1
|
Han MM, Wang HT, Zhang HJ, Lu JT, Guo JL, Qiu LL, Zhang X, Wang XY, Wang TY, Jia YL. A novel dual-epigenetic inhibitor enhances recombinant monoclonal antibody expression in CHO cells. Appl Microbiol Biotechnol 2024; 108:467. [PMID: 39292268 PMCID: PMC11411004 DOI: 10.1007/s00253-024-13302-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 08/20/2024] [Accepted: 09/02/2024] [Indexed: 09/19/2024]
Abstract
Epigenetic regulation plays a central role in the regulation of a number of cellular processes such as proliferation, differentiation, cell cycle, and apoptosis. In particular, small molecule epigenetic modulators are key elements that can effectively influence gene expression by precisely regulating the epigenetic state of cells. To identify useful small-molecule regulators that enhance the expression of recombinant proteins in Chinese hamster ovary (CHO) cells, we examined a novel dual-HDAC/LSD1 inhibitor I-4 as a supplement for recombinant CHO cells. Treatment with 2 μM I-4 was most effective in increasing monoclonal antibody production. Despite cell cycle arrest at the G1/G0 phase, which inhibits cell growth, the addition of the inhibitor at 2 µM to monoclonal antibody-expressing CHO cell cultures resulted in a 1.94-fold increase in the maximal monoclonal antibody titer and a 2.43-fold increase in specific monoclonal antibody production. In addition, I-4 significantly increased the messenger RNA levels of the monoclonal antibody and histone H3 acetylation and methylation levels. We also investigated the effect on HDAC-related isoforms and found that interference with the HDAC5 gene increased the monoclonal antibody titer by 1.64-fold. The results of this work provide an effective method of using epigenetic regulatory strategies to enhance the expression of recombinant proteins in CHO cells. KEY POINTS: • HDAC/LSD1 dual-target small molecule inhibitor can increase the expression level of recombinant monoclonal antibodies in CHO cells. • By affecting the acetylation and methylation levels of histones in CHO cells and downregulating HDAC5, the production of recombinant monoclonal antibodies increased. • It provides an effective pathway for applying epigenetic regulation strategies to enhance the expression of recombinant proteins.
Collapse
Affiliation(s)
- Ming-Ming Han
- School of Pharmacy, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- Henan Engineering Research Center for Biopharmaceutical Innovation, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Hai-Tong Wang
- School of Pharmacy, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- Henan Engineering Research Center for Biopharmaceutical Innovation, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Hui-Jie Zhang
- School of Pharmacy, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- Henan Engineering Research Center for Biopharmaceutical Innovation, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Jiang-Tao Lu
- School of Pharmacy, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- Henan Engineering Research Center for Biopharmaceutical Innovation, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Jia-Liang Guo
- Junji College, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Le-Le Qiu
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Xi Zhang
- School of Pharmacy, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- Henan Engineering Research Center for Biopharmaceutical Innovation, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Xiao-Yin Wang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- Henan Engineering Research Center for Biopharmaceutical Innovation, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Tian-Yun Wang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China.
- Henan Engineering Research Center for Biopharmaceutical Innovation, Xinxiang Medical University, Xinxiang, 453003, Henan, China.
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, 453003, Henan, China.
| | - Yan-Long Jia
- School of Pharmacy, Xinxiang Medical University, Xinxiang, 453003, Henan, China.
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China.
- Henan Engineering Research Center for Biopharmaceutical Innovation, Xinxiang Medical University, Xinxiang, 453003, Henan, China.
| |
Collapse
|
2
|
Zhang J, Wang L, Zhang X, Sun Q, Zhang J. Matrix attachment regions enhance transgene expression by manipulating position-dependent effects in stably transfected CHO-K1 cells. Biochem Cell Biol 2024. [PMID: 39029107 DOI: 10.1139/bcb-2023-0337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2024] Open
Abstract
We previously found that the position of matrix attachment regions (MARs) within the vector significantly affects its ability to enhance transgenic expression in the recombinant protein production. This study aims to systematically investigate the position-dependent impacts of MAR on transgene expression. We observed a significant increase in enhanced green fluorescent protein (eGFP) expression levels in stably transfected CHO-K1 cells with either MAR 1-68 or MAR X-29 when MARs located upstream of the promoter. This increase was especially evident with MAR flanked the expression cassette. Concurrently, a substantial increase was observed in the percentage of eGFP-expressing cells, with 97.8% and 96.0% in MAR-containing constructs versus 73.7% in MAR-absent constructs. Further analysis of erythropoietin (EPO) expression revealed that constructs with flanking MARs induced the highest EPO productivity. Bioinformatics analysis revealed that certain specific transcription factors are important in modulating the transcription process. In conclusion, vectors harboring both MARs around the expression cassette constitute an optimal construct for enhanced recombinant protein production in CHO-K1 cells. This insight underscores the importance of strategic MAR incorporation in vector design for optimized recombinant protein expression.
Collapse
Affiliation(s)
- Jihong Zhang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang 453003, China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang 453003, China
| | - Lin Wang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang 453003, China
| | - Xi Zhang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang 453003, China
| | - Qiuli Sun
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang 453003, China
| | - Junhe Zhang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang 453003, China
- Institutes of Health Central Plains, Xinxiang Medical University, Xinxiang 453003, China
| |
Collapse
|
3
|
Liu HN, Wang XY, Zou Y, Wu WB, Lin Y, Ji BY, Wang TY. Synthetic enhancers including TFREs improve transgene expression in CHO cells. Heliyon 2024; 10:e26901. [PMID: 38468921 PMCID: PMC10926067 DOI: 10.1016/j.heliyon.2024.e26901] [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: 12/27/2023] [Revised: 02/12/2024] [Accepted: 02/21/2024] [Indexed: 03/13/2024] Open
Abstract
The human cytomegalovirus major immediate early gene (CMV) promoter is currently the most preferred promoter for recombinant therapeutic proteins (RTPs) production in CHO cells. To enhance the production of RTPs, five synthetic enhancers including multiple transcription factor regulatory elements (TFREs) were evaluated to enhance recombinant protein level in transient and stably transfected CHO cells. Compared with the control, four elements can enhance the report genes expression under both two transfected states. Further, the function of these four enhancers on human serum albumin (HSA) were investigated. We found that the transient expression can increase by up to 1.5 times, and the stably expression can maximum increase by up to 2.14 times. The enhancement of transgene expression was caused by the boost of their corresponding mRNA levels. Transcriptomics analysis was performed and found that transcriptional activation and cell cycle regulation genes were involved. In conclusion, optimization of enhancers in the CMV promoter could increase the production yield of transgene in transfected CHO cells, which has significance for developing high-yield CHO cell expression system.
Collapse
Affiliation(s)
- Hui-Ning Liu
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang 453003, China
- SanQuan College of Xinxiang Medical University, Xinxiang 453003, China
| | - Xiao-Yin Wang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang 453003, China
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Xinxiang Medical University, Xinxiang 453003, China
| | - Ying Zou
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang 453003, China
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Xinxiang Medical University, Xinxiang 453003, China
| | - Wen-Bao Wu
- Shanghai Immunocan Biotech Co., LTD, Shanghai 200000, China
| | - Yan Lin
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang 453003, China
| | - Bo-Yu Ji
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang 453003, China
| | - Tian-Yun Wang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang 453003, China
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Xinxiang Medical University, Xinxiang 453003, China
| |
Collapse
|
4
|
Wang XY, Zhang WL, Zhang X, Fu YS, Wang HM, Sun QL, Li Q, Jia YL, Zhang JH, Wang TY. Combination of MAR and intron increase transgene expression of episomal vectors in CHO cells. Biotechnol J 2023; 18:e2200643. [PMID: 37551822 DOI: 10.1002/biot.202200643] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 07/22/2023] [Accepted: 08/03/2023] [Indexed: 08/09/2023]
Abstract
Previous work has shown that the EF-1α promoter of episomal vectors maintains high-level transgene expression in stably transfected Chinese hamster ovary (CHO) cells. However, the transgene expression levels need to be further increased. Here, we first incorporated matrix attachment regions (MARs), ubiquitous chromatin opening element (UCOE), stabilizing anti repressor elements 40 (STAR 40) elements into episomal vector at different sites and orientations, and systemically assessed their effects on transgene expression in transfected CHO-K1 cells. Results showed that enhanced green fluorescent protein (eGFP) expression levels increased remarkably when MAR X-29 was inserted upstream of the promoter, followed by the insertion of MAR1 downstream of the poly A, and the orientation had no significant effect. Moreover, MAR X-29 combined with human cytomegalovirus intron (hCMVI) yielded the highest transgene expression levels (4.52-fold). Transgene expression levels were not exclusively dependent on transgene copy numbers and were not related to the mRNA expression level. In addition, vector with MAR X-29+hCMVI can induce herpes simplex virus thymidine kinase (HSV-TK) protein expression, and the HSV-TK protein showed a cell-killing effect and an obvious bystander effect on HCT116 cells. In conclusion, the combination of MAR X-29 and hCMV intron can achieve high efficiency transgene expression mediated by episomal vectors in CHO-K1 cells.
Collapse
Affiliation(s)
- Xiao-Yin Wang
- School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| | - Wei-Li Zhang
- School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
- Center for Medical Genetics, Nanyang Second General Hospital, Nanyang, China
| | - Xi Zhang
- College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Yu-Shun Fu
- School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Hao-Min Wang
- School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Qiu-Li Sun
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| | - Qin Li
- School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Yan-Long Jia
- College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Jun-He Zhang
- Institutes of Health Central Plains, Xinxiang Medical University, Xinxiang, China
| | - Tian-Yun Wang
- School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| |
Collapse
|
5
|
Zhang Q, Mi C, Wang T. Effects and mechanism of small molecule additives on recombinant protein in CHO cells. Appl Microbiol Biotechnol 2023; 107:2771-2781. [PMID: 36971794 DOI: 10.1007/s00253-023-12486-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 03/15/2023] [Accepted: 03/16/2023] [Indexed: 03/29/2023]
Abstract
Chinese hamster ovary (CHO) cells can produce proteins with complex structures and post-translational modifications which are similar to human-derived cells, and they have been the ideal host cells for the production of recombinant therapy proteins (RTPs). Nearly 70% of approved RTPs are produced by CHO cells. In recent years, a series of measures have been developed to increase the expression of RTPs to achieve the lower production cost during the process of large-scale industrial production of recombinant protein in CHO cells. Among of them, the addition of small molecule additives in the culture medium can improve the expression and production efficiency of recombinant proteins, and has become an effective and simple method. In this paper, the characteristics of CHO cells, the effect and mechanism of small molecule additives are reviewed. KEY POINTS: • Small molecular additives on the expression of RTPs in CHO cells are reviewed • Small molecular additives improve the yield of RTPs • Small molecular additives provide methods for the optimization of serum-free medium.
Collapse
Affiliation(s)
- Qiuli Zhang
- School of Pharmacy, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Chunliu Mi
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Tianyun Wang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China.
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, 453003, Henan, China.
| |
Collapse
|
6
|
Li Q, Yan RF, Yang YX, Mi CL, Jia YL, Wang TY. Stabilizing and Anti-Repressor Elements Effectively Increases Transgene Expression in Transfected CHO Cells. Front Bioeng Biotechnol 2022; 10:840600. [PMID: 35721852 PMCID: PMC9199445 DOI: 10.3389/fbioe.2022.840600] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 04/21/2022] [Indexed: 11/13/2022] Open
Abstract
Chinese hamster ovary (CHO) cells are currently the most widely used host cells for recombinant therapeutic protein (RTP) production. Currently, the RTP yields need to increase further to meet the market needs and reduce costs. In this study, three stabilizing and anti-repressor (SAR) elements from the human genome were selected, including human SAR7, SAR40, and SAR44 elements. SAR elements were cloned upstream of the promoter in the eukaryotic vector, followed by transfection into CHO cells, and were screened under G418 pressure. Flow cytometry was used to detect enhanced green fluorescent protein (eGFP) expression levels. The gene copy numbers and mRNA expression levels were determined through quantitative real-time PCR. Furthermore, the effect of the stronger SAR elements on adalimumab was investigated. The results showed that transgene expression levels in the SAR-containing vectors were higher than that of the control vector, and SAR7 and SAR40 significantly increased and maintained the long-term expression of the transgene in CHO cells. In addition, the transgene expression level increase was related with gene copy numbers and mRNA expression levels. Collectively, SAR elements can enhance the transgene expression and maintain the long-term expression of a transgene in transfected CHO cells, which may be used to increase recombinant protein production in CHO cells.
Collapse
Affiliation(s)
- Qin Li
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, China.,International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| | - Rui-Fang Yan
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, China
| | - Yong-Xiao Yang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| | - Chun-Liu Mi
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, China.,International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| | - Yan-Long Jia
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| | - Tian-Yun Wang
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, China.,International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| |
Collapse
|
7
|
Dou Y, Lin Y, Wang TY, Wang XY, Jia YL, Zhao CP. The CAG promoter maintains high-level transgene expression in HEK293 cells. FEBS Open Bio 2020; 11:95-104. [PMID: 33155423 PMCID: PMC7780116 DOI: 10.1002/2211-5463.13029] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/03/2020] [Accepted: 11/04/2020] [Indexed: 12/11/2022] Open
Abstract
The vast majority of therapeutic recombinant proteins are produced in mammalian cell lines. However, proteins generated in nonhuman cell lines, such as Chinese hamster ovary (CHO) cells, are decorated with human‐like glycan structures that differ from those of human cells, and these may induce immunogenic responses in human cells. Human embryonic kidney cells (HEK293F) are also extensively used as hosts for the expression of recombinant therapeutic proteins, but their utility is limited by the low expression of transgenes in these cells. Here, we investigated recombinant protein expression from eight frequently used promoters in transfected HEK293F cells. The expression levels and stability of the transgenes were evaluated by flow cytometry and qRT‐PCR. The most efficient expression (in terms of both mRNA and protein yields) was achieved using a cytomegalovirus (CMV) major immediate‐early enhancer combined with the chicken beta‐actin promoter (CAG) promoter, as compared to all other tested promoters under both transient and stable transfection conditions. In addition, application of mild hypothermia (i.e., 33 °C) after transfection improved the positive effect of the CMV enhancer fused to the chicken beta‐actin promoter (CAG promoter) on enhanced green fluorescent protein (eGFP) expression. Although the temperature sensitivity of the CMV promoter is greater than that of CAG promoter, recombinant protein levels were still highest when expression was driven by the CAG promoter. When eGFP was replaced with hepatitis B surface antigen, the CAG promoter still showed the highest transgene expression. In conclusion, our data show that the CAG promoter is a strong promoter for recombinant protein expression in HEK293F cells.
Collapse
Affiliation(s)
- Yuanyuan Dou
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, China.,Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, Xinxiang, China
| | - Yan Lin
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, China
| | - Xiao-Yin Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, China
| | - Yan-Long Jia
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, Xinxiang, China
| | - Chun-Peng Zhao
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, China
| |
Collapse
|
8
|
Zhang J, Zhang J, Cheng S, Yang W, Li S. Enhanced transgene expression using two β-globin MARs flanking expression cassettes in stably transfected CHO-K1 cells. 3 Biotech 2019; 9:435. [PMID: 31696040 DOI: 10.1007/s13205-019-1971-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/23/2019] [Indexed: 02/02/2023] Open
Abstract
In this study, we systemically investigated the positions and orientations of matrix attachment regions (MARs) in expression vectors to fully explore the mechanism for improving transgene expression. We constructed 14 vectors that incorporated human β-globin MARs into pIRES-eGFP backbone vectors. The MARs flanked the eGFP expression cassette or promoter in a forward/reverse orientation. After stable transfection into CHO-K1 cells with these vectors, eGFP expression levels were increased significantly relative to that of the control vector (MAR-devoid) when two MARs flanking the expression cassette were incorporated, followed by those at the 5' site (upstream of the promoter). Simultaneously, the percentage of the eGFP-expressing cells was elevated to some extent. The vector with both MARs in forward orientation flanking the expression cassette yielded the highest transgene expression levels (2.5-fold). The orientation (forward or reverse) of the MARs did not present a significant difference when added in the same site. In addition, transgene expression levels were not exclusively dependent on transgene copy numbers. Bioinformatic analysis indicated that some specific transcription factors may contribute to the transcriptional process. In conclusion, two MARs in a forward orientation and flanking the expression cassette comprised the optimal construct for improving the stable transgene expression in the CHO-K1 cells. The effects may be related to specific transcription factors, such as PRDM1 and REL.
Collapse
Affiliation(s)
- Jihong Zhang
- 1School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang, 453003 China
| | - Junhe Zhang
- 1School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang, 453003 China
| | - Shan Cheng
- 1School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan China
| | - Wenwen Yang
- 1School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang, 453003 China
| | - Shijiang Li
- 3The First Affiliated Hospital of Xinxiang Medical University, Weihui, 453100 China
| |
Collapse
|
9
|
Jia YL, Guo X, Ni TJ, Lu JT, Wang XY, Wang TY. Novel short synthetic matrix attachment region for enhancing transgenic expression in recombinant Chinese hamster ovary cells. J Cell Biochem 2019; 120:18478-18486. [PMID: 31168866 DOI: 10.1002/jcb.29165] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 05/18/2019] [Accepted: 05/23/2019] [Indexed: 01/17/2023]
Abstract
Matrix attachment regions (MARs) are DNA fragments with specific motifs that enhance transgenic expression; however, the characteristics and functions of these elements remain unclear. In this study, we designed and synthesized three short chimeric MARs, namely, SM4, SM5, and SM6, with different numbers and orders of motifs on the basis of the features and motifs of previously reported MARs, namely, SM1, SM2, and SM3, respectively. Expression vectors with six synthetic MARs flanking the down or upstream of the expression cassette for enhanced green fluorescence protein (EGFP) were constructed and introduced into Chinese hamster ovary (CHO) cells. Results indicated that the EGFP expression of the CHO cells with transfection bySM4, SM5, or SM6-containing vectors was higher than that of those containing SM1, SM2, or SM3 regardless of the MAR insertion position. The improving effect of SM5 was particularly pronounced. Transgenic expression was further enhanced with the increasing SM5 copy number. Bioinformatics analysis indicated that several arrangements of the DNA-binding motifs for CEBP, FAST, Hox, glutathione, and NMP4 may help increase transgenic expression levels and the average population of highly expressed cells. Our findings on novel synthetic MARs will help establish stable expression systems in mammalian cells.
Collapse
Affiliation(s)
- Yan-Long Jia
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Xiao Guo
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Tian-Jun Ni
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, Henan, China
| | - Jiang-Tao Lu
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Xiao-Yin Wang
- International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China.,School of Basic Medicine, Xinxiang Medical University, Xinxiang, Henan, China
| | - Tian-Yun Wang
- International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China.,School of Basic Medicine, Xinxiang Medical University, Xinxiang, Henan, China
| |
Collapse
|
10
|
Gao JH, Wang TY, Zhang MY, Shi F, Gu SZ. Identification of consensus sequence from matrix attachment regions and functional analysis of its activity in stably transfected Chinese hamster ovary cells. J Cell Biochem 2019; 120:13985-13993. [PMID: 30957285 DOI: 10.1002/jcb.28673] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 12/30/2018] [Accepted: 01/09/2019] [Indexed: 01/01/2023]
Abstract
Matrix attachment regions (MARs) can enhance transgene expression levels and maintain stability. However, the consensus sequence from MARs and its functional analysis remains to be examined. Here, we assessed a possible consensus sequence from MARs and assessed its activity in stably transfected Chinese hamster ovary (CHO) cells. First, we analyzed the effects of 10 MARs on transfected CHO cells and then analyzed the consensus motifs from these MARs using a bioinformatics method. The consensus sequence was synthesized and cloned upstream or downstream of the eukaryotic vector. The constructs were transfected into CHO cells and the expression levels and stability of enhanced green fluorescent protein were detected by flow cytometry. The results indicated that eight of the ten MARs increased transgene expression in transfected CHO cells. Three consensus motifs were found after bioinformatics analyses. The consensus sequence tandemly enhanced transgene expression when it was inserted into the eukaryotic expression vector; the effect of the addition upstream was stronger than that downstream. Thus, we found a MAR consensus sequence that may regulate the MAR-mediated increase in transgene expression.
Collapse
Affiliation(s)
- Jian-Hui Gao
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Mao-Ying Zhang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Fang Shi
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Shan-Zhi Gu
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
| |
Collapse
|
11
|
Yang B, Zhou J, Zhao H, Wang A, Lei Y, Xie Q, Xiong S. Study of the mechanism for increased protein expression via transcription potency reduction of the selection marker. Bioprocess Biosyst Eng 2019; 42:799-806. [PMID: 30730009 DOI: 10.1007/s00449-019-02083-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 01/24/2019] [Indexed: 01/02/2023]
Abstract
Stable transfection of mammalian cells using various expression cassettes for exogenous gene expression has been well established. The impact of critical factors in these cassettes, such as promoter and enhancer elements, on recombinant protein production in mammalian cells has been studied extensively to optimize the expression efficiency. However, few studies on the correlation between the strength of selection marker and the expression of gene of interest (GOI) have been reported. Here we investigated the correlation between the strength of a widely used selection marker, glutamine synthetase (GS) gene, and gene of interest in which the expression of GOI is driven by mouse cytomegalovirus (mCMV) major immediate early (MIE) promoter whereas the expression of GS is controlled by SV40E (Simian vacuolating virus 40E) promoter. We used a green fluorescent protein and the adalimumab antibody (heavy and light chain) as two distinct examples for the gene of interest. We then decreased the expression of GS gene by engineering a specific region of its SV40E promoter in these expression cassettes. By comparing the expression of GS and GOI at transcription and translation level before and after the SV40E promoter was weakened, we found that lower GS expression due to weaker SV40E transcription correlated well with the higher expression of recombinant proteins, mainly by increasing the copy number of GS and GOI integration into host cell genome.
Collapse
Affiliation(s)
- Bin Yang
- Department of Cell Biol, Institute of Biomedicine & National Engineering Research Center of Genetic Medicine, College of Life Science and Technology, Jinan University, 730 Building of Biology, 601 W Huangpu Ave, Guangzhou, 510630, Guangdong, People's Republic of China
| | - Jiatao Zhou
- Sunshine Lake Pharma Co., Ltd., Zhen An Road, Dongguan, 523867, People's Republic of China
| | - Hui Zhao
- Department of Cell Biol, Institute of Biomedicine & National Engineering Research Center of Genetic Medicine, College of Life Science and Technology, Jinan University, 730 Building of Biology, 601 W Huangpu Ave, Guangzhou, 510630, Guangdong, People's Republic of China
| | - Anling Wang
- Department of Cell Biol, Institute of Biomedicine & National Engineering Research Center of Genetic Medicine, College of Life Science and Technology, Jinan University, 730 Building of Biology, 601 W Huangpu Ave, Guangzhou, 510630, Guangdong, People's Republic of China
| | - Yuanjun Lei
- Department of Cell Biol, Institute of Biomedicine & National Engineering Research Center of Genetic Medicine, College of Life Science and Technology, Jinan University, 730 Building of Biology, 601 W Huangpu Ave, Guangzhou, 510630, Guangdong, People's Republic of China
| | - Qiuling Xie
- Department of Cell Biol, Institute of Biomedicine & National Engineering Research Center of Genetic Medicine, College of Life Science and Technology, Jinan University, 730 Building of Biology, 601 W Huangpu Ave, Guangzhou, 510630, Guangdong, People's Republic of China
| | - Sheng Xiong
- Department of Cell Biol, Institute of Biomedicine & National Engineering Research Center of Genetic Medicine, College of Life Science and Technology, Jinan University, 730 Building of Biology, 601 W Huangpu Ave, Guangzhou, 510630, Guangdong, People's Republic of China.
| |
Collapse
|
12
|
Li Q, Zhao CP, Lin Y, Song C, Wang F, Wang TY. Two human MARs effectively increase transgene expression in transfected CHO cells. J Cell Mol Med 2018; 23:1613-1616. [PMID: 30450759 PMCID: PMC6349195 DOI: 10.1111/jcmm.14018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 12/12/2022] Open
Abstract
Matrix attachment regions (MARs) can enhance the expression level of transgene in Chinese hamster ovaries (CHO) cell expression system. However, improvements in function and analyses of the mechanism remains unclear. In this study, we screened two new and more functional MAR elements from the human genome DNA. The human MAR-3 and MAR-7 element were cloned and inserted downstream of the polyA site in a eukaryotic vector. The constructs were transfected into CHO cells, and screened under G418 to produce the stably transfected cell pools. The expression levels and stability of enhanced green fluorescent protein (eGFP) were detected by flow cytometry. The transgene copy number and transgene expression at mRNA level were detected by quantitative real-time PCR. The results showed that the expression level of eGFP of cells transfected with MAR-containing vectors were all higher than those of the vectors without MARs under transient and stably transfection. The enhancing effect of MAR-7 was higher than that of MAR-3. Additionally, we found that MAR significantly increased eGFP copy numbers and eGFP gene mRNA expression level as compared with the vector without. In conclusion, MAR-3 and MAR-7 gene can promote the expression of transgene in transfected CHO cells, and its effect may be related to the increase of the number of copies.
Collapse
Affiliation(s)
- Qin Li
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Chun-Peng Zhao
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Yan Lin
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Chao Song
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Fang Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| |
Collapse
|
13
|
Human rhinovirus internal ribosome entry site element enhances transgene expression in transfected CHO-S cells. Sci Rep 2018; 8:6661. [PMID: 29703950 PMCID: PMC5923211 DOI: 10.1038/s41598-018-25049-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/13/2018] [Indexed: 01/27/2023] Open
Abstract
Chinese hamster ovary (CHO) cells are mainly used for recombinant protein production. However, the unstable transgene expression and lower transgene copy numbers are the major issues need to be resolved. Here, eleven internal ribosome entry site (IRES) elements from viral and cellular IRES were evaluated for foreign gene expression in CHO-S cells. We constructed eleven fusing plasmids containing different IRES sequences downstream of the enhanced green fluorescent protein (EGFP) gene. EGFP expression was detected by flow cytometry and the transgene copy number was evaluated by quantitative PCR. The erythropoietin (EPO) protein was also used to assess the stronger IRES. The results showed that IRES from human rhinovirus (HRV) exhibited the highest EGFP expression level under transient and stable transfections. The EGFP expression level of vector with IRES from HRV was related to the gene copy number in stably transfected CHO-S cells. Moreover, IRES from HRV induced higher expression level of EPO compared with one mutant IRES from EMCV in transfected cells. In conclusion, IRES from HRV can function as a strong IRES element for stable expression in CHO-S cells, which could potentially guide more effective foreign gene expression in CHO-S cells.
Collapse
|