• Title, Summary, Keyword: Chinese hamster ovary (CHO) cell

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Correlation Between Enhancing Effect of Sodium Butyrate on Specific Productivity and mRNA Transcription Level in Recombinant Chinese Hamster Ovary Cells Producing Antibody

  • Jeon, Min-Kyoung;Lee, Gyun-Min
    • Journal of Microbiology and Biotechnology
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    • v.17 no.6
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    • pp.1036-1040
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    • 2007
  • Sodium butyrate (NaBu) has been used to enhance protein expression levels in mammalian cell culture. To determine the clonal variability of recombinant Chinese hamster ovary (rCHO) cells in response to NaBu addition regarding specific antibody productivity $(q_{Ab})$, three rCHO clones were subjected to different concentrations of NaBu. For all three clones, NaBu addition inhibited cell growth and decreased cell viability in a dose-dependent manner. On the other hand, the enhancing effect of NaBu on $q_{Ab}$ varied significantly among the clones. NaBu addition enhanced the antibody production of only one clone. RT-PCR analysis revealed that the changes in $q_{Ab}$ correlated linearly with those of the mRNA transcription level. Thus, it was concluded that the different enhancing effects of NaBu on protein expression in rCHO cell clones resulted from their different mRNA transcription levels.

High-Level Expression of Recombinant Human Interleukin-2 in Chinese Hamster Ovary Cells Using the Expression System Containing Transcription Terminator

  • Kim, Eun-Ju;Kim, Dong-Jun;Hwang, Hye-Yeon;Yoon, Jae-Seung;Yoon, Ye-Up;Baek, Kwang-Hee
    • Journal of Microbiology and Biotechnology
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    • v.14 no.4
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    • pp.810-815
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    • 2004
  • Many biological properties and the clinical potential of human interleukin-2 (hIL-2) draw much attention to its high-level expression in mammalian cells. Recombinant human IL-2 (rhIL-2) was expressed in Chinese hamster ovary (CHO) cells, using the recently developed expression system which confers position-independent expression. Stable CHO cell lines carrying several hundred amplified copies of the rhIL-2 gene were easily obtained and rhIL-2 was expressed at high levels after selection with increasing concentrations of methotrexate. Interestingly, the insertion of the transcription terminator of the human gastrin gene into the downstream region of the gene for rhIL-2 considerably increased rhIL-2 expression. Using the expression system with the transcription terminator, it was possible to get a CHO cell line expressing the rhIL-2 at a very high level, about $11.4\mug/10^6$ cell/day, which is about 6 times higher than that previously reported. The biological activity of the rhIL-2 protein purified from the cell line was also confirmed by the cell proliferation assay.

Expression of Recombinant Human Follicle-stimulating Hormone in the Chinese Hamster Ovary Cell

  • Park, Ji-Hyun;Kim, Nam-Hyung;Hosup Shim;Kim, Teoan
    • Proceedings of the Korean Society of Embryo Transfer Conference
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    • pp.100-100
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    • 2002
  • As an preliminary experiment for making transgenic animals producing human follicle stimulating hormone (hFSH), we tried to express recombinant hFSH gene in vitro. hFSH is a heterodimeric glycoprotein hormone produced in the anterior pituitary gland. The hormone is essential in the regulation of reproductive processes, such as follicular development and ovulation. Genes encoding the common gonadotrophin alpha subunit and FSH-specific beta subunit were inserted into retroviral vectors under the control of the rat beta actin promoter. Gene transfer to the Chinese hamster ovary (CHO) cells was done by infection of the retroviruses harvested from PT67 packaging cells transfected with recombinant retrovirus vector DNA. After selection with G4l8, PCR and RT-PCR analyses of the G4l8-resistant CHO cells showed successful transfer and expression of both ${\alpha}$ and ${\beta}$ fragments of the FSH gene.

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The efficient Erythropoietin expression system in Chinese Hamster Ovary cells by introduction of urea cycle enzymes

  • Lee, Yun-Jeong;Kim, Jung-Kwon;Kim, Hyung-Jin;Kim, Na-Young;Kim, Jung-Hoe;Kim, Hong-Jin
    • Proceedings of the PSK Conference
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    • pp.231.2-231
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    • 2003
  • The efficient EPO (Erythropoietin) expression system in Chinese Hamster Ovary (CHO) cells was devised through the removal of ammonium ion accumulated in the media by introducing urea cycle enzymes. Previously, we developed C05 cell by transfecting the carbamoly phosphate synthase (CPS) and ornithine transcarbamoylase (OTC) into the EPO expressing CHO cell, IBE. (omitted)

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Effects of Silkworm Gland Hydrolysate on Albumin-erythropoietin Production in Transgenic Chinese Hamster Ovary Cells (형질전환 Chinese Hamster Ovary 세포에서 Albumin-erythropoietin의 생산시 Silkworm Gland Hydrolysate의 효과)

  • Choi, Min-Ho;Cha, Hyun-Myoung;Kim, Sun-Mi;Choi, Yong-Soo;Kim, Dong-Il
    • KSBB Journal
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    • v.28 no.2
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    • pp.86-91
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    • 2013
  • To date, various strategies have been studied to increase specific productivity in Chinese hamster ovary (CHO) cell cultures. Also, albumin-fusion platform is being applied to other important bioactive peptides with short half-lives. Here, we investigated the effects of silkworm gland hydrolysate (SGH) on the production of albumin-erythropoietin (Alb-EPO) in transgenic CHO cells. The viable cell density of CHO cells was increased by 13% in the medium containing 1 mg/mL SGH higher than in the control medium without SGH. In addition, the production of Alb-EPO was also 1.26- fold enhanced by reducing the early apoptosis of CHO cells. In conclusion, SGH could be used as a useful supplement for the enhancement of recombinant protein production.

High-Level Expression of Recombinant Human Bone Morphogenetic Protein-4 in Chinese Hamster Ovary Cells

  • PARK JUNHO;YU SUNGRYUL;YOON JAESEUNG;BAEK KWANGHEE
    • Journal of Microbiology and Biotechnology
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    • v.15 no.6
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    • pp.1397-1401
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    • 2005
  • Bone morphogenetic protein-4 (BMP-4) is a signaling homodimeric molecule that acts as a morphogen to influence cell fate in a concentration-dependent manner. The limited supply of a pure preparation of BMP-4, due to very low level of their expression in vivo, makes it difficult not only to study the biological activities of BMPs, but also to use them as a clinical tool. For a large-scale production of BMP-4, human BMP-4 cDNA was expressed in Chinese hamster ovary (CHO) cells by a recently development vector system, which confers position-independent stable expression of the foreign genes. The CHO cell line expressing recombinant human BMP-4 (rhBMP-4) at the level of $7\;{\mu}g/ml$ could be obtained after stepwise selection with methotrexate. This level of expression is about 70 times higher than those previously reported. The partially processed form of BMP-4 as well as mature form could be detected, when the aliquots of culture media were analyzed by Western blot. The glycosylation pattern and biological activity of the rhBMP-4 were determined by glycosidase treatment and the induction rate of alkaline phosphatase in mouse osteoblastic cells.

Zinc and Selenium Requirements for Glutathione Peroxidase Activity and Cell Survival in Chinese Hamster Ovary Cells Overexpressing Metallothionein

  • Kwun, In-Sook;John R. Arthur;John H. Beattie
    • Preventive Nutrition and Food Science
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    • v.8 no.1
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    • pp.36-39
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    • 2003
  • Many defined cell culture media were formulated over 3() years ago and may be deficient in certain micronutrients whose essentiality has only subsequently been recognised. The objective of this study was to evaluate whether alpha-minimal essential medium (MEM) supplemented with 10% foetal bovine serum contained sufficient selenium for optimal activity of the selenium containing enzymes cytosolic glutathione peroxidase (cGPx) and phospholipid hydroperoxide glutathione peroxidase (PHGPx) in cultured Chinese hamster ovary (CHO) cells. Additionally, the effect of zinc deficiency and metallothionein (MT) overexpression on cGPx and PHGPx activity was studied. The addition of 100 nM of selenous acid to the culture medium increased cGPx expression by 10-fold and PHGPx by about 2-fold in both wild-type CHO-K1 cells and CHO-K1 cells overexpressing mouse MT-1. Zinc deficiency had no significant effect on enzyme activity, but cells overexpressing mouse MT-1 had higher levels of cGPx activity. Zinc deficiency decreased cell survival but overexpression of MT-1 was partially protective, probably because its presence in quantity favoured the uptake, sequestration and cellular retention of any remaining zinc. This study demonstrates that selenium in complete alpha-MEM is insufficient for optimal cGPx and PHGPx activity and may compromise the cellular response to oxidative stress.

Changes in Cell Cycle-related Genes Expression of Chineses Hamster Ovary Cells cultured using Serum-free Media

  • Seo, Sung-Keum;Park, Hong-Woo;Choe, Tae-Boo
    • 한국생물공학회:학술대회논문집
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    • pp.153-158
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    • 2003
  • The genome-wide program of gene expression during the cell division cycle response to serum free media in chinese hamster ovary(CHO) cells was characterized using cDNA microarrays. Many transcripts of genes showed variation during the cell cycle. Characterization is critical step toward understanding the basic cell cycle processes and serum-free media role in CHO cells

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Screening of High-Productivity Cell Lines and Investigation of Their Physiology in Chinese Hamster Ovary (CHO) Cell Cultures for Transforming Growth $Factor-{\beta}1$ Production

  • Chun, Gin-Taek;Lee, Joo-Buom;Nam, Sang-Uk;Lee, Se-Won;Jeong, Yeon-Ho;Choi, Eui-Yul;Kim, Ik-Hwan;Jeong, Yong-Seob;Kim, Pyeong-Hyeun
    • Journal of Microbiology and Biotechnology
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    • v.12 no.1
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    • pp.121-129
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    • 2002
  • Using recombinant Chinese hamster ovary (CHO) cells, strategies for developing high producers for the recombinant human Transforming Growth $Factor-{\beta}1$ ($TGF-{\beta}1$) protein are proposed and their physiological characteristics in cell cultures were investigated. $TGF-{\beta}1$ is a pleiotrophic polypeptide involved in various biological activities, including cell growth, differentiation, and deposition of extracellular matrix proteins. The CHO cells included human $TGF-{\beta}1$ cDNA in conjunction with a dihydrofolate reductase (DHFR) gene, which was cotransfected into the cells to amplify the transfected $TGF-{\beta}1$ cDNA. As a first-round screening of the transfected cells, a relatively high $TGF-{\beta}1$-producing cell line was selected, and then, it acquired a resistance to increasing concentrations of methotrexate (MTX) up to $60{\mu}M$,resulting in a significant improvement in its $TGF-{\beta}1$ biosynthetic ability. After applying a monoclonal selection strategy to the MTX-resistant cells, more productive cells were screened, including the APP-3, App-5, and App-8 cell lines. These high producers were compared with two other cell lines (AP-l cell line without amplification of transfected $TGF-{\beta}1$ cDNA and nontransfectant of $TGF-{\beta}1$ cDNA) in terms of cell growth, $TGF-{\beta}1$ productivity, sugar uptake, and byproduct formation, in the presence or absence of MTX in the culture medium. Consequently, both monoclonal selection as well as an investigation of the physiological characteristics were found to be needed for the efficient screening of higher $TGF-{\beta}1$ producers, even after the transfection and amplification of the transfected gene.

Change of Insulin-like Growth Factor Gene Expression in Chinese Hamster Ovary Cells Cultured in Serum-free Media

  • Park, Hong-Woo;An, Sung-Kwan;Choe, Tae-Boo
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.11 no.4
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    • pp.319-324
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    • 2006
  • Although the sera used in animal cell culture media provide the macromolecules, nutrients, hormones, and growth factors necessary to support cell growth, it could also be an obstacle to the production of recombinant proteins in animal cell culture systems used in many sectors of the biotechnology industry. For this reason, many research groups, including our laboratory, have been trying to develop serum-free media (SFM) or serum-supplemented media (SSM) for special or multi-purpose cell lines. The Chinese hamster ovary (CHO) cell, for example, is frequently used to produce proteins and is especially valuable in the large-scale production of pharmaceutically important proteins, yet information about its genome is lacking. Also, SFMs have only been evaluated by comparing growth patterns for cells grown in SFMs with those grown in SSM or by measuring the titer of the target protein obtained from cells grown in each type of medium. These are not reliable methods of obtaining the type of information needed to determine whether an SFM should be replaced with an SSM. We carried out a cDNA microarray analysis to evaluate MED-3, an SFM developed in our laboratory, as a CHO culture medium When CHO cells were cultured in MED-3 instead of an SSM, several genes associated with cell growth were down-regulated, although this change diminished over time. We found that the insulin-like growth factor (IGF) gene was representative of the proteins that were down-regulated in cells cultured in MED-3. When several key supplements - including insulin, transferrin, ethanolamine, and selenium - were removed from MED-3, the IGF expression was consistently down- regulated and cell growth decreased proportionately. Based on these results, we concluded that when an SFM is used as a culture medium, it is important to supplement it with substances that can help the cells maintain a high level of IGF expression. The data presented in this study, therefore, might provide useful information for the design and development of SFM or SSM, as well as for the design of genome-based studies of CHO cells to determine how they can be used optimally for protein production in pharmaceutical and biomedical research.