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  1. Article ; Online: Combining regulated and constitutive protein expression significantly boosts protein expression by increasing productivity without affecting CHO cell growth.

    Lam, Cynthia / Carver, Joseph / Ng, Domingos / Zhan, Dejin / Tang, Danming / Kandamkalam, Thara / Snedecor, Brad / Barnard, Gavin / Shen, Amy / Misaghi, Shahram

    Biotechnology progress

    2023  Volume 39, Issue 3, Page(s) e3337

    Abstract: Chinese hamster ovary (CHO) cells are commonly used for the expression of therapeutic proteins. To increase the titer output of CHO production cultures either specific productivity (Qp), growth, or both need to be increased. Generally, Qp and growth are ... ...

    Abstract Chinese hamster ovary (CHO) cells are commonly used for the expression of therapeutic proteins. To increase the titer output of CHO production cultures either specific productivity (Qp), growth, or both need to be increased. Generally, Qp and growth are inversely correlated and cell lines with high Qp have slower growth and vice versa. During the cell line development (CLD) process, the faster-growing cells tend to take over the culture and represent the majority of the isolated clones post single cell cloning. In this study, combinations of regulated and constitutive expression systems were used to supertransfect targeted integration (TI) cell lines expressing the same antibody either constitutively or under-regulated expression. Clone screening with a hybrid expression system (inducible + constitutive) allowed identification and selection of higher titer clones under uninduced conditions, without a negative impact on cell growth during clone selection and expansion. Induction of the regulated promoter(s) during the production phase increased the Qp without negatively affecting growth, resulting in approximately twofold higher titers (from 3.5 to 6-7 g/L). This was also confirmed using a 2-site TI host where the gene of interest was expressed inducibly from Site 1 and constitutively from Site 2. Our findings suggest that such a hybrid expression CLD system can be used to increase production titers, providing a novel approach for expression of therapeutic proteins with high titer market demands.
    MeSH term(s) Cricetinae ; Animals ; CHO Cells ; Cricetulus ; Clone Cells ; Antibodies ; Cell Proliferation/genetics ; Recombinant Proteins/genetics
    Chemical Substances Antibodies ; Recombinant Proteins
    Language English
    Publishing date 2023-03-11
    Publishing country United States
    Document type Journal Article
    ZDB-ID 165657-0
    ISSN 1520-6033 ; 8756-7938
    ISSN (online) 1520-6033
    ISSN 8756-7938
    DOI 10.1002/btpr.3337
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Engineered Cytochrome P450-Catalyzed Oxidative Biaryl Coupling Reaction Provides a Scalable Entry into Arylomycin Antibiotics

    Molinaro, Carmela / Kawasaki, Yukie / Wanyoike, George / Nishioka, Taiki / Yamamoto, Tsuyoshi / Snedecor, Brad / Robinson, Sarah J. / Gosselin, Francis

    Journal of the American Chemical Society. 2022 July 29, v. 144, no. 32

    2022  

    Abstract: We report herein the first example of a cytochrome P450-catalyzed oxidative carbon–carbon coupling process for a scalable entry into arylomycin antibiotic cores. Starting from wild-type hydroxylating cytochrome P450 enzymes and engineered Escherichia ... ...

    Abstract We report herein the first example of a cytochrome P450-catalyzed oxidative carbon–carbon coupling process for a scalable entry into arylomycin antibiotic cores. Starting from wild-type hydroxylating cytochrome P450 enzymes and engineered Escherichia coli, a combination of enzyme engineering, random mutagenesis, and optimization of reaction conditions generated a P450 variant that affords the desired arylomycin core 2d in 84% assay yield. Furthermore, this process was demonstrated as a viable route for the production of the arylomycin antibiotic core on the gram scale. Finally, this new entry affords a viable, scalable, and practical route for the synthesis of novel Gram-negative antibiotics.
    Keywords Escherichia coli ; antibiotics ; cytochrome P-450 ; enzymes ; mutagenesis
    Language English
    Dates of publication 2022-0729
    Size p. 14838-14845.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/jacs.2c06019
    Database NAL-Catalogue (AGRICOLA)

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  3. Article ; Online: Preventing pyruvate kinase muscle expression in Chinese hamster ovary cells curbs lactogenic behavior by altering glycolysis, gating pyruvate generation, and increasing pyruvate flux into the TCA cycle.

    Tang, Danming / Sandoval, Wendy / Liu, Peter / Lam, Cynthia / Snedecor, Brad / Misaghi, Shahram

    Biotechnology progress

    2021  Volume 37, Issue 5, Page(s) e3193

    Abstract: Deletion of the pyruvate kinase muscle (PKM) gene, which is involved in conversion of phosphoenolpyruvate to pyruvate, has been shown to curb lactogenic behavior in Chinese hamster ovary (CHO) cells. This study describes the generation of pyruvate kinase ...

    Abstract Deletion of the pyruvate kinase muscle (PKM) gene, which is involved in conversion of phosphoenolpyruvate to pyruvate, has been shown to curb lactogenic behavior in Chinese hamster ovary (CHO) cells. This study describes the generation of pyruvate kinase muscle isoforms 1 and 2 knockout (PKM-KO) and pyruvate kinase muscle isoform-1 knockout (PKM1-KO) CHO host cells to understand metabolic shifts that reduce lactate secretion in these cells. Glucose and amino acids uptake levels in wild-type (WT), PKM-KO, and PKM1-KO stable cell lines, expressing two different antibodies, were analyzed in 14-day fed-batch production assays using different vessels. PKM-KO and PKM1-KO cells consumed more glucose per cell, altered amino acids metabolism, had higher flux of pyruvate into the tricarboxylic acid (TCA) cycle, and as previously shown reduced lactate secretion levels compared with the WT cells. Additionally, both PKM-KO and PKM1-KO cells had higher specific productivity and lower cell growth rates compared with the WT cells. Our findings suggest that rewiring the flux of pyruvate to the TCA cycle by deletion of PKM or PKM1 reduced cell growth and increased specific productivity in CHO cells. Overall, PKM1-KO cells had similar product quality and comparable or better titers relative to the WT cells, hence, targeted deletion of this isoform for curbing lactogenic behavior in CHO cells is suggested.
    MeSH term(s) Animals ; Bioreactors ; CHO Cells ; Carrier Proteins/genetics ; Carrier Proteins/metabolism ; Citric Acid Cycle/physiology ; Cricetinae ; Cricetulus ; Glycolysis ; Membrane Proteins/genetics ; Membrane Proteins/metabolism ; Protein Isoforms/genetics ; Protein Isoforms/metabolism ; Pyruvic Acid/metabolism ; Thyroid Hormones/genetics ; Thyroid Hormones/metabolism ; Thyroid Hormone-Binding Proteins
    Chemical Substances Carrier Proteins ; Membrane Proteins ; Protein Isoforms ; Thyroid Hormones ; Pyruvic Acid (8558G7RUTR)
    Language English
    Publishing date 2021-07-28
    Publishing country United States
    Document type Journal Article
    ZDB-ID 165657-0
    ISSN 1520-6033 ; 8756-7938
    ISSN (online) 1520-6033
    ISSN 8756-7938
    DOI 10.1002/btpr.3193
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Engineered Cytochrome P450-Catalyzed Oxidative Biaryl Coupling Reaction Provides a Scalable Entry into Arylomycin Antibiotics.

    Molinaro, Carmela / Kawasaki, Yukie / Wanyoike, George / Nishioka, Taiki / Yamamoto, Tsuyoshi / Snedecor, Brad / Robinson, Sarah J / Gosselin, Francis

    Journal of the American Chemical Society

    2022  Volume 144, Issue 32, Page(s) 14838–14845

    Abstract: We report herein the first example of a cytochrome P450-catalyzed oxidative carbon-carbon coupling process for a scalable entry into arylomycin antibiotic cores. Starting from wild-type hydroxylating cytochrome P450 enzymes and ... ...

    Abstract We report herein the first example of a cytochrome P450-catalyzed oxidative carbon-carbon coupling process for a scalable entry into arylomycin antibiotic cores. Starting from wild-type hydroxylating cytochrome P450 enzymes and engineered
    MeSH term(s) Anti-Bacterial Agents/pharmacology ; Carbon ; Catalysis ; Cytochrome P-450 Enzyme System/metabolism ; Escherichia coli/metabolism ; Oxidative Stress
    Chemical Substances Anti-Bacterial Agents ; Carbon (7440-44-0) ; Cytochrome P-450 Enzyme System (9035-51-2)
    Language English
    Publishing date 2022-07-29
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/jacs.2c06019
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Bax and Bak knockout apoptosis-resistant Chinese hamster ovary cell lines significantly improve culture viability and titer in intensified fed-batch culture process.

    Tang, Danming / Lam, Cynthia / Bauer, Niels / Auslaender, Simon / Snedecor, Brad / Laird, Michael W / Misaghi, Shahram

    Biotechnology progress

    2022  Volume 38, Issue 2, Page(s) e3228

    Abstract: In the field of therapeutic protein production, process intensification strategies entailing higher starting cell seeding densities, can potentially increase culture productivity, lower cost of goods and improve facility utilization. However, increased ... ...

    Abstract In the field of therapeutic protein production, process intensification strategies entailing higher starting cell seeding densities, can potentially increase culture productivity, lower cost of goods and improve facility utilization. However, increased cell densities often trigger apoptotic cell death at the end of the cell culture process and thus reduce total viable cell count. Apoptosis-resistant Chinese hamster ovary cell lines may offer the possibility to diminish this undesired outcome of the intensified production process. In this study, we have generated and tested Bax/Bak double-knock-out (DKO) apoptosis resistant hosts to express standard and bispecific antibodies, as well as complex molecules in intensified production processes both as pools and single cell clones, and at different scales. In all cases, therapeutic proteins expressed from clones or pools generated from the Bax/Bak DKO hosts showed not only better viability but also enabled extended productivity in the later stages of the 14-day intensified production process. The product qualities of the produced molecules were comparable between Bax/Bak DKO and wild type cells. Overall, we showed that Bax/Bak DKO apoptosis-resistant host cell lines significantly improve viability and volumetric productivity of the intensified production cultures without altering product qualities.
    MeSH term(s) Animals ; Apoptosis/genetics ; Batch Cell Culture Techniques ; CHO Cells ; Cricetinae ; Cricetulus ; bcl-2 Homologous Antagonist-Killer Protein/genetics ; bcl-2-Associated X Protein/genetics
    Chemical Substances bcl-2 Homologous Antagonist-Killer Protein ; bcl-2-Associated X Protein
    Language English
    Publishing date 2022-01-08
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 165657-0
    ISSN 1520-6033 ; 8756-7938
    ISSN (online) 1520-6033
    ISSN 8756-7938
    DOI 10.1002/btpr.3228
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  6. Article ; Online: Activation of the PERK branch of the unfolded protein response during production reduces specific productivity in CHO cells via downregulation of PDGFRa and IRE1a signaling.

    Castellano, Brian M / Tang, Danming / Marsters, Scot / Lam, Cynthia / Liu, Peter / Rose, Christopher M / Sandoval, Wendy / Ashkenazi, Avi / Snedecor, Brad / Misaghi, Shahram

    Biotechnology progress

    2023  Volume 39, Issue 5, Page(s) e3354

    Abstract: During the course of biopharmaceutical production, heterologous protein expression in Chinese hamster ovary (CHO) cells imposes a high proteostatic burden that requires cellular adaptation. To mitigate such burden, cells utilize the unfolded protein ... ...

    Abstract During the course of biopharmaceutical production, heterologous protein expression in Chinese hamster ovary (CHO) cells imposes a high proteostatic burden that requires cellular adaptation. To mitigate such burden, cells utilize the unfolded protein response (UPR), which increases endoplasmic reticulum (ER) capacity to accommodate elevated rates of protein synthesis and folding. In this study, we show that during production the UPR regulates growth factor signaling to modulate growth and protein synthesis. Specifically, the protein kinase R-like ER kinase (PERK) branch of the UPR is responsible for transcriptional down-regulation of platelet-derived growth factor receptor alpha (PDGFRa) and attenuation of the IRE1-alpha (IRE1a) branch of the UPR. PERK knockout (KO) cell lines displayed reduced growth and viability due to higher rates of apoptosis despite having stabilized PDGFRa levels. Knocking out PERK in an apoptosis impaired (Bax/Bak double KO) antibody-expressing cell line prevented apoptotic cell death and revealed that apoptosis was likely triggered by increased ER stress and reactive oxygen species levels in the PERK KO hosts. Our findings suggest that attenuation of IRE1a and PDGFRa signaling by the PERK branch of the UPR reduces ER protein folding capacity and hence specific productivity of CHO cells in order to mitigate UPR and prevent apoptotic cell death. Last, Bax/Bak/PERK triple KO CHO cell lines displayed 2-3 folds higher specific productivity and titer (up to 8 g/L), suggesting that modulation of PERK signaling during production processes can greatly improve specific productivity in CHO cells.
    Language English
    Publishing date 2023-05-10
    Publishing country United States
    Document type Journal Article
    ZDB-ID 165657-0
    ISSN 1520-6033 ; 8756-7938
    ISSN (online) 1520-6033
    ISSN 8756-7938
    DOI 10.1002/btpr.3354
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  7. Article: Insulin degrading enzyme (IDE) expressed by Chinese hamster ovary (CHO) cells is responsible for degradation of insulin in culture media

    Louie, Salina / Lakkyreddy, Jayanthi / Castellano, Brian M / Haley, Benjamin / Nguyen Dang, Anh / Lam, Cynthia / Tang, Danming / Lang, Steven / Snedecor, Brad / Misaghi, Shahram

    Journal of biotechnology. 2020 Aug. 20, v. 320

    2020  

    Abstract: Chinese hamster ovary (CHO) cells cultured in serum-free chemically-defined media (CDM) are used for manufacturing of therapeutic proteins. Growth factors, such as insulin are commonly utilized in manufacturing platforms to enhance CHO cell viability and ...

    Abstract Chinese hamster ovary (CHO) cells cultured in serum-free chemically-defined media (CDM) are used for manufacturing of therapeutic proteins. Growth factors, such as insulin are commonly utilized in manufacturing platforms to enhance CHO cell viability and growth. Here we report that insulin is degraded in the culture media over time mainly due to the activity of the insulin degrading enzyme (IDE). Insulin degradation was faster in cell lines that released more IDE, which negatively impacted cell growth and in turn, production titers. Deletion of the IDE gene in a representative CHO cell line nearly abolished insulin degradation in seed train and end-of-production media. In summary, our data suggests that selecting cell lines that have lower IDE expression or targeted-deletion of the IDE gene can improve culture viability and growth for insulin-dependent CHO production platforms.
    Keywords Cricetulus griseus ; biotechnology ; cell growth ; cell lines ; cell viability ; enzymes ; genes ; insulin ; therapeutics
    Language English
    Dates of publication 2020-0820
    Size p. 44-49.
    Publishing place Elsevier B.V.
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 843647-2
    ISSN 1873-4863 ; 0168-1656 ; 1389-0352
    ISSN (online) 1873-4863
    ISSN 0168-1656 ; 1389-0352
    DOI 10.1016/j.jbiotec.2020.04.016
    Database NAL-Catalogue (AGRICOLA)

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  8. Article ; Online: It's time to regulate: coping with product-induced nongenetic clonal instability in CHO cell lines via regulated protein expression.

    Misaghi, Shahram / Chang, Jennifer / Snedecor, Brad

    Biotechnology progress

    2014  Volume 30, Issue 6, Page(s) 1432–1440

    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 ... ...

    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.
    MeSH term(s) Animals ; Antibodies/analysis ; Antibodies/genetics ; Antibodies/metabolism ; CHO Cells ; Cell Culture Techniques/methods ; Cricetinae ; Cricetulus ; Gene Expression Regulation ; Genetic Vectors/genetics ; Recombinant Proteins/analysis ; Recombinant Proteins/genetics ; Recombinant Proteins/metabolism
    Chemical Substances Antibodies ; Recombinant Proteins
    Language English
    Publishing date 2014-11
    Publishing country United States
    Document type Journal Article
    ZDB-ID 165657-0
    ISSN 1520-6033 ; 8756-7938
    ISSN (online) 1520-6033
    ISSN 8756-7938
    DOI 10.1002/btpr.1970
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  9. Article ; Online: Development of a targeted integration Chinese hamster ovary host directly targeting either one or two vectors simultaneously to a single locus using the Cre/Lox recombinase-mediated cassette exchange system.

    Ng, Domingos / Zhou, Meixia / Zhan, Dejin / Yip, Shirley / Ko, Peggy / Yim, Mandy / Modrusan, Zora / Joly, John / Snedecor, Brad / Laird, Michael W / Shen, Amy

    Biotechnology progress

    2021  Volume 37, Issue 4, Page(s) e3140

    Abstract: Cell line development (CLD) by random integration (RI) can be labor intensive, inconsistent, and unpredictable due to uncontrolled gene integration after transfection. Unlike RI, targeted integration (TI) based CLD introduces the antibody-expressing ... ...

    Abstract Cell line development (CLD) by random integration (RI) can be labor intensive, inconsistent, and unpredictable due to uncontrolled gene integration after transfection. Unlike RI, targeted integration (TI) based CLD introduces the antibody-expressing cassette to a predetermined site by recombinase-mediated cassette exchange (RMCE). The key to success for the development of a TI host for therapeutic antibody production is to identify a transcriptionally active hotspot that enables highly efficient RMCE and antibody expression with good stability. In this study, a genome wide search for hotspots in the Chinese hamster ovary (CHO)-K1-M genome by either RI or PiggyBac (PB) transposase-based integration has been described. Two CHO-K1-M derived TI host cells were established with the Cre/Lox RMCE system and are described here. Both TI hosts contain a GFP-expressing landing pad flanked by two incompatible LoxP recombination sites (L3 and 2L). In addition, a third incompatible LoxP site (LoxFAS) is inserted in the GFP landing pad to enable an innovative two-plasmid based RMCE strategy, in which two separate vectors can be targeted to a single locus simultaneously. Cell lines generated by the TI system exhibit comparable or higher productivity, better stability and fewer sequence variant (SV) occurrences than the RI cell lines.
    MeSH term(s) Animals ; CHO Cells ; Cricetinae ; Cricetulus ; Integrases/genetics ; Recombinases/genetics ; Transgenes
    Chemical Substances Recombinases ; Cre recombinase (EC 2.7.7.-) ; Integrases (EC 2.7.7.-)
    Language English
    Publishing date 2021-04-09
    Publishing country United States
    Document type Journal Article
    ZDB-ID 165657-0
    ISSN 1520-6033 ; 8756-7938
    ISSN (online) 1520-6033
    ISSN 8756-7938
    DOI 10.1002/btpr.3140
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  10. Article ; Online: Utilizing a regulated targeted integration cell line development approach to systematically investigate what makes an antibody difficult to express.

    Tadauchi, Tomofumi / Lam, Cynthia / Liu, Laura / Zhou, Yizhou / Tang, Danming / Louie, Salina / Snedecor, Brad / Misaghi, Shahram

    Biotechnology progress

    2019  Volume 35, Issue 2, Page(s) e2772

    Abstract: Chinese hamster ovary (CHO) cells are conventionally used to generate therapeutic cell lines via random integration (RI), where desired transgenes are stably integrated into the genome. Targeted integration (TI) approaches, which involve integration of a ...

    Abstract Chinese hamster ovary (CHO) cells are conventionally used to generate therapeutic cell lines via random integration (RI), where desired transgenes are stably integrated into the genome. Targeted integration (TI) approaches, which involve integration of a transgene into a specific locus in the genome, are increasingly utilized for CHO cell line development (CLD) in recent years. None of these CLD approaches, however, are suitable for expression of toxic or difficult-to-express molecules, or for determining the underlying causes for poor expression of some molecules. Here we introduce a regulated target integration (RTI) system, where the desired transgene is integrated into a specific locus and transcribed under a regulated promoter. This system was used to determine the underlying causes of low protein expression for a difficult-to-express antibody (mAb-A). Interestingly, we observed that both antibody heavy chain (HC) and light chain (LC) subunits of mAb-A independently contributed to its low expression. Analysis of RTI cell lines also revealed that while mAb-A LC triggered accumulation of intracellular BiP, its HC displayed impaired degradation and clearance. RTI pools, generated by swapping the WT or point-mutant versions of difficult-to-express antibody HC and LC with that of an average antibody, were instrumental in understanding the contribution of HC and LC subunits to the overall antibody expression. The ability to selectively turn off the expression of a target transgene in an RTI system could help to directly link expression of a transgene to an observed adverse effect. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2772, 2019.
    MeSH term(s) Animals ; Antibodies, Monoclonal/genetics ; Antibodies, Monoclonal/metabolism ; CHO Cells ; Cells, Cultured ; Cricetulus
    Chemical Substances Antibodies, Monoclonal
    Language English
    Publishing date 2019-01-10
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 165657-0
    ISSN 1520-6033 ; 8756-7938
    ISSN (online) 1520-6033
    ISSN 8756-7938
    DOI 10.1002/btpr.2772
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