• Title/Summary/Keyword: stable transfection

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Antibody productivity of HBsAg containing both preS2 and S regions expressed in Chinese hamster ovary cells (Chinese hamster ovary세포에서 발현된 pres2 및 S부위 함유 HBsAg의 항체유발능)

  • 정성균;박정민;이상봉;박동우;김동연;김기호;김홍진
    • YAKHAK HOEJI
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    • v.45 no.6
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    • pp.708-714
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    • 2001
  • Many studies have provided evidences that hepatitis B surface antigen (HBsAg) including preS region could be an ideal candidate for a new hepatitis B virus (HBV) vaccine with higher efficacy. We established CHO cell lines, IY-CHO-2 and IY-CHO-11 expressing high levels of HBsAg containing preS2 and S protein by stable transfection method. These cell lines expressed the correct size (about 1 kb in length) of HBsAg mRNA as expected. The purified protein from the culture supernatants of the clones showed the same sizes as those expressed in native hepatitis B virus (24 kDa, 27 kDa, 34 kDa and 36 kDa). Antibody productivity of CHO-derived HBsAg protein at lower dose challenge was higher than the protein containing S region alone expressed in yeast system. These results indicate that CHO-derived HBsAg protein containing preS2 and S region can be effectively used for a better immune response as a HBV vaccine.

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Characterization of Erythropoietin Producing Cell Lines after Introduction of Urea Cycle Enzymes, Carbamoly Phosphate Synthetase and Ornithine Transcarbamoylase

  • Lee, Yun-Jeong;Kim, Na-Young;Kim, Hyung-Jin;Park, Jung-Ho;Kim, Jung-Kwon;Hee, Chang-Kern;Kim, Jung-Hoe;Kim, Hong-Jin
    • Proceedings of the PSK Conference
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    • 2003.10b
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    • pp.170.3-171
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    • 2003
  • An efficient Erythropoietin (EPO)-expression system in mammalian cells is required for massive production for therapeutic use. Ammonium ion is a major problem in the production of valuable recombinant proteins in cultured animal cells. Therefore, it is of importance to devise a system by which a high productivity of human therapeutic recombinant protein can be maintained or enhanced under low ammonium concentration. To reduce the ammonium ion accumulated in EPO producing Chinese Hamster Ovary (CHO) ceels, IBE, we introduced the first two genes of the urea cycle, carbamoyl phosphate synthetase (CPSI) and arnithine transcarbamoylase (OTC), into IBE using a stable transfection method. (omitted)

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Preparation of a Hydrophobized Chitosan Oligosaccharide for Application as an Efficient Gene Carrier

  • Son Sohee;Chae Su Young;Choi Changyong;Kim Myung-Yul;Ngugen Vu Giang;Jang Mi-Kyeong;Nah Jae-Woon;Kweon Jung Keoo
    • Macromolecular Research
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    • v.12 no.6
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    • pp.573-580
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    • 2004
  • To prepare chitosan-based polymeric amphiphiles that can form nanosized core-shell structures (nanopar­ticles) in aqueous milieu, chitosan oligosaccharides (COSs) were modified chemically with hydrophobic cholesterol groups. The physicochemical properties of the hydrophobized COSs (COSCs) were investigated by using dynamic light scattering and fluorescence spectroscopy. The feasibility of applying the COSCs to biomedical applications was investigated by introducing them into a gene delivery system. The COSCs formed nanosized self-aggregates in aqueous environments. Furthermore, the physicochemical properties of the COSC nanoparticles were closely related to the molecular weights of the COSs and the number of hydrophobic groups per COS chain. The critical aggregation concentration values decreased upon increasing the hydrophobicity of the COSCs. The COSCs effi­ciently condensed plasmid DNA into nanosized ion-complexes, in contrast to the effect of the unmodified COSs. An investigation of gene condensation, performed using a gel retardation assay, revealed that $COS6(M_n=6,040 Da)$ containing $5\%$ of cholesteryl chloroformate (COS6C5) formed a stable DNA complex at a COS6C5/DNA weight ratio of 2. In contrast, COS6, the unmodified COS, failed to form a stable COS/DNA complex even at an elevated weight ratio of 8. Furthermore, the COS6C5/DNA complex enhanced the in vitro transfection efficiency on Human embryonic kidney 293 cells by over 100 and 3 times those of COS6 and poly(L-lysine), respectively. Therefore, hydrophobized chitosan oligosaccharide can be considered as an efficient gene carrier for gene delivery systems.

Integrin-linked Kinase Functions as a Tumor Promoter in Bladder Transitional Cell Carcinoma

  • Wang, De-Lin;Lan, Jian-Hua;Chen, Liang;Huang, Biao;Li, Zeng;Zhao, Xiu-Min;Ma, Qiang;Sheng, Xia;Li, Wen-Bin;Tang, Wei-Xue
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.6
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    • pp.2799-2806
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    • 2012
  • The aim of this study was to elucidate the role of the integrin-linked kinase (ILK) gene in development of human bladder transitional cell carcinoma (BTCC). Expression of ILK protein and ILK mRNA in 56 cases of human BTCC tissue and in 30 cases of adjacent normal bladder tissue was detected by immunohistochemistry S-P and reverse transcription polymerase chain reaction (RT-PCR), respectively. Four specific miRNA RNAi vectors targeting human ILK were synthesized and transfected into BIU-87 cells by liposome to obtain stable expression cell strains. The influence of ILK on proliferation of BTCC was detected by MTT, FCM on athymic mouse tumorigenesis. The positive rate of ILK protein in BTCC tissue (53.6%) was much higher than adjacent normal bladder tissue (10.0%) (p<0.05). Similarly, expression of ILK mRNA in BTCC tissue ($0.540{\pm}0.083$) was significantly higher than in adjacent normal bladder tissue ($0.492{\pm}0.070$) (p<0.05). MTT showed that the proliferation ability of miRNA-ILK transfected group was clearly decreased (p<0.05), the cell cycle being arrested in G0/G1-S, an tumorigenesis in vivo was also significantly reduced (p<0.05). ILK gene transcription and protein expression may be involved in the development of BTCC, so that ILK might be the new marker for early diagnosis and the new target for gene treatment.

Developing New Mammalian Gene Expression Systems Using the Infectious cDNA Molecular Clone of the Japanese Encephalitis Virus

  • Yun Sang-Im;Choi Yu-Jeong;Park Jun-Sun;Kim Seok-Yong;Lee Young-Min
    • Proceedings of the Microbiological Society of Korea Conference
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    • 2003.05a
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    • pp.83-86
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    • 2003
  • Major advances in positive-sense RNA virus research have been facilitated by the development of reverse genetics systems. These systems consist of an infectious cDNA clone that encompasses the genome of the virus in question. This clone is then used as a template for the subsequent synthesis of infectious RNA for the generation of synthetic viruses. However, the construction of infectious cDNA for the Japanese encephalitis virus (JEV) has been repeatedly thwarted by the instability of its cDNA. As JEV is an important human pathogen that causes permanent neuropsychiatric sequelae and even fatal disease, a reliable reverse genetics system for this virus is highly desirable. The availability of this tool would greatly and the development of effective vaccines as well as facilitate studies into the basic biology of the virus, including the molecular mechanisms of viral replication, neurovirulence, and pathogenesis. We have successfully constructed a genetically stable infectious JEV cDNA containing full-length viral RNA genome. Synthetic RNA transcripts generated in vitro from the cDNA were highly infectious upon transfection into susceptible cells, and the cDNA remained stable after it had been propagated in E. coli for 180 generations. Using this infectious JEV cDNA, we have successfully expressed a variety of reporter genes from the full-length genomic and various subgenomic RNAs in vitro transcribed from functional JEV cDNAS. In summary, we have developed a reverse genetics system for JEV that will greatly facilitate the research on this virus in a variety of different fields. It will also be useful as a heterologous gene expression vector and aid the development of a vaccine against JEV.

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Analysis of the Biological Function of ELDF15 Using an Antisense Recombinant Expression Vector

  • Liu, Yan;Wang, Long;Wang, Zi-Jun
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.21
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    • pp.9131-9136
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    • 2014
  • ELDF15, homologous with AT2 receptor-interaction protein 1 (ATIP1), may play an important role in cell differentiation, proliferation, and carcinogenesis. We aimed to understand the biological function of ELDF15 via construction and transfection of a recombinant expression vector containing antisense ELDF15. Recombinant expression vectors were successfully constructed and transfected into K562 cells. A stable transfectant, known as pXJ41-asELDF15, stably produced antisense ELDF15. Compared with K562 and K562-zeo cells, K562-pXJ41-asELDF15 cells showed inhibition of cell proliferation. RT-PCR analysis showed that the expression and protein level of ELDF15 decreased significantly in K562 cells transfected with pXJ41-asELDF15. Expression of hemoglobin increased in K562 cells transfected with pXJ41-asELDF15 by benzidine staining. increases NBT reduction activity in K562 cells transfected with pXJ41-asELDF15.Colony forming efficiency in two-layer soft agar was clearly inhibited as assessed by electron microscopy. These results suggest that ELDF15 plays a potential role in cell differentiation, proliferation and carcinogenesis.

miR-181b as a Potential Molecular Target for Anticancer Therapy of Gastric Neoplasms

  • Guo, Jian-Xin;Tao, Qing-Song;Lou, Peng-Rong;Chen, Xiao-Chun;Chen, Jun;Yuan, Guang-Bo
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.5
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    • pp.2263-2267
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    • 2012
  • Objective: MicroRNAs (miRNAs) play important roles in carcinogenesis. The aim of the present study was to explore the effects of miR-181b on gastric cancer. Methods: The expression level of miR-181b was quantified by qRT-PCR. MTT, flow cytometry and matrigel invasion assays were used to test proliferation, apoptosis and invasion of miR-181b stable transfected gastric cancer cells. Results: miR-181b was aberrantly overexpressed in gastric cancer cells and primary gastric cancer tissues. Further experiments demonstrated inducible expression of miR-181b by Helicobacter pylori treatment. Cell proliferation, migration and invasion in the gastric cancer cells were significantly increased after miR-181b transfection and apoptotic cells were also increased. Furthermore, overexpression of miR-181b downregulated the protein level of tissue inhibitor of metalloproteinase 3 (TIMP3). Conclusion: The upregulation of miR-181b may play an important role in the progress of gastric cancer and miR-181b maybe a potential molecular target for anticancer therapeutics of gastric cancer.

Enhancement of Erythropoietin Production from Chinese Hamster Ovary(CHO) Cells by Introduction of the Urea Cycle Enzymes, Carbamoyl Phosphate Synthetase I and Ornithine Transcarbamylase

  • Kim, Na-Young;Lee, Yun-Jeong;Kim, Hyung-Jin;Choi, Jung-Ho;Kim, Jung-Kwon;Chang, Kern-Hee;Kim, Jung-Hoe;Kim, Hong-Jin
    • Journal of Microbiology and Biotechnology
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    • v.14 no.4
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    • pp.844-851
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    • 2004
  • Efficient mammalian erythropoietin (EPO)-expression systems are required for therapeutic applications. The accumulation of ammonia is a major problem in the production of recombinant proteins in cultured animal cells. To counter this problem we introduced the first two genes of the urea cycle, carbamoyl phosphate synthetase (CPSI) and ornithine transcarbamylase (OTC), into IBE Chinese Hamster Ovary (CHO) cells by stable transfection. The resulting cell line, CO5, had a higher growth rate and accumulated less ammonia per cell than the parental cell line, IBE. In addition, it produced 2 times more EPO than the parent, and the purified EPO contained a higher proportion of acidic isoforms with approximately 15% more sialic acid.

Ectopic expression of Bcl-2 or Bcl-xL suppresses p-fluorophenylalanine-induced apoptosis through blocking mitochondria-dependent caspase cascade in human Jurkat T cells (Jurkat T 세포에 있어서 ρ-fluorophenylalanine에 의해 유도되는 세포자살의 Bcl-2 및 Bcl-xL에 의한 저해 기전)

  • Han, Kyu-Hyun;Oh, Hyun-Ji;Jun, Do-Youn;Kim, Young-Ho
    • Journal of Life Science
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    • v.13 no.1
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    • pp.118-127
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    • 2003
  • $\rho$-Fluorophenylalanine (FPA), a phenylalanine analog, is able to induce apoptotic cell death of human acute leukemia Jurkat T cells. To better understand the mechanism by which FPA induces apoptotic cell death, the effect of ectopic expression of antiapoptotic proteins, Bcl-2 and Bcl-xL, on FPA-induced apoptosis was investigated by employing lurkat T cells transfected with Bcl-2 gene (JT/Bcl-2) or Bcl-xL gene (1/Bcl-xL) and Jurkat T cells transfected with vector (JT/Neo or J/Neo). When Jurkat T cells, JT/Neo or J/Neo, were exposed to FPA at concentrations ranging from 0.63 to 5.0 mM, the cell viability determined by MTT assay declined in a dose-dependent manner. In addition, apoptotic DNA fragmentation along with several apoptotic events such as caspase-8 activation, Bid cleavage, mitochondrial cytochrome c release, caspase-9 activation, caspase-3 activation, and degradation of PARP was induced. However, the FPA-induced cytotoxic effect, activation of caspase-8, and cleavage of Bid were significantly abrogated by ectopic expression of Bcl-2 or Bcl-xL. At the same time, there was marked reduction in the level of cytochrome c release from mitorhondria, caspase-9 activation, caspase-3 activation, and degradation of PARP. These results indicate that caspase-8 activation, Bid cleavage, and mitochondrial cytochrome c release with subsequent activation of the caspase cascade are negatively regulated by Bcl-2 or Bcl-xL, and are thus required for FPA-induced apoptosis in Jurkat T cells

Polyethyleneimine based Delivery System Coated with Hyaluronate Amine for Improved pDNA Transfection Efficiency (개선된 플라스미드 DNA 전달 효율을 위한 히알루론 아민 코팅 폴리에틸렌이민 기반 전달 시스템)

  • Oh, Kyoung-yeon;Jang, Yongho;Lee, Eunbi;Kim, Tae-ho;Kim, Hyuncheol
    • Applied Chemistry for Engineering
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    • v.33 no.1
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    • pp.83-89
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    • 2022
  • Since the pandemic of COVID-19, active investigation to develop immunity to infectious disease by delivering nucleic acids has been proceeded. Particularly, many studies have been conducted on non-viral vector as several vital side-effects which were found on nucleic acid delivery system using viral vectors. In this study, we have developed plasmid DNA (pDNA) loaded-hyaluronic acid derivative (HA) coated-polyethyleneimine (PEI) based polyplex for enhanced nucleic acid delivery efficiency. We have optimized the ratio of pDNA : PEI : HA by measuring size and protein transcription efficiency. The final product, polyplex-HA, was characterized through measuring size, zeta-potential and TEM image. Intracellular uptake and protein transcription efficiency were compared to commercially available transfection reagent, lipofectamine, through fluorescence image and flow cytometry. In conclusion, polyplex-HA presents a novel gene delivery system for efficient and stable protein transcription since it is available for delivering various genetic materials and has less immunoreactivity.