginning of action (0.5-2.0 h) and quite prolonged return to initial values. GKR-NH2 is a candidate for a hypoglycemic drug product in diabetes care. In addition, this work also provides a valuable alternative method for preparing any other recombinant bioactive peptides with C-terminal amidation.
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Affiliation(s)
- Marcin Zieliński
- Institute of Biotechnology and Antibiotics, Starościńska 5, Warszawa 02-516, Poland.
| | | | - Diana Mikiewicz
- Institute of Biotechnology and Antibiotics, Starościńska 5, Warszawa 02-516, Poland
| | | | | | | | - Iwona Sokołowska
- Institute of Biotechnology and Antibiotics, Starościńska 5, Warszawa 02-516, Poland
| | - Natalia Łukasiewicz
- Institute of Biotechnology and Antibiotics, Starościńska 5, Warszawa 02-516, Poland
| | - Lidia Gurba
- Institute of Biotechnology and Antibiotics, Starościńska 5, Warszawa 02-516, Poland
| | | | - Piotr Baran
- Institute of Biotechnology and Antibiotics, Starościńska 5, Warszawa 02-516, Poland
| | | | | | - Piotr Borowicz
- Institute of Biotechnology and Antibiotics, Starościńska 5, Warszawa 02-516, Poland
| | - Bogusław Szewczyk
- Intercollegiate Faculty of Biotechnology of the University of Gdańsk and the Medical University of Gdańsk, Kładki 24, Gdańsk 80-822, Poland
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25
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Jamnikar U, Nikolic P, Belic A, Blas M, Gaser D, Francky A, Laux H, Blejec A, Baebler S, Gruden K. Transcriptome study and identification of potential marker genes related to the stable expression of recombinant proteins in CHO clones. BMC Biotechnol 2015; 15:98. [PMID: 26499110 PMCID: PMC4812793 DOI: 10.1186/s12896-015-0218-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 10/19/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chinese hamster ovary (CHO) cells have become the host of choice for the production of recombinant proteins, due to their capacity for correct protein folding, assembly, and posttranslational modifications. The most widely used system for recombinant proteins is the gene amplification procedure that uses the CHO-Dhfr expression system. However, CHO cells are known to have a very unstable karyotype. This is due to chromosome rearrangements that can arise from translocations and homologous recombination, especially when cells with the CHO-Dhfr expression system are treated with methotrexate hydrate. The present method used in the industry for testing clones for their long-term stability of recombinant protein production is empirical, and it involves their cultivation over extended periods of time prior to the selection of the most suitable clone for further bioprocess development. The aim of the present study was the identification of marker genes that can predict stable expression of recombinant genes in particular clones early in the development stage. RESULTS The transcriptome profiles of CHO clones with stable and unstable recombinant protein production were investigated over 10-weeks of cultivation, using a DNA microarray. We identified 14 genes that were differentially expressed between the stable and unstable clones already at 2 weeks from the beginning of the cultivation. Their expression was validated by reverse-transcription quantitative real-time PCR (RT-qPCR). Furthermore, the k-nearest neighbour algorithm approach shows that the combination of the gene expression patterns of only five of these 14 genes is sufficient to predict stable recombinant protein production in clones in the early phases of cell-line development. CONCLUSIONS The exact molecular mechanisms that cause unstable recombinant protein production are not fully understood. However, the expression profiles of some genes in clones with stable and unstable recombinant protein production allow prediction of such instability early in the cell-line development stage. We have thus developed a proof-of-concept for a novel approach to eliminate unstable clones in the CHO-Dhfr expression system, which saves time and labour-intensive work in cell-line development.
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Affiliation(s)
- Uros Jamnikar
- Sandoz Biopharmaceuticals, Kolodvorska 27, SI-1234, Menges, Slovenia.
| | - Petra Nikolic
- Jozef Stefan Institute, Jamova cesta 39, SI-1000, Ljubljana, Slovenia.
| | - Ales Belic
- Sandoz Biopharmaceuticals, Kolodvorska 27, SI-1234, Menges, Slovenia.
| | - Marjanca Blas
- Sandoz Biopharmaceuticals, Kolodvorska 27, SI-1234, Menges, Slovenia.
| | - Dominik Gaser
- Sandoz Biopharmaceuticals, Kolodvorska 27, SI-1234, Menges, Slovenia.
| | - Andrej Francky
- Sandoz Biopharmaceuticals, Kolodvorska 27, SI-1234, Menges, Slovenia.
| | - Holger Laux
- Novartis Pharma AG, WKL-681.1.08, 4002, Basel, Switzerland.
| | - Andrej Blejec
- National Institute of Biology, Vecna pot 111, SI-1000, Ljubljana, Slovenia.
| | - Spela Baebler
- National Institute of Biology, Vecna pot 111, SI-1000, Ljubljana, Slovenia.
| | - Kristina Gruden
- National Institute of Biology, Vecna pot 111, SI-1000, Ljubljana, Slovenia.
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26
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Betts Z, Dickson AJ. Assessment of UCOE on Recombinant EPO Production and Expression Stability in Amplified Chinese Hamster Ovary Cells. Mol Biotechnol 2015; 57:846-58. [DOI: 10.1007/s12033-015-9877-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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27
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Betts Z, Croxford AS, Dickson AJ. Evaluating the interaction between UCOE and DHFR-linked amplification and stability of recombinant protein expression. Biotechnol Prog 2015; 31:1014-25. [DOI: 10.1002/btpr.2083] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 03/17/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Zeynep Betts
- Faculty of Life Sciences; University of Manchester; Michael Smith Building, Oxford Road Manchester M13 9PT UK
| | - Alexandra S Croxford
- Faculty of Life Sciences; University of Manchester; Michael Smith Building, Oxford Road Manchester M13 9PT UK
| | - Alan J Dickson
- Faculty of Life Sciences; University of Manchester; Michael Smith Building, Oxford Road Manchester M13 9PT UK
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28
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Spencer S, Gugliotta A, Koenitzer J, Hauser H, Wirth D. Stability of single copy transgene expression in CHOK1 cells is affected by histone modifications but not by DNA methylation. J Biotechnol 2015; 195:15-29. [DOI: 10.1016/j.jbiotec.2014.12.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 12/07/2014] [Accepted: 12/11/2014] [Indexed: 12/22/2022]
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29
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Impact of Using Different Promoters and Matrix Attachment Regions on Recombinant Protein Expression Level and Stability in Stably Transfected CHO Cells. Mol Biotechnol 2014; 57:138-44. [DOI: 10.1007/s12033-014-9809-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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30
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Misaghi S, Chang J, Snedecor B. It's time to regulate: coping with product-induced nongenetic clonal instability in CHO cell lines via regulated protein expression. Biotechnol Prog 2014; 30:1432-40. [PMID: 25104235 DOI: 10.1002/btpr.1970] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 06/13/2014] [Indexed: 12/20/2022]
Abstract
Clonal instability and titer loss during Chinese hamster ovary (CHO) cell line development (CLD) has several underlying causes, the most prominent of which are DNA copy number loss and DNA silencing. However, in some cases, clonal instability is due to the toxicity of the therapeutic protein(s) that clones express. Unlike DNA copy number loss, which may occur in some clones or DNA silencing that is prevalent in certain regions of the genome, the hallmark of product induced clonal instability is its manifestation in all the selected clones. To circumvent such product induced clonal instability, we have developed a vector construct that utilizes a regulated protein expression system in which the constitutive expression of the target protein(s) is prevented unless doxycycline is added to the culture. We have then successfully used this system to express, at high titers, an antibody for which constitutive expression results in clonal instability perhaps due to intracellular accumulation of the antibody. Our data shows that unlike the constitutively expressed or continuously induced clones, uninduced clones do not display instability. Furthermore, maintaining the uninduced clones in culture for months or subjecting them to freeze-thaws did not have any effects on their titers. All together, our findings suggest that a regulated expression system could be suitable for production of difficult proteins that trigger instability.
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Affiliation(s)
- Shahram Misaghi
- Dept. of Early Stage Cell Culture, Genentech, Inc, 1 DNA way, South San, Francisco, CA, 94080
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31
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Mariati, Yeo JHM, Koh EYC, Ho SCL, Yang Y. Insertion of core CpG island element into human CMV promoter for enhancing recombinant protein expression stability in CHO cells. Biotechnol Prog 2014; 30:523-34. [DOI: 10.1002/btpr.1919] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 04/02/2014] [Indexed: 01/17/2023]
Affiliation(s)
- Mariati
- Bioprocessing Technology Inst., Agency for Science, Technology and Research (A*STAR); Singapore 138668 Singapore
| | - Jessna H. M. Yeo
- Bioprocessing Technology Inst., Agency for Science, Technology and Research (A*STAR); Singapore 138668 Singapore
| | - Esther Y. C. Koh
- Bioprocessing Technology Inst., Agency for Science, Technology and Research (A*STAR); Singapore 138668 Singapore
| | - Steven C. L. Ho
- Bioprocessing Technology Inst., Agency for Science, Technology and Research (A*STAR); Singapore 138668 Singapore
| | - Yuansheng Yang
- Bioprocessing Technology Inst., Agency for Science, Technology and Research (A*STAR); Singapore 138668 Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University; Singapore 637459 Singapore
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32
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Vishwanathan N, Le H, Jacob NM, Tsao YS, Ng SW, Loo B, Liu Z, Kantardjieff A, Hu WS. Transcriptome dynamics of transgene amplification in Chinese hamster ovary cells. Biotechnol Bioeng 2013; 111:518-28. [DOI: 10.1002/bit.25117] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/16/2013] [Accepted: 09/09/2013] [Indexed: 12/14/2022]
Affiliation(s)
- Nandita Vishwanathan
- Department of Chemical Engineering and Materials Science; University of Minnesota; 421 Washington Avenue S.E. Minneapolis Minnesota 55455-0132
| | - Huong Le
- Department of Chemical Engineering and Materials Science; University of Minnesota; 421 Washington Avenue S.E. Minneapolis Minnesota 55455-0132
| | - Nitya M. Jacob
- Department of Chemical Engineering and Materials Science; University of Minnesota; 421 Washington Avenue S.E. Minneapolis Minnesota 55455-0132
| | | | - Sze-Wai Ng
- Bioprocessing Technology Institute; Singapore Singapore
| | - Bernard Loo
- Bioprocessing Technology Institute; Singapore Singapore
| | - Zhong Liu
- Bioprocess Development; Merck & Co.; Union New Jersey
| | - Anne Kantardjieff
- Department of Chemical Engineering and Materials Science; University of Minnesota; 421 Washington Avenue S.E. Minneapolis Minnesota 55455-0132
| | - Wei-Shou Hu
- Department of Chemical Engineering and Materials Science; University of Minnesota; 421 Washington Avenue S.E. Minneapolis Minnesota 55455-0132
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Abdoli-Nasab M, Jalali-Javaran M, Cusidó RM, Palazón J, Baghizadeh A, Alizadeh H. Expression of the truncated tissue plasminogen activator (K2S) gene in tobacco chloroplast. Mol Biol Rep 2013; 40:5749-58. [PMID: 24114696 DOI: 10.1007/s11033-013-2678-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 09/14/2013] [Indexed: 01/08/2023]
Abstract
As because the plant plastid genome is highly polyploid, the transformation of chloroplasts permits the introduction of thousands of copies of foreign genes per plant cell and generates extraordinarily high levels of recombinant protein. Human tissue-type plasminogen activator is one of the most important pharmaceutical proteins involved in the breakdown of blood clots in brain and heart blood vessels. We report the introduction and expression of the truncated human tissue plasminogen activator (K2S) gene in tobacco chloroplasts. The K2S-containing vector pKCZK2S was successfully transferred to tobacco plastomes using the biolistic delivery procedure. Transplastomic plants were selected on RMOP medium containing spectinomycin (500 mg/l). In order to achieve homoplasmy, several rounds of selection and regeneration were performed. The presence, site-specific integration, homoplasmy, expression and activity assay of the transgene were confirmed in the transplastomic plants by PCR, Southern-blot, RT-PCR, SDS-PAGE, ELISA, Dot-blot, Western-blot and zymography analysis. Our results show that the tissue plasminogen activator (K2S form) protein to be expressed in tobacco chloroplasts in active form.
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Affiliation(s)
- Maryam Abdoli-Nasab
- Department of Plant Breeding & Biotechnology, Faculty of Agriculture, Tarbiat Modares University, P.O. Box 14115-336, Tehran, Iran,
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Freund S, Rath A, Barradas OP, Skerhutt E, Scholz S, Niklas J, Sandig V, Rose T, Heinzle E, Noll T, Pörtner R, Zeng AP, Reichl U. Batch-to-batch variability of two human designer cell lines - AGE1.HN and AGE1.HN.AAT - carried out by different laboratories under defined culture conditions using a mathematical model. Eng Life Sci 2013. [DOI: 10.1002/elsc.201200111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Susann Freund
- Bioprocess Engineering; Max Planck Institute for Dynamics of Complex Technical Systems; Magdeburg Germany
| | - Alexander Rath
- Bioprocess Engineering; Max Planck Institute for Dynamics of Complex Technical Systems; Magdeburg Germany
| | - Oscar Platas Barradas
- Institute of Bioprocess and Biosystems Engineering; Hamburg University of Technology; Hamburg Germany
| | - Eva Skerhutt
- Institute of Cell Culture Technology; University of Bielefeld; Bielefeld Germany
| | - Sebastian Scholz
- Institute of Cell Culture Technology; University of Bielefeld; Bielefeld Germany
| | - Jens Niklas
- Biochemical Engineering Institute; Saarland University; Saarbrücken Germany
| | | | | | - Elmar Heinzle
- Biochemical Engineering Institute; Saarland University; Saarbrücken Germany
| | - Thomas Noll
- Institute of Cell Culture Technology; University of Bielefeld; Bielefeld Germany
| | - Ralf Pörtner
- Institute of Bioprocess and Biosystems Engineering; Hamburg University of Technology; Hamburg Germany
| | - An Ping Zeng
- Institute of Bioprocess and Biosystems Engineering; Hamburg University of Technology; Hamburg Germany
| | - Udo Reichl
- Bioprocess Engineering; Max Planck Institute for Dynamics of Complex Technical Systems; Magdeburg Germany
- Bioprocess Engineering; Otto-von-Guericke University; Magdeburg Germany
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35
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Du Z, Mujacic M, Le K, Caspary G, Nunn H, Heath C, Reddy P. Analysis of heterogeneity and instability of stable mAb-expressing CHO cells. BIOTECHNOL BIOPROC E 2013. [DOI: 10.1007/s12257-012-0577-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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36
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Kober L, Zehe C, Bode J. Optimized signal peptides for the development of high expressing CHO cell lines. Biotechnol Bioeng 2013; 110:1164-73. [DOI: 10.1002/bit.24776] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 10/17/2012] [Accepted: 10/25/2012] [Indexed: 01/12/2023]
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37
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Kim DY, Chaudhry MA, Kennard ML, Jardon MA, Braasch K, Dionne B, Butler M, Piret JM. Fed-batch CHO cell t-PA production and feed glutamine replacement to reduce ammonia production. Biotechnol Prog 2012; 29:165-75. [DOI: 10.1002/btpr.1658] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 10/15/2012] [Indexed: 12/17/2022]
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38
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Generation of a Chinese hamster ovary cell line producing recombinant human glucocerebrosidase. J Biomed Biotechnol 2012; 2012:875383. [PMID: 23091360 PMCID: PMC3471063 DOI: 10.1155/2012/875383] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 06/30/2012] [Accepted: 07/19/2012] [Indexed: 01/11/2023] Open
Abstract
Impaired activity of the lysosomal enzyme glucocerebrosidase (GCR) results in the inherited metabolic disorder known as Gaucher disease. Current treatment consists of enzyme replacement therapy by administration of exogenous GCR. Although effective, it is exceptionally expensive, and patients worldwide have a limited access to this medicine. In Brazil, the public healthcare system provides the drug free of charge for all Gaucher's patients, which reaches the order of $ 84 million per year. However, the production of GCR by public institutions in Brazil would reduce significantly the therapy costs. Here, we describe a robust protocol for the generation of a cell line producing recombinant human GCR. The protein was expressed in CHO-DXB11 (dhfr−) cells after stable transfection and gene amplification with methotrexate. As expected, glycosylated GCR was detected by immunoblotting assay both as cell-associated (~64 and 59 kDa) and secreted (63–69 kDa) form. Analysis of subclones allowed the selection of stable CHO cells producing a secreted functional enzyme, with a calculated productivity of 5.14 pg/cell/day for the highest producer. Although being laborious, traditional methods of screening high-producing recombinant cells may represent a valuable alternative to generate expensive biopharmaceuticals in countries with limited resources.
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39
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Beckmann TF, Krämer O, Klausing S, Heinrich C, Thüte T, Büntemeyer H, Hoffrogge R, Noll T. Effects of high passage cultivation on CHO cells: a global analysis. Appl Microbiol Biotechnol 2012; 94:659-71. [DOI: 10.1007/s00253-011-3806-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 11/27/2011] [Accepted: 11/28/2011] [Indexed: 01/19/2023]
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40
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Jardon MA, Sattha B, Braasch K, Leung AO, Côté HCF, Butler M, Gorski SM, Piret JM. Inhibition of glutamine-dependent autophagy increases t-PA production in CHO cell fed-batch processes. Biotechnol Bioeng 2011; 109:1228-38. [PMID: 22125188 DOI: 10.1002/bit.24393] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 10/06/2011] [Accepted: 11/16/2011] [Indexed: 12/13/2022]
Abstract
Understanding the cellular responses caused by metabolic stress is crucial for the design of robust fed-batch bioprocesses that maximize the expression of recombinant proteins. Chinese hamster ovary cells were investigated in chemically defined, serum-free cultures yielding 10(7) cells/mL and up to 500 mg/L recombinant tissue-plasminogen activator (t-PA). Upon glutamine depletion increased autophagosome formation and autophagic flux were observed, along with decreased proliferation and high viability. Higher lysosomal levels correlated with decreased productivity. Chemical inhibition of autophagy with 3-methyl adenine (3-MA) increased the t-PA yield by 2.8-fold. Autophagy-related MAP1LC3 and LAMP2 mRNA levels increased continuously in all cultures. Analysis of protein quality revealed that 3-MA treatment did not alter glycan antennarity while increasing fucosylation, galactosylation, and sialylation. Taken together, these findings indicate that inhibition of autophagy can considerably increase the yield of biotechnology fed-batch processes, without compromising the glycosylation capacity of cells. Monitoring or genetic engineering of autophagy provides novel avenues to improve the performance of cell culture-based recombinant protein production.
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Affiliation(s)
- Mario A Jardon
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
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41
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Dorai H, Corisdeo S, Ellis D, Kinney C, Chomo M, Hawley-Nelson P, Moore G, Betenbaugh MJ, Ganguly S. Early prediction of instability of chinese hamster ovary cell lines expressing recombinant antibodies and antibody-fusion proteins. Biotechnol Bioeng 2011; 109:1016-30. [DOI: 10.1002/bit.24367] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 09/30/2011] [Accepted: 10/24/2011] [Indexed: 02/03/2023]
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42
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Insight into the roles of hypoxanthine and thydimine on cultivating antibody-producing CHO cells: cell growth, antibody production and long-term stability. Appl Microbiol Biotechnol 2011; 93:169-78. [DOI: 10.1007/s00253-011-3484-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 06/30/2011] [Accepted: 07/13/2011] [Indexed: 12/20/2022]
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43
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Dowd JE, Jubb A, Kwok KE, Piret JM. Optimization and control of perfusion cultures using a viable cell probe and cell specific perfusion rates. Cytotechnology 2011; 42:35-45. [PMID: 19002926 DOI: 10.1023/a:1026192228471] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Consistent perfusion culture production requires reliable cell retention and control of feed rates. An on-line cell probe based on capacitance was used to assay viable biomass concentrations. A constant cell specific perfusion rate controlled medium feed rates with a bioreactor cell concentration of approximately 5 x 10(6) cells mL(-1). Perfusion feeding was automatically adjusted based on the cell concentration signal from the on-line biomass sensor. Cell specific perfusion rates were varied over a range of 0.05 to 0.4 nL cell(-1) day(-1). Pseudo-steady-state bioreactor indices (concentrations, cellular rates and yields) were correlated to cell specific perfusion rates investigated to maximize recombinant protein production from a Chinese hamster ovary cell line. The tissue-type plasminogen activator concentration was maximized ( approximately 40 mg L(-1)) at 0.2 nL cell(-1) day(-1). The volumetric protein productivity ( approximately 60 mg L(-1) day(-1) was maximized above 0.3 nL cell(-1) day(-1). The use of cell specific perfusion rates provided a straightforward basis for controlling, modeling and optimizing perfusion cultures.
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Affiliation(s)
- Jason E Dowd
- Biotechnology Laboratory, University of British Columbia, Vancouver, BC, Canada
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44
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Osterlehner A, Simmeth S, Göpfert U. Promoter methylation and transgene copy numbers predict unstable protein production in recombinant chinese hamster ovary cell lines. Biotechnol Bioeng 2011; 108:2670-81. [DOI: 10.1002/bit.23216] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 04/19/2011] [Accepted: 05/05/2011] [Indexed: 02/06/2023]
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45
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Feng HT, Sim LC, Wan C, Wong NSC, Yang Y. Rapid characterization of protein productivity and production stability of CHO cells by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2011; 25:1407-1412. [PMID: 21504006 DOI: 10.1002/rcm.5011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The biopharmaceutical industry has been in pursuit of strategies which can isolate stable and high-producing cell lines. The whole cell mass spectrometry method by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) is a rapid and simple method for cell characterization based on the differences in the fingerprints of the mass spectra. This work describes how the method was evaluated for the application of screening for stable and high-producing clones from a panel of recombinant Chinese hamster ovary (CHO) cell lines. Detectable m/z values and their relative intensities were collected and processed by partial least squares (PLS). To reduce the errors introduced by the preparation method and spectra noise, high intensity preliminary data was selected and the number of variables introduced was validated by leave-one-out cross-validation. The differences in recombinant protein productivity and titer were revealed by PLS regression with promising results. Partial least-squares discriminant analysis (PLS-DA) was applied to differentiate stable and unstable cell lines as traditional stability testing would require several months involving numerous continuous passages. Results confirmed that the whole cell MALDI-TOF method can be a powerful method for routine monitoring of bioprocesses and study can be further developed by extending the number of the cell lines tested to establish a recombinant cell line database.
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Affiliation(s)
- Hua-tao Feng
- Bioprocessing Technology Institute, A*STAR (Agency for Science, Technology and Research), 20 Biopolis Way, Centros, Singapore 138668.
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46
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Kim M, O'Callaghan PM, Droms KA, James DC. A mechanistic understanding of production instability in CHO cell lines expressing recombinant monoclonal antibodies. Biotechnol Bioeng 2011; 108:2434-46. [PMID: 21538334 DOI: 10.1002/bit.23189] [Citation(s) in RCA: 151] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 04/01/2011] [Accepted: 04/14/2011] [Indexed: 12/13/2022]
Abstract
One of the most significant problems in industrial bioprocessing of recombinant proteins using engineered mammalian cells is the phenomenon of cell line instability, where a production cell line suffers a loss of specific productivity (qP). This phenomenon occurs with unpredictable kinetics and has been widely observed in Chinese hamster ovary (CHO) cell lines and with all commonly used gene expression systems. The underlying causes (both genetic and physiological) and the precise molecular mechanisms underpinning cell line instability have yet to be fully elucidated, although recombinant gene silencing and loss of recombinant gene copies have been shown to cause qP loss. In this work we have investigated the molecular mechanisms underpinning qP instability over long-term sub-culture in CHO cell lines producing recombinant IgG1 and IgG2 monoclonal antibodies (Mab's). We demonstrate that production instability derives from two primary mechanisms: (i) epigenetic--methylation-induced transcriptional silencing of the CMV promoter driving Mab gene transcription and (ii) genetic--progressive loss of recombinant Mab gene copies in a proliferating CHO cell population. We suggest that qP decline resulting from loss of recombinant genes is a consequence of the inherent genetic instability of recombinant CHO cell lines.
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Affiliation(s)
- Minsoo Kim
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin St., Sheffield S1 3JD, UK; telephone: +44-114-222-7505; fax: +44-114-222-7501
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47
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Yang Y, Mariati, Chusainow J, Yap MG. DNA methylation contributes to loss in productivity of monoclonal antibody-producing CHO cell lines. J Biotechnol 2010; 147:180-5. [DOI: 10.1016/j.jbiotec.2010.04.004] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 03/18/2010] [Accepted: 04/11/2010] [Indexed: 11/16/2022]
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48
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Evaluation of Chinese hamster ovary cell stability during repeated batch culture for large-scale antibody production. J Biosci Bioeng 2010; 109:274-80. [DOI: 10.1016/j.jbiosc.2009.09.044] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 09/15/2009] [Accepted: 09/15/2009] [Indexed: 11/18/2022]
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49
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Pilbrough W, Munro TP, Gray P. Intraclonal protein expression heterogeneity in recombinant CHO cells. PLoS One 2009; 4:e8432. [PMID: 20037651 PMCID: PMC2793030 DOI: 10.1371/journal.pone.0008432] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 12/02/2009] [Indexed: 11/19/2022] Open
Abstract
Therapeutic glycoproteins have played a major role in the commercial success of biotechnology in the post-genomic era. But isolating recombinant mammalian cell lines for large-scale production remains costly and time-consuming, due to substantial variation and unpredictable stability of expression amongst transfected cells, requiring extensive clone screening to identify suitable high producers. Streamlining this process is of considerable interest to industry yet the underlying phenomena are still not well understood. Here we examine an antibody-expressing Chinese hamster ovary (CHO) clone at single-cell resolution using flow cytometry and vectors, which couple light and heavy chain transcription to fluorescent markers. Expression variation has traditionally been attributed to genetic heterogeneity arising from random genomic integration of vector DNA. It follows that single cell cloning should yield a homogeneous cell population. We show, in fact, that expression in a clone can be surprisingly heterogeneous (standard deviation 50 to 70% of the mean), approaching the level of variation in mixed transfectant pools, and each antibody chain varies in tandem. Phenotypic variation is fully developed within just 18 days of cloning, yet is not entirely explained by measurement noise, cell size, or the cell cycle. By monitoring the dynamic response of subpopulations and subclones, we show that cells also undergo slow stochastic fluctuations in expression (half-life 2 to 11 generations). Non-genetic diversity may therefore play a greater role in clonal variation than previously thought. This also has unexpected implications for expression stability. Stochastic gene expression noise and selection bias lead to perturbations from steady state at the time of cloning. The resulting transient response as clones reestablish their expression distribution is not ordinarily accounted for but can contribute to declines in median expression over timescales of up to 50 days. Noise minimization may therefore be a novel strategy to reduce apparent expression instability and simplify cell line selection.
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Affiliation(s)
- Warren Pilbrough
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, Queensland, Australia
| | - Trent P. Munro
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, Queensland, Australia
- ACYTE Biotech Pty Ltd, Brisbane, Queensland, Australia
- * E-mail:
| | - Peter Gray
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, Queensland, Australia
- ACYTE Biotech Pty Ltd, Brisbane, Queensland, Australia
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50
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Ng SK, Lin W, Sachdeva R, Wang DI, Yap MG. Vector fragmentation: Characterizing vector integrity in transfected clones by Southern blotting. Biotechnol Prog 2009; 26:11-20. [DOI: 10.1002/btpr.281] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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