• YAKHAK HOEJI
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• v.49 no.3
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• pp.217-224
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• 2005

Human Immunodeficiency Virus type 1 (HIV-l) based lentivirus vector has demonstrated great potential as gene therapy vectors mediating efficient gene delivery and long-term transgene expression in both dividing and nondividing cells. However, for clinical studies it must be confirmed that vector preparations are safe and not contaminated by replication competent lentivirus (RCL) related to the parental pathogenic virus, HIV-l. In this study, we would like to establish the method for titration and RCL detection of lentivirus vector. The titration was determined by vector expression containing the green fluorescent protein, GFP in transduced cells. The titer was $1{\times}10^7$ Transducing Unit/ml in the GFP expression assay and $8.9{\times}10^7$ molecules/ml in the real-time PCR. Also, for the detection of RCL, we have used a combination method of PCR and p24 antigen detection. First, PBS/psi and VSV-G region in the genomic DNA of transduced cells was detected by PCR assay. Second, transfer and expression of the HIV-1 gag gene was detected by p24 ELISA. In an attempt to amplify any RCL, the transduced cells were cultured for 3 weeks (amplification phase) and the supernatant of amplified transduced cell was used for the second transduction to determine whether a true RCL was present (indicator phase). Analysis of cells and supernatant at day 6 in indicator phase were negative for PBS/psi, VSV-G, and p24 antigen. These results suggest that they are not mobilized and therefore there are no RCL in amplification phase. Thus, real-time PCR is a reliable and sensitive method for titration and RCL detection of lentivirus vector.

• Reproductive and Developmental Biology
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• v.32 no.1
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• pp.15-20
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• 2008

Pronuclear DNA microinjection has been the most universal method in transgenic animal production but its success rate of transgenesis in mammals are extremely low. To address this long-standing problem, we used retrovirus- and lentivirus-based vectors carrying the enhanced green fluorescent protein (EGFP) gene under the control of ubiquitously active cytomegalovirus (CMV) promoter to deliver transgenes to bovine embryos. The rate of transgenesis was evaluated by counting EGFP positive blastocysts after injection of concentrated virus stock into the perivitelline space of the bovine oocytes in metaphase II. Among two different types of lentivirus vectors derived from FIV (feline immunodeficiency virus) and HIV (human immunodeficiency virus), the former scored the higher gene transfer efficiency; almost 100% of the blastocysts developed from the oocytes infected with FIV-based vector were EGFP positive. As for the vectors derived Com HIV lentivirus, the transgenesis rate of the blastocysts was reduced to 39%.

• Biomedical Science Letters
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• v.25 no.4
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• pp.398-406
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• 2019

Cancer immunotherapy using gene-modified tumor cells is safe and customized cancer treatment method. In this study, we made gene-modified tumor cells by transferring costimulatory molecules, 4-1BBL and OX40L, into tumor cells using lentivirus vector, and identified anti-cancer effect of gene-modified tumor cells in CT26 mouse colorectal tumor model. We construct pLVX-puro-4-1BBL, -OX40L vector for lentivirus production and optimized the transfection efficiency and transduction efficiency. The transfection efficiency is maximal at DNA:cationic polymer = 1:0.5 and DNA 2 ㎍ for lentivirus production. Then, the lentiviral including 4-1BBL and OX40L was used to deliver CT26 mouse tumor cells to establish optimal delivery conditions according to the amount of virus. The transduction efficiency is maximal at 500 μL volume of lentiviral stock without change in cell shape or growth rate. CT26-4-1BBL, CT26-OX40L significantly inhibited the tumor growth compare with CT26-WT or CT26-β-gal cell line. These data showed the possibility the use of genetically modified tumor cells with costimulatory molecule as cancer immunotherapy agent.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.611-616
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• 2014

Objectives: Dendritic cell (DC)-based tumor immunotherapy needs an immunogenic tumor associated antigen (TAA) and an effective approach for its presentation to lymphocytes. In this study we explored whether transduction of DCs with lentiviruses (LVs) expressing the human interleukin-12 gene could stimulate antigen-specific cytotoxic T cells (CTLs) against human lung cancer cells in vitro. Methods: Peripheral blood monocyte-derived DCs were transduced with a lentiviral vector encoding human IL-12 gene (LV-12). The anticipated target of the human IL-12 gene was detected by RT-PCR. The concentration of IL-12 in the culture supernatant of DCs was measured by ELISA.Transduction efficiencies and CD83 phenotypes of DCs were assessed by flow cytometry. DCs were pulsed with tumor antigen of lung cancer cells (DC+Ag) and transduced with LV-12 (DC-LV-12+Ag). Stimulation of T lymphocyte proliferation by DCs and activation of cytotoxic T-lymphocytes (CTL) stimulated by LV-12 transduced DCs pulsed with tumor antigen against A549 lung cancer cells were assessed with methyl thiazolyltetrazolium (MTT). Results: A recombinant lentivirus expressing the IL-12 gene was successfully constructed. DC transduced with LV-12 produced higher levels of IL-12 and expressed higher levels of CD83 than non-transduced. The DC modified by interleukin -12 gene and pulsed with tumor antigen demonstrated good stimulation of lymphocyte proliferation, induction of antigen-specific cytotoxic T lymphocytes and antitumor effects. Conclusions: Dendritic cells transduced with a lentivirus-mediated interleukin-12 gene have an enhanced ability to kill lung cancer cells through promoting T lymphocyte proliferation and cytotoxicity.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5391-5396
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• 2013

Aim: To investigate the role of Golgi phosphoprotein 3 (GOLPH3) in tumour growth and metastasis of esophageal squamous cancer. Methods: A lentiviral shRNA-vector was utilized to stably knockdown GOLPH3 in Eca-109 esophageal squamous cancer cells. mRNA transcription and protein expression of GOLPH3 were examined by real-time quantitative PCR and Western blotting, respectively. Cell proliferation activity was assessed by MTT assay and invasion and migration potentials by matrigel invasion and transwell motility assays. Results: Stable knockdown in the GOLPH3 cell line was established. PD-A gene expression was significantly suppressed by lentivirus-mediated RNAi, which resulted in reducing the capacity for cell proliferation, migration, invasion and adhesion in vitro. In vivo, GOLPH3 depletion resulted in inhibition of tumour growth, with stable decrease in the expression of GOLPH3 in tumor xenografts. Conclusions: Our findings suggest that lentivirus mediated silencing of the GOLPH3 gene has a significant anti-tumour effect on esophageal squamous cancer in vitro and in vivo. In addition, the results indicate that GOLPH3 might be an effective molecular target for gene therapy in esophageal squamous cancer.

• Molecules and Cells
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• v.24 no.1
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• pp.125-131
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• 2007

von Willebrand factor (vWF) is a multimeric glycoprotein which functions within the coagulation system. It colocalizes with factor VIII (FVIII) by non-covalent interaction and alters its intracellular trafficking. vWF is also instrumental in maintaining the stability of secreted FVIII. The principal objective of this study was to generate a lentivirus-based vWF expression vector for gene therapy of hemophilia A. We inserted a vWF of 8.8 Kb into a lentiviral vector thereby producing VSV-G-pseudotyped vEx52. However, its titer was quite low, presumably because the length of vWF gene exceeds the size limit of the lentiviral vector. In order to overcome the low-titer, we concentrated the vEx52 and thus increased the efficiency of transduction approximately 6-fold with $1/100^{th}$ of the volume. However, as concentration requires an additional laborious step, we attempted to enhance the transduction efficiency by deleting exons 24-46 and 29-46 in pRex52 to construct pRex23 and pRex28, and in pvEx52, yielding pvEx23 and pvEx28, respectively. The transfected pRex52 had a profound effect on the activity of secreted FVIII, and this activity declined as domains of vWF were deleted. However, when the domain-deleted vWF-lentiviruses were transduced into K562 cells, the vEx28 increased the activity of the secreted FVIII compared to what was observed with vEx52. This result is probably due to higher efficiencies of transduction and expression while retaining the essential domains required for proper interaction with FVIII.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.2
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• pp.81-85
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• 2007

Glucocorticoid hormone regulates numerous physiological processes, such as regulation of metabolism, and anti-inflammatory and immunosuppressive actions via the activation and repression of gene expression. Here we described a lentivirus-based reporter vector system expressing red fluorescent protein (mRFP) or firefly luciferase (Luc) under the control of a glucocorticoid-responsive element that allows observation of the temporospatial pattern of glucocorticoid induced GR-mediated signaling on a cellular level. Moreover, usage of the chromatin insulator of the chicken ${\beta}$-globin locus induced a marked increase of sensitivity of glucocorticoid inducible promoter of a reporter gene. Use of this method will be applicable of screening for agonist and antagonist of GR in vitro, and also a reporter gene assay for the in vivo determination of the GR-mediated gene activation.

• Reproductive and Developmental Biology
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• v.31 no.3
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• pp.153-159
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• 2007

In this study, using FIV-based lentivirus vector system, we tried to express hG-CSF in tetracycline-controllable manner. hG-CSF influences the proliferation, differentiation, and survival of cells in the neutrophil lineage. To enhance stability and translation of hG-CSF transcript, WPRE sequence was also introduced into FIV-Tet-On vector at downstream region of either the hG-CSF gene or the sequence encoding rtTA. Primary culture cells (CEF, chicken embryonic fibroblast; PFF, procine fetal fibroblast) infected with the recombinant FIV were cultured in the medium supplemented with or without doxycycline for 48 hours, and induction efficiency was measured by comparing the hG-CSF gene expression level using quantitative real-time PCR, Western blot and ELISA. Higher hG-CSF expression and tighter expression control were observed from the vector in which the WPRE sequence was placed at downstream of the hG-CSF (in CEF) or rtTA (in PEE) gene. This FIV-Tet-On vector system may be helpful in solving serious physiological disturbance problems which has continuously hampered successful production of transgenic animals and gene therapy.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.10
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• pp.4947-4951
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• 2012

Objective: Lung cancer is a deadly cancer, whose kills more people worldwide than any other malignancy. SLUG (SNAI2, Snail2) is involved in the epithelial mesenchymal transition in physiological and in pathological contexts and is implicated in the development and progression of lung cancer. Methods: We constructed a lentivirus vector with SLUG shRNA (LV-shSLUG). LV-shSLUG and a control lentivirus were infected into the non-small cell lung cancer cell A549 and real-time PCR, Western blot and IHC were applied to assess expression of the SLUG gene. Cell proliferation and migration were detected using MTT and clony formation methods. Results: Real-time PCR, Western Blot and IHC results confirmed down-regulation of SLUG expression by its shRNA by about 80%~90% at both the mRNA and protein levels. Knockdown of SLUG significantly suppressed lung cancer cell proliferation. Furthermore, knockdown of SLUG significantly inhibited lung cancer cell invasion and metastasis. Finally, knockdown of SLUG induced the down-regulation of Bcl-2 and up-regulation of E-cadherin. Conclusion: These results indicate that SLUG is a newly identified gene associated with lung cancer growth and metastasis. SLUG may serve as a new therapeutic target for the treatment of lung cancer in the future.

• Journal of Ginseng Research
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• v.47 no.1
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• pp.123-132
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• 2023

Background: Pseudotyped virus systems that incorporate viral proteins have been widely employed for the rapid determination of the effectiveness and neutralizing activity of drug and vaccine candidates in biosafety level 2 facilities. We report an efficient method for producing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pseudovirus with dual luciferase and fluorescent protein reporters. Moreover, using the established method, we also aimed to investigate whether Korean Red Ginseng (KRG), a valuable Korean herbal medicine, can attenuate infectivity of the pseudotyped virus. Methods: A pseudovirus of SARS-CoV-2 (SARS-2pv) was constructed and efficiently produced using lentivirus vector systems available in the public domain by the introduction of critical mutations in the cytoplasmic tail of the spike protein. KRG extract was dose-dependently treated to Calu-3 cells during SARS2-pv treatment to evaluate the protective activity against SARS-CoV-2. Results: The use of Calu-3 cells or the expression of angiotensin-converting enzyme 2 (ACE2) in HEK293T cells enabled SARS-2pv infection of host cells. Coexpression of transmembrane protease serine subtype 2 (TMPRSS2), which is the activator of spike protein, with ACE2 dramatically elevated luciferase activity, confirming the importance of the TMPRSS2-mediated pathway during SARS-CoV-2 entry. Our pseudovirus assay also revealed that KRG elicited resistance to SARS-CoV-2 infection in lung cells, suggesting its beneficial health effect. Conclusion: The method demonstrated the production of SARS-2pv for the analysis of vaccine or drug candidates. When KRG was assessed by the method, it protected host cells from coronavirus infection. Further studies will be followed for demonstrating this potential benefit.