• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.1-9
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• 2000

The rapid progress of molecular genetic methods over the past two decades has necessitated the development of methods to detect and quantify genetic activity within living bodies. Reporter genes provide a rapid and convenient tool to monitor gene expression by yielding a readily measurable phenotype upon expression when introduced into a biological system. Conventional reporter systems, however, are limited in their usefulness for in vivo experiments or human gene therapy because of its invasive nature which requires cell damage before assays can be performed. This offers an unique opportunity for nuclear imaging techniques to develope a novel method for imaging both the location and amount of gene expression noninvasively. Current developments to achieve this goal rely on utilizing either reporter enzymes that accumulate radiolabeled substrates or reporter receptors that bind specific radioligands. This overview includes a brief introduction to the background for such research, a summary of published results, and an outlook for future directions.

• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.83.2-83.2
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• 2008

• The Journal of Natural Sciences
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• v.9 no.1
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• pp.31-37
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• 1997

Apoptosis is an important event in the anticancer drug therapy. p53 was demonstrated to serve a key component to lead tumor cell death by inducing apoptosis. However, recent study showed the presence of p53 independent apoptotic pathway (Gaftenhaus et al., 1996). We were curious to know it apoptosis induced by adriamycin, a genotoxic anticancer agent, involved p53 gene mutation. Thus this study investigated the p53 gene mutation status among HeLa cell population during apoptosis induced by adriamycin. Under our experimental condition, 12 hour treatment of 1 ${\mu}m$ adriamycin caused apoptosis which was monitored by DNA fragmentation assay. In order to see the p53 gene mutation status, exons of 5, 7 and 8 of p53 gene, where previously reported p53 mutation hot spots reside, were amplified by PCR and nucleotide sequence change was scanned. However, no nucleotide change was observed among apoptotic HeLa cell population. Therefore this study demonstrated that adriamycin induced apoptosis without causing p53 gene damage.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2589-2593
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• 2013

Gene therapy using nonviral gene delivery carriers has focused on the development and modification of synthetic carriers such as liposomes and polymers. Most polymers that are commercially used are taking advantage of their polycationic character which allows not only strong ligand-DNA affinity but also competent cell penetration. Despite the relatively high transfection efficiencies, high cytotoxicity is continuously pointed out as one of the major shortcomings of polycationic polymers such as PEI. Studies on the utilization of peptides have therefore been carried out recently to overcome these problems. For these reasons, the human transcription factor Hph-1, which is currently known as a protein transduction domain (PTD), was investigated in this study to evaluate its potential as a gene delivery carrier. Although its transfection efficiency was about 10-fold lower than PEI, it displayed almost no cytotoxicity even at concentrations as high as $100{\mu}M$. Hph-1 was oxidatively polymerized to yield poly-Hph-1. The cell viability of poly-Hph-1 transfected U87MG and NIH-3T3 cells was almost as high as the control (untreated) groups, and the transfection efficiency was about 10-fold higher than PEI. This study serves as a preliminary evaluation of Hph-1 and encourages further investigation.

• Tuberculosis and Respiratory Diseases
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• v.45 no.3
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• pp.587-595
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• 1998

Background: Recombinant adenovirus hold promise as vectors to carry therapeutic genes for several reasons: 1) they can infect both dividing and non-dividing cells; 2) they have the ability to directly transduce tissues in vivo; 3) they can easily be produced in high titer; and 4) they have an established record of safety as vaccination material. However, one of the major limitation in the use of adenoviruses is that transgene expression is quite short because adenovirusees insert their DNA genome episomally rather than by chromosomal integration, and an immune response against the virus destroys cells expressing the therapeutic gene. Since sodium butyrate has been reported to induce adenovirus-mediated gene expression, we hypothesized that treatment of tumor cells, transduced with herpes simples virus thymidine kinase(HSVtk) gene using adenoviral vector, with butyrate could augment the effect of gene therapy. Methods: We transduced HSVtk gene, driven by the cytomegalovirus promoter, into REN cell line(human mesothelioma cell line). Before proceeding with the comparison of HSVtk/ganciclovir mediated bystander killing, we evaluated the effect of butyrate on the growth of tumor cells in order to rule out a potential antitumor effect of butyrate alone, and also on expression of HSVtk gene by Western blot analysis. Then we determined the effects of butyrate on bystander-mediated cell killing in vitro. Results: There was no inhibition of growth of cells exposed to butyrate for 24 hours at a concentration of 1.5mM/L. Toxic effects were seen when the concentration of butyrate was greater than 2.0mM/L. Gene expression was more stable and bystander effect was augmented by butyrate treatment of a concentration of 1.5mM/L. Conclusion: These results provide evidence that butyrate can augment the efficiency of cell killing with HSVtk/GCV system by inducing transgene expression and may thus by a promising new approach to improve responses in gene therapy using adenoviral vectors.

• Annals of Clinical Neurophysiology
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• v.23 no.1
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• pp.29-34
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• 2021

New therapeutics in neurology are expanding at an unprecedented pace. In addition to the classic enzyme-replacement therapies, monoclonal antibodies are increasingly being used to modulate autoimmunity. RNA therapeutics are an emerging class, together with gene and cell therapies. The nomenclature of international nonproprietary names helps us to recognize these new drugs according to their class and function. Suffixes denote major categories of the drug, while infixes provide additional information such as the source and target.

• Journal of Pharmaceutical Investigation
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• v.33 no.4
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• pp.267-272
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• 2003

Herpes simplex virus (HSV) thymidine kinase (TK) has been widely used for suicidal gene therapy in combination with nucleoside analogs such as ganciclovir (GCV). The use of HSV-TK is limited due to the side effect of GCV at high concentrations. Previous studies showed that stable transfectants of mutant HSV-TK with enhanced affinity to GCV were killed at lower GCV concentrations. In this study, we tested whether mutant HSV-TK can provide enhanced suicidal effect when transiently transfected with Epstein-Barr virus (EBV)-based plasmid. EBV-based plasmid which contains OriP and EBNA-1 sequence is well known for a stable episomal maintenance in human cells. Optimal transfection condition was assessed for SNU-638 gastric cancer cell line using polyetylnimine (PEI). Maximum transfection efficiency was achieved when DNA:PEI was 1:3 (w/v). Cytotoxicities of mutant and wild type HSV-TK were compared before and after partially selecting transfected cells. The cells were sensitive to $100\;{\mu}g/ml$ hygromycin. Following GCV treatment, more cells were killed after hygromycin selection than before selection. The mutant HSV-TK showed enhanced cytotoxicity compared with the wild type HSV-TK. Our results suggest that the EBV-based plasmid encoding mutant HSV-TK may be useful to treat the diseases caused by uncontrolled cell proliferation such as cancer and rheumatoid arthritis.

• Journal of Yeungnam Medical Science
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• v.20 no.2
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• pp.142-151
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• 2003

To induce bone formation at ectopic site by tissue engineering and gene therapy, we transplanted collagen sponges containing rhBMP-7 transduced HEK 293 cells in the hypodermis of nude mice. Bone formation was investigated by histological and electron microscopic method at 3, 6, and 9 weeks after transplantation. At 9 weeks after transplantation, eosinophilic bony tissue was observed in the implanted collagen sponge and was confirmed as bone tissue by Von Kossa stain. In the transmission electron microscopic observation, the cells in newly formed bone tissue had eccentrically located nucleus and well developed rough endoplasmic reticulum (rER). Therefore, the cells were evaluated as osteoblasts. Those results suggest that it is possible to form a bone tissue in the ectopic site by transplantation of rhBMP-7 transduced HEK 293 cells. This will be contributed to push more advanced gene therapy for bone formation. However, the HEK 293 cell is unable to apply to the clinical gene therapy. Therefore it is worth to find more compatible cells for clinical application. In addition, collagen sponge is considered as an excellent scaffold and/or carrier for gene therapy and a good biomaterial for tissue engineering.

• Tuberculosis and Respiratory Diseases
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• v.44 no.6
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• pp.1271-1284
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• 1997

Background : Tumor necrosis factor(TNF) has been considered as an important candidate for cancer gene therapy based on its potent anti-tumor activity. However, since the efficiency of current techniques of gene transfer is not satisfactory, the majority of current protocols is aiming the in vitro gene transfer to cancer cells and re-introducing genetically modified cancer cells to host. In the previous study, it was shown that TNF-sensitive cancer cells transfected with TNF-$\alpha$ cDNA would become highly resistant to TNF, and the probability was shown that the acquired resistance to TNF might be associated with synthesis of some protective protein. Understanding the mechanisms of TNF-resistance in TNF-$\alpha$ cDNA transfected cancer cells would be an important step for improving the efficacy of cancer gene therapy as well as for better understandings of tumor biology. This study was designed to evaluate whether the levels of TNF receptor mRNA expression and soluble TNF receptor release from cancer cells are changed after TNF-$\alpha$ cDNA transfection. Method : We transfected TNF-$\alpha$ c-DNA to WEHI164(murine fibrosarcoma cell line), NCI-H2058(human mesothelioma cell line), A549(human non-small cell lung cancer cell line), ME180(human cervix cancer cell line) cells using retroviral vector(pLT12SN(TNF)) and confirm the expression of TNF with PCR, EUSA, MTT assay. Then we determined the TNF resistance of TNF-$\alpha$ cDNA transfected cells(WEHI164-TNF, NCIH2058-TNF, A549-TNF, ME180-TNF) and evaluated the TNF receptor mRNA expression with Northern blot analysis and soluble TNF receptor release with EUSA. Results : The TNF receptor mRNA expressions of parental cells and genetically modified cells were not significantly different. The soluble TNF receptor levels of media from genetically modified cells were lower than those from parental cells. Conclusion : The acquired resistance to TNF after TNF-$\alpha$ cDNA transfection may not be associated with the change in the TNF receptor and the soluble TNF receptor expression.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7435-7439
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• 2015

A failure of a cell to self destruct has long been associated with cancer progression and development. The fact that tumour cells may not instigate cell arrest or activate cell death mechanisms upon cancer drug delivery is a major concern. Autophagy is a mechanism whereby cell material can be engulfed and digested while apoptosis is a self-killing mechanism, both capable of hindering multiplication after cell injury. In particular situations, autophagy and apoptosis seem to co-exist simultaneously or interdependently with the aid of mutual proteins. This review covers roles of microRNAs and chemopreventive agents and makes an attempt at outlining possible partnerships in maximizing cancer cell death with minimal normal cell damage.