• Journal of Periodontal and Implant Science
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• 제43권4호
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• pp.168-176
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• 2013

Purpose: The purpose of the current study was to examine the effect of dexamethasone (Dex) at various concentrations on the apoptosis and mineralization of human periodontal ligament (hPDL) cells. Methods: hPDL cells were obtained from the mid-third of premolars extracted for orthodontic reasons, and a primary culture of hPDL cells was prepared using an explant technique. Groups of cells were divided according to the concentration of Dex (0, 1, 10, 100, and 1,000 nM). A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed for evaluation of cellular viability, and alkaline phosphatase activity was examined for osteogenic differentiation of hPDL cells. Alizarin Red S staining was performed for observation of mineralization, and real-time polymerase chain reaction was performed for the evaluation of related genes. Results: Increasing the Dex concentration was found to reduce cellular viability, with an increase in alkaline phosphatase activity and mineralization. Within the range of Dex concentrations tested in this study, 100 nM of Dex was found to promote the most vigorous differentiation and mineralization of hPDL cells. Dex-induced osteogenic differentiation and mineralization was accompanied by an increase in the level of osteogenic and apoptosis-related genes and a reduction in the level of antiapoptotic genes. The decrease in hPDL cellular viability by glucocorticoid may be explained in part by the increased prevalence of cell apoptosis, as demonstrated by BAX expression and decreased expression of the antiapoptotic gene, Bcl-2. Conclusions: An increase in hPDL cell differentiation rather than cellular viability at an early stage is likely to be a key factor in glucocorticoid induced mineralization. In addition, apoptosis might play an important role in Dex-induced tissue regeneration; however, further study is needed for investigation of the precise mechanism.

• 대한기관식도과학회:학술대회논문집
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• 대한기관식도과학회 1993년도 제27차 학술대회 초록집
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• pp.85-85
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• 1993

후두 편평세포암은 종양세포의 생물학적 특성과 발생부위별 미세환경이 다르기 때문에 임상적 병기만으로 예후를 추정하는 것은 다소 문제점이 있다. 이에 저자들은 종양세포의 유전정보에 의한 증식능이 예후와 연관성이 있는지 규명하고자 EGFR, p53 단백 및 pRB의 표현양상을 후두 편평세포암 40례의 임상적 특성과 비교 검토하여 다음과 같은 성적을 얻었다. 1. p53 단백의 양성 표현율은 임상적 병기, 원발병소의 병기, 경부 림프전이절의 병기, 병리조직학적 분화도, 재발이나 원격전이 흑은 이차암이 있었던 경우와 연관성이 높았다. 2. pRB의 음성 표현율은 침습성이 강한 성문상분, 임상적 병기, 원발병소의 병기, 병리 조직학적 분화도, 재발이나 원격전이 혹은 이차암, 치료에 실패한 경우와 연관성이 높았다. 3. 3년생존율은 p53의 양성표현율과 관계가 있었다. 4. EGFR은 특별한 상관관계가 없었다. 이상의 결과로 보아 p53 단백과 pRB의 암억제유전자 단백의 면역조직화학적 염색을 통한 표현양상은 후두 편평세포암의 생물학적인 특성을 잘 반영하고 있을 뿐만 아니라 종양 즉 인자들과 밀접한 상관관계가 있어 후두 편평세포암의 악성도를 예측하는데 도움을 주는 예후인자로서 적용시킬 수 있을 것으로 생각된다.

• 생명과학회지
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• 제20권7호
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• pp.991-998
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• 2010

저산소상태(hypoxia)는 세포유형 및 성장조건에 따라 apoptosis를 유발하거나 또는 apoptosis의 진행을 억제한다. 저산소상태 유발물질인 cobalt chloride ($CoCl_2$) 역시 여러 세포 유형에서 apoptosis를 유발한다고 알려져 있으나 그 기작은 불명확하다. 본 연구에서는 PC-3 세포에서 $CoCl_2$에 의해 down-regulation되는 puromycin-sensitive aminopeptidase (PSA)의 세포 내 기능을 조사하였다. 본 연구 결과, PC-3 세포에 puromycin을 처리한 결과 전체 세포 집단의 약 42%에서 apoptosis가 유도되었다. PSA가 apoptosis에 관여하는지를 확인하고자 PSA siRNA로 내재성 PSA의 발현을 억제시킨 다음 apoptosis 연관 특성을 조사한 결과 PSA의 발현 억제에 의해 효과적으로 apoptosis가 유도되었다. 이러한 결과는 PC-3 세포에서 PSA가 세포생존에 중요한 역할을 할 것임을 보여주는 것이라 사료된다.

• Molecules and Cells
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• 제41권2호
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• pp.119-126
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• 2018

microRNA (miR)-612 shows anticancer activity in several types of cancers, yet its function in melanoma is still unclear. This study was undertaken to investigate the expression of miR-612 and its biological relevance in melanoma cell growth, invasion, and tumorigenesis. The expression and prognostic significance of miR-612 in melanoma were examined. The effects of miR-612 overexpression on cell proliferation, colony formation, tumorigenesis, and invasion were determined. Rescue experiments were conducted to identify the functional target gene(s) of miR-612. miR-612 was significantly downregulated in melanoma tissues compared to adjacent normal tissues. Low miR-612 expression was significantly associated with melanoma thickness, lymph node metastasis, and shorter overall, and disease-free survival of patients. Overexpression of miR-612 significantly decreased cell proliferation, colony formation, and invasion of SK-MEL-28 and A375 melanoma cells. In vivo tumorigenic studies confirmed that miR-612 overexpression retarded the growth of A375 xenograft tumors, which was coupled with a decline in the percentage of Ki-67-positive proliferating cells. Mechanistically, miR-612 targeted Espin in melanoma cells. Overexpression of Espin counteracted the suppressive effects of miR-612 on melanoma cell proliferation, invasion, and tumorigenesis. A significant inverse correlation (r = -0.376, P = 0.018) was observed between miR-612 and Espin protein expression in melanoma tissues. In addition, overexpression of miR-612 and knockdown of Espin significantly increased the sensitivity of melanoma cells to doxorubicin. Collectively, miR-612 suppresses the aggressive phenotype of melanoma cells through downregulation of Espin. Delivery of miR-612 may represent a novel therapeutic strategy against melanoma.

• 한국군사과학기술학회지
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• 제18권4호
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• pp.478-483
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• 2015

Decontamination of biological agents utilizes hydrogen peroxide($H_2O_2$) for its effectiveness and safeness. Bacillus anthracis is a major target for $H_2O_2$ decontamination. To assess the effect of $H_2O_2$ on B. anthracis and identify biomarkers for decontamination, whole transcriptomic profiling of $H_2O_2$-treated B. anthracis was performed. Here we identified deregulation in stress response genes, transcription factors and cellular homeostasis genes. We also found that expression of antisense RNAs increased in B. anthracis during decontamination. We postulate that B. anthracis prioritizes survival and adaptation in response to $H_2O_2$ treatment by changing its gene expression pattern.

• Genomics & Informatics
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• 제7권4호
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• pp.195-202
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• 2009

BIRC5 (Survivin) belongs to the inhibitor of apoptosis gene family. The BIRC5 protein inhibits caspases and consequently blocks apoptosis. Thus, BIRC5 contributes to the progression of cancer allowing for continued cell proliferation and survival. In this study, we identified eight sequence variants of BIRC5 through direct DNA sequencing. Among the eight single nucleotide polymorphisms (SNPs), six common variants with frequencies higher than 0.05 were selected for larger-scale genotyping (n=1,066). Results of the study did not show any association between the promoter region polymorphisms and the clearance of hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC) occurrence. This is in line with a previous study in which polymorphisms in the promoter region does not influence the function of BIRC5. Initially, we were able to detect a signal with the ＋9194A>G, which disappeared after multiple corrections but led to a change in amino acid. Similarly, we were also able to detect an association signal between two haplotypes (haplotype-2 and haplotype-5) on the onset age of HCC and/or HCC occurrence, but the signals also disappeared after multiple corrections. As a result, we concluded that there was no association between BIRC5 polymorphisms and the clearance HBV infection and/or HCC occurrence. However, our results might useful to future studies.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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• pp.1644-1652
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• 2012

Iron plays a key role in host-pathogen interactions. Microbial pathogens require iron for survival and virulence, whereas mammalian hosts sequester and withhold iron as a means of nutritional immunity. We previously identified two paralogous genes, CFT1 and CFT2, which encode homologs of a fungal iron permease, Cft1 and Cft2, respectively, in the human fungal pathogen Cryptococcus neoformans. Cft1 was shown to play a role in the high-affinity reductive iron uptake system, and was required for transferrin utilization and full virulence in mammalian hosts. However, no role of Cft2 has been suggested yet. Here, we identified the third gene, CFT3, that produces an additional fungal iron permease homolog in C. neoformans, and we also generated the cft3 mutant for functional characterization. We aimed to reveal distinct functions of Cft1, Cft2 and Cft3 by analyzing phenotypes of the mutants lacking CFT1, CFT2 and CFT3, respectively. The endogenous promoter of CFT1, CFT2 and CFT3 was replaced with the inducible GAL7 promoter in the wild-type strain or in the cft1 mutant for gain-of-function analysis. Using these strains, we were able to find that CFT2 is required for growth in low-iron conditions in the absence of CFT1 and that overexpression of CFT2 compensates for deficiency of the cft1 mutant in iron uptake and various cellular stress conditions. However, unlike CFT2, no clear phenotypic characteristic of the cft3 mutant and the strain overexpressing CFT3 was observed. Overall, our data suggested a redundant role of Cft2 in the high-affinity iron uptake and stress responses in C. neoformans.

• Journal of Microbiology
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• 제38권4호
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• pp.203-208
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• 2000

Cytomegalovirus (CMV), a beta-herpesvirus with worldwide distribution, exhibits host persistence, a distinguishing characteristic of all herpesviruses. This persistence is dependent upon restricted gene expression in infected cells as well as the ability of productively infected cells to escape from normal cell-mediated anti-viral immunosurveillance. Type I (IFN-$\alpha$/$\beta$) and type II (IFN-γ) interferons are major components of the innate defense system against viral infection. They are potent inducers of MHC class I and II antigens and of antigen processing proteins. Additionally, IFNS mediate direct antiviral effects through induction effector molecules that block viral infection and replications such as 2', 5-oligoadenylate synthetase (2, 5-OAS). IFNS function through activation of well-defined signal transduction pathways that involve phosphorylation of constituent proteins and ultimate formation of active transcription factors. Recent studies have shown that a number of diverse viruses, including CMV, EBV, HPV mumps and Ebola, are capable of inhibiting IFN-mediated signal transduction through a variety of mechanisms. As an example, CMV infection inhibits the ability of infected cells Is transcribe HLA class I and II antigens as well as the antiviral effector molecules 2, 5-OAS and MxA I. EMSA studies have shown that IFN-$\alpha$ and IFN-γ are unable to induce complete signal transduction in the presence of CMV infection, phenomena that are associated with specific decreases in JAKl and p48. Viral inhibition of IFN signal transduction represents a new mechanistic paradigm for increased viral survival, a paradigm predicting widespread consequences in the case of signal transduction factors common to multiple cytokine pathways.

• 한국식품영양과학회지
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• 제35권9호
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• pp.1121-1126
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• 2006

In the present study, the potential hepatoprotective effects of poly herbal formulation, Hepa-1000, against oxidative damages induced by t-BHP were evaluated in HepG2 cells in order to relate in vitro antioxidant activity with cytoprotective effects. The t-BHP induced considerable cell damage in HepG2 cells was shown by significant glutamic oxaloacetic transaminase (GOT) and lactate dehydrogenase (LDH) leakage, and increased lipid peroxidation. Hepa-1000-treated cells showed an increased resistance to oxidative challenge, as revealed by higher survival capacity than the one of control cells against t-BHP induced oxidative stress and hepatotoxicity. In addition, the Hepa-1000 had hepatoprotective effects lowering the activity of GOT and LDH, simultaneously. That is, it could inhibit the cell membrane damages resulting in the increased activities of GOT and LDH in the cell culture media. Furthermore, the Hepa-1000 could reduce t-BHP enhanced lipid peroxidation, which was evaluated by measuring the production of malonedialdehyde. Based on the data described above, it could be suggested that the Hepa-1000 has significant hepatoprotective effects and plays a protective role against lipid peroxidation by free radicals.

• 방사선산업학회지
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• 제6권3호
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• pp.223-229
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• 2012

In this study, we investigated the biological damage and stress responses induced by ion beam (proton beam) irradiation as a basis for the development of protective measures against space radiation. We examined the biological effects of proton beam produced by MC-50 cyclotron at KIRAMS on the cultured cells and mice. The proton beam energy used in this study was 34.9 MeV and the absorption dose rate for cells and mice were $0.509Gy\;sec^{-1}$ and $0.65Gy\;sec^{-1}$, respectively. The cell survival rates measured by plating efficiency showed the different sensitivity and dose-relationship between CHO cells and Balb/3T3 cells. HGPRT gene mutation frequency in Balb/3T3 was $15{\times}10^{-6}Gy^{-1}$, which was similar to the reported value of X-ray. When stress signaling proteins were examined in Balb/3T3 cells, $I{\kappa}B-{\alpha}$ decreased markedly whereas p53, phospho-p53, and Rb increased after proton beam irradiation, which implied that the stress signaling pathways were activated by proton beam irradiation. In addition, cellular senescence was induced in IMR-90 cells. In the experiments with C57BL/6 mouse, the immune cells (white blood cells, lymphocytes) in the peripheral blood were greatly reduced following proton beam irradiation whereas red blood cells and platelets showed relatively little change. These results can be utilized as basic data for studying the biological effects of proton beam using MC-50 cyclotron with respect to proton therapy research as well as space radiation research.