• The Korean Journal of Nuclear Medicine
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• v.38 no.1
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• pp.62-73
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• 2004

Purpose: The herpes simplex virus type 1 thymidine kinase gene(HSV1-tk) is an attractive candidate as a reporter gene in noninvasive reporter gene monitoring system. The HSV1-tk gene was chosen as a reporter gene, because it has been extensively studied, and there are appropriate reporter probes, substrates of HSV1-tk gene product, to apply for HSV1-tk gene imaging. We used radiolabeled 5-iodovinyl-2'-deoxyuridine (IVDU) and 5-iodovinyl-2'-fluoro-2'-deoxyuridine (IVFRU) as reporter probes for HSV1-tk gene monitoring system. Materials and Methods: We prepared HSV1-tk gene transduced Morris hepatoma cell line using retroviral vector, MOLTEN containing HSV1-tk gene. And we confirmed the HSV1-tk gene expression by Northern blotting and Western blotting. We compared in vitro uptakes of radioiodinated IVDU and IVFRU to monitor HSV1-tk gene expression in Morris hepatoma cell line (MCA) and HSV1-tk gene tranduced MCA (MCA-tk) cells until 480 minutes. We also peformed correlation analysis between percentage of HSV1-tk gene tranduced MCA cell % (MCA-tk%) and uptakes of radiolabeled IVDU or IVFRU. Results: MCA-tk cell expressed HSV1-tk mRNA and HSV1-TK protein. Two compounds showed minimal uptake in MCA, but increased uptake was observed in MCA-tk. IVDU showed 4-fold higher accumulation than IVFRU at 480 min in MCA-tk (p<0.01). Both IVDU and IVFRU uptake were linearly correlated ($R^2>0.96$) with increasing MCA-tk%. Conclusion: The radiolabeld IVDU and IVFRU showed higher specific accumulation in retrovirally HSV1-tk gene transfected Morris hepatoma cell line. Both IVDU and IVFRU could be used as good substrates for evaluation of HSV1-tk gene expression.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.71-75
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• 1990

Yoghurt was prepared with Bifidobacterium longum TK-100 and Lactobacillus acidophilus TK-2070. The prepared yoghurt showed the increase of the titratable acidity under cold storage condition. This was derived from the active L. acidophilus TK-2070 on the logarithmic phase rather than from the B. longumn TK-2070. B. longum TK-100 grew well in the facultative anaerobic condition as well as in the strict anaerobic condition. Reinforced clostridial agar medium with 0.1% aniline blue was tried for the differential viable cell counts in the mixed culture and in the yoghurt. B. longurn TK-2070 had the light gray, blue-dotted colonies of about 2 mm diameter. L. acidophilus TK-2070 had the light gray colonies of about 1 mm diameter.

• Proceedings of the Korean Society of Toxicology Conference
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• 1998.10a
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• pp.50-50
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• 1998

• Molecules and Cells
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• v.45 no.7
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• pp.479-494
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• 2022

Human mesenchymal stem cells (MSCs) are multipotent stem cells that have been intensively studied as therapeutic tools for a variety of disorders. To enhance the efficacy of MSCs, therapeutic genes are introduced using retroviral and lentiviral vectors. However, serious adverse events (SAEs) such as tumorigenesis can be induced by insertional mutagenesis. We generated lentiviral vectors encoding the wild-type herpes simplex virus thymidine kinase (HSV-TK) gene and a gene containing a point mutation that results in an alanine to histidine substitution at residue 168 (TK(A168H)) and transduced expression in MSCs (MSC-TK and MSC-TK(A168H)). Transduction of lentiviral vectors encoding the TK(A168H) mutant did not alter the proliferation capacity, mesodermal differentiation potential, or surface antigenicity of MSCs. The MSC-TK(A168H) cells were genetically stable, as shown by karyotyping. MSC-TK(A168H) responded to ganciclovir (GCV) with an half maximal inhibitory concentration (IC₅₀) value 10-fold less than that of MSC-TK. Because MSC-TK(A168H) cells were found to be non-tumorigenic, a U87-TK(A168H) subcutaneous tumor was used as a SAE-like condition and we evaluated the effect of valganciclovir (vGCV), an oral prodrug for GCV. U87-TK(A168H) tumors were more efficiently ablated by 200 mg/kg vGCV than U87-TK tumors. These results indicate that MSC-TK(A168H) cells appear to be pre-clinically safe for therapeutic use. We propose that genetic modification with HSV-TK(A168H) makes allogeneic MSC-based ex vivo therapy safer by eliminating transplanted cells during SAEs such as uncontrolled cell proliferation.

• Journal of Haehwa Medicine
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• v.12 no.2
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• pp.227-234
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• 2004

The international government committee is progressing their agreements about intellectual property protection of traditional knowledge(TK), gene resource(GR), folklore(FL) in WIPO. It is in the course of selection with precedence of TK, GR, FL in WIPO, focused on discussions about listing of TK documents, standardization of DB construction, sharing and profit distribution of GR. There are disagreements between developed countries and developing countries about intellectual property protection agreements of TK, GR. The developed countries insist on using the existing intellectual property protection, but the developing countries ask new ones on character of TK, GR. It causes intangible assets to be valuable trade properties in future world trade. This research Groped for a summary program about intellectual property protection of traditional knowledge(TK) etc. debating in WIPO. This program confirms that such as TK, GR etc. not only to be the cultural property accumulated in human history, but also to be the original resource may be using at present. Therefore, we suggest that the focus of discussion should transfer to UNESCO instead of WIPO which only deal with the intellectual property protection. Besides, the main body which protecting and supporting TK should become its holding organization so as to achieve more effective management about it. In order to protect and support TK, the government should have firstly the recognition that TK is the property belongs to the country. By this viewpoint, it needs to setup DB through overall excavation of the unofficial knowledges in order to protect and support these TK, GR. Because the positive dealing with those WIPO's discussion means to support our TK, GR, so there should have some reorganization about existing related ones, and also needs systemic supporting policies & management' system.

• Tuberculosis and Respiratory Diseases
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• v.49 no.3
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• pp.298-309
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• 2000

Background : The antitumor effects of herpes simplex virus thymidine kinase (HSV-tk) and ganciclovir (GCV) strategies for cancer gene therapy have a the following advantages : 1) a direct cytotoxicity to HSV-tk modified cancer cells by GCV 2) a cell death by the local transfer of toxic metabolites from the HSV-tk modified cells to nearby unmodified tumor cells (bystander effect), and 3) in vivo bystander effect such as antitumor-immunity. Retroviral and adenoviral sequences can silence transgene expression in cells and mice. In this study, we investigated the above described advantages of HSV-tk/GCV strategy in Lewis lung cell and mouse lung cancer model using retroviral vector and adenoviral vector. Also, we observed whether the expression of a silenced gene can be reactivated by treating cells with butyrate. Methods : Retrovirus-HSV-tk and adenovirus-HSV-tk vectors were used for the transduction of Lewis lung carcinoma (LLC) cells. The change of HSV-tk expression by butyrate was measured by Western blol The antitumor activities containing bystander effect were observed in vivo (by MTT assay) and in vivo tumor models of various combinations of LLC and LLC-tk. Results : 1. Butyrate induced the enhancement of HSV-tk expression from adenovirally transduced cells but not from retrovirally transduced cells. 2. Both retrovirus-HSV-tk and adenovirus-HSV-tk vectors with GCV treatment were effective for killing of tumor cell in vitro and suppression of LLC tumorigenicity. Bystander effect was responsible for killing of mixture of LLC-tk and LLC in vitro and in vivo-tumorigenicity model. Conclusion : Butyrate could augment adenovirus-mediated HSV -tk gene expression. Cancer gene therapy with HSV-tk suicide gene by retroviral and adenoviral vector seems to be an effective approach for lung cancer therapy.

• Korean Journal of Oriental Medicine
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• v.9 no.1
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• pp.51-63
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• 2003

The international government committee is progressing their agreements about intellectual property protection of traditional knowledge(TK), gene resource(GR), folklore(FL) in WIPO. It is in the course of selection with precedence of TK, GR, FL in WlPO, focused on discussions about listing of TK documents, standardization of DB construction, sharing and profit distribution of GR. Their are disagreements between developed countries and underdeveloped countries about intellectual property protection agreements of TK, GR. The developed countries insist on using, the existing intellectual property protections, but the underdeveloped countries ask new ones on character of TK, GR, It causes intangible assets to be valuable trade properties in future world trade. We have to make national plans to face agreements about IP of TK, GR in WIPO with our own TK, GR. We must have a basic attitude about laying down these plans such as raising national economy, considering our TK, GR to be relics of mankind culture. In addition to these, it needs accurate analysis about agreements in WIPO, our TK, GR, scientific mechanical level and capital power.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.10a
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• pp.9-15
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• 1995

When quiescent cells ate stimulated to enter the cell cycle, the thymidine kinase(TK) gene is transcriptionally activated at the border of Gl and 5. In this report we show that the human TK promoter contains multiple protein-binding sites. By site-directed mutagenesis, we identified a protein-binding site on the human TK promoter requited for conferring Gl-S-regulated transcription to a heterologous promoter and dissociated it functionally from an adjacent protein-binding domain containing an inverted CCAAT motif requited for high basal level expression. Substitution-mutation of this site results in constitutive expression of the neo reporter gene in serum-stimulated fibroblasts, as well as in cells arrested in mid-Gl by a temperature-sensitive mutation. The regulatory domains for the human TK promoter exhibit interesting symmetrical features, including a set of CCAAT motifs and sites similar to the novel Yi protein-binding site recently discovered in the mouse TK promoter. Thus, components of the hTK complex is important for hTK gene regulation.

• Journal of Animal Environmental Science
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• v.11 no.2
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• pp.111-116
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• 2005

The purpose of this study was to analyze the performance of vehicle disinfector nozzles using at the livestock farm. The nozzle of vehicle disinfectors was measured spraying rate and equality distribution ratio by pressures. The spraying rate of TK-I's nozzle was 1,605 ml/min at 3 MPa, TK-II's nozzle was 2,020 ml/min, JA's nozzle was 1,150 ml/min and IS's nozzle was 795 ml/min. The number of nozzles of TK-I's, TK-II's, JA's and IS's for reasonable spraying rate($25{\ell}/min$. at 3 MPa) was respectively 16, 13, 22 and 32 units. The equality distribution ratio of TK-I's nozzle by pressures was equalized and the nozzles of TK-II's, JA's and IS's was sprayed to the center or side more then other sides in the measured boxes.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.235-245
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• 2008

Purpose: The HSV1-tk gene has been extensively studied as a type of reporter gene. In hepatocellular carcinoma (HCC), only a small proportion of patients are eligible for surgical resection and there is limitation in palliative options. Therefore, there is a need for the development of new treatment modalities and gene therapy is a leading candidate. In the present study, we investigated the usefulness of substrate, 2'-fluoro-2'-deoxy-1-${\beta}$-D-arabino-furanosyi-5-[$^{124/125}I$]iodo- uracil ([$I^{124/125}I$]FIAU) as a non-invasive imaging agent for HSV1-tk gene therapy in hepatoma model using small animal PET. Material and Methods: With the Morris hepatoma MCA cell line and MCA-tk cell line which was transduced with the HSV1-tk gene, in vitro uptake and correlation study between [$^{125}I$]FIAU uptake according to increasing numeric count of percentage of MCA-tk cell were performed. The biodistribution data and small animal PET images with [$^{124}I$]FIAU were obtained with Balb/c-nude mice bearing both MCA and MCA-tk tumors. Results:, Specific accumulation of [[$^{125}I$]FIAU was observed in MCA-tk cells but uptake was low in MCA cells. Uptake in MCA-tk cells was 15 times higher than that of MCA cells at 480 min. [$^{125}I$]FIAU uptake was linearly correlated (R2 =0.964, p =0.01) with increasing percentage of MCA-tk numeric cell count. Biodistribution results showed that [$^{125}I$]FIAU was mainly excreted via the renal system in the early phase. Ratios of MCA-tk tumor to blood acting were 10, 41, and 641 at 1 h, 4 h, and 24 h post-injection, respectively. The maximum ratio of MCA-tk to MCA tumor was 192.7 at 24 h. Ratios of MCA-tk tumor to liver were 13.8, 66.8, and 588.3 at 1 h, 4 h, and 24 h, respectively. On small animal PET, [$^{124}I$]FIAU accumulated in substantial higher levels in MCA-tk tumor and liver than MCA tumor. Conclusion: FIAU shows selective accumulation to HSV1-tk expressing hepatoma cell tumors with minimal uptake in normal liver. Therefore, radiolabelled FIAU is expected to be a useful substrate for non-invasive imaging of HSV1-tk gene therapy and therapeutic response monitoring of HCC.