• 한국환경성돌연변이발암원학회지
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• 제23권1호
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• pp.30-34
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• 2003

Recent industrial society has human widely exposed to PAHs (polynuclear aromatic hydrocarbons) that are comming from the incomplete combustion of organic material as wider spread environmental contaminants. Biological activities of PAHs are not known although PAHs are considered as carcinogens. Our laboratory have been studied the effect of PAHs in the mouse liver hepa 1 cells. In this study, we examined the mouse liver hepa-l cells as a new bioassay system to evaluate bioactivity of PAHs. We have selected 13 PAHs to examine bioassay using cyp1a1-luciferase reporter gene expression system where cyp1a1 1.6 Kb 5flanking region DNA was cloned in front of luciferase reporter gene and this plasmid was transfected into hepa 1 cells transiently. This cells then used for the study to observe the effect of PAHs. We demonstrated that PAHs induced the CYP1A1 promoter and 7-ethoxyresolufin O-deethylase (EROD) activities in a concentration-dependant manner. Some of PAHs showed stronger stimulatory effect on CYP1 gene expression than TCDD. Acenaphthene, anthracene, fluorine, naphthalene, pyrene, phenanthrene, carbazole were weak responders to cyp1a1 promoter activity stimulation and EROD induction in hepa 1 cells and these chemicals seemed to respond less to EROD than cyp1a1 promoter activity. Benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene, and dibenzo(a,h)anthracene showed strong response to cyp1a1 promoter activity stimulation and also EROD induction in hepa 1cells. Results of dose response study suggested that four strong responding PAHs, such as benzo(a)anthracene benzo(k)fluoranthene, chrysene, and dibenzo(a, h)anthracene might be mediated through arylhydrocarbon receptor system in hepa1 cells.

• Journal of Korean Neurosurgical Society
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• 제38권5호
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• pp.366-374
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• 2005

Objective : Nitric oxide[NO] is implicated in a wide range of biological processes in tumors and is produced in glioma. To investigate the role of NO and its interaction with the tumoricidal effects of anticancer drugs, we study the antitumor activities of NO donors, with or without anticancer drugs, in human glioma cell lines. Methods : U87MG and U373MG cells were treated with the NO donors sodium nitroprusside[SNP] and S-nitroso-N-acetylpenicillamine[SNAP], alone or in combination with the anticancer drugs 1,3-bis[2-chloroethyl]-1-nitrosourea[BCNU] and cisplatin. Cell viability, cell proliferation, DNA fragmentation, nitrite level, and the expression of Bcl-2 and Bax were determined. Results : NO was markedly increased after treatment with SNP or SNAP; however, the addition of the anticancer drugs did not significantly affect NO production NO donors or anticancer drugs reduced glioma cell viability and, in combination, acted synergistically to further decrease cell viability in a dose- and time-dependent manner. Cell proliferation was inhibited and apoptosis were enhanced by combined treatment. Bax expression was increased by combined treatment, whereas Bcl-2 expression was reduced. The antitumor cytotoxicity of NO donors and anticancer drugs differed according to cell type. Conclusion : BCNU or cisplatin can inhibit cell viability and proliferation of glioma cells and can induce apoptosis. These effects are further enhanced by the addition of a NO donor which modulates the antitumor cytotoxicity of chemotherapy depending on cell type. Further biological, chemical, and toxicological studies of NO are required to clarify its mechanism of action in glioma.

• Biomolecules & Therapeutics
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• 제26권4호
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• pp.399-408
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• 2018

In this study, we examined the molecular and functional characterization of choline uptake in the human esophageal cancer cells. In addition, we examined the influence of various drugs on the transport of [$^3H$]choline, and explored the possible correlation between the inhibition of choline uptake and apoptotic cell death. We found that both choline transporter-like protein 1 (CTL1) and CTL2 mRNAs and proteins were highly expressed in esophageal cancer cell lines (KYSE series). CTL1 and CTL2 were located in the plasma membrane and mitochondria, respectively. Choline uptake was saturable and mediated by a single transport system, which is both $Na^+$-independent and pH-dependent. Choline uptake and cell viability were inhibited by various cationic drugs. Furthermore, a correlation analysis of the potencies of 47 drugs for the inhibition of choline uptake and cell viability showed a strong correlation. Choline uptake inhibitors and choline deficiency each inhibited cell viability and increased caspase-3/7 activity. We conclude that extracellular choline is mainly transported via a CTL1. The functional inhibition of CTL1 by cationic drugs could promote apoptotic cell death. Furthermore, CTL2 may be involved in choline uptake in mitochondria, which is the rate-limiting step in S-adenosylmethionine (SAM) synthesis and DNA methylation. Identification of this CTL1- and CTL2-mediated choline transport system provides a potential new target for esophageal cancer therapy.

• Toxicological Research
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• 제23권2호
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• pp.135-142
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• 2007

Formononetin is an isoflavonoid phytoestrogen found in certain foodstuffs such as soy and red clover. In this study, we examined the action of formononetin with the carcinogen activation pathway mediated through the aryl hydrocarbon receptor (AhR) in MCF-7 breast carcinoma cells. Treating the cells with formononetin alone caused the accumulation of CYP1A1 mRNA as well as elevation in CYP1A1-specific 7-ethoxyresorufin O-deethylase (EROD) activity in a dose dependent manner. However, a concomitant treatment with 7,12-dimethylbenz[a]anthracene (DMBA) and formononetin markedly reduced both the DMBA-inducible EROD activity and CYP1A1 mRNA level. Under the same conditions, formononetin inhibited the DMBA-induced AhR transactivation, as shown by reporter gene analysis using a xenobiotic responsive element (XRE). Additionally, formononetin inhibited both DMBA-inducible nuclear localization of the aryl hydrocarbon receptor (AhR) and metabolic activation of DMBA, as measured by the formation of the DMBA-DNA adducts. Furthermore, formononetin competed with the prototypical AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), for binding to the AhR in an isolated rat cytosol. These results suggest that formononetin might be considered as a natural ligand to bind on AhR and consequently produces a potent protective effect against DMBA-induced genotoxicity. Therefore, that's the potential to act as a chemopreventive agent that is related to its effect on AhR pathway as antagonist/agonist.

• Journal of Microbiology and Biotechnology
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• 제13권6호
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• pp.897-905
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• 2003

Phospholipase D (PLD) and ADP-ribosylation factor (ARF) were partially purified on a series of column chromatography, and their biochemical properties were characterized to understand the regulatory mechanism of PLD activation by ARF protein in the antigen-induced immune responses in guinea pigs. Heparin Sepharose and high-Q Sepharose column chromatographies were used for the purification of PLD, and Sephadex G-25, DEAE Sephacel, Source 15 PHE (HIC), Superdex-75, and Uno-Q column chromatographies were used for the purification of ARF. The purified PLD and ARF proteins were identified with anti-rabbit PLD- or ARF-specific antibodies, showing about 64 or 85 kDa for the molecular mass of PLD and 29 or 35 kDa for the sizes of ARF. Partial cDNA of ARF3 was cloned by RT-PCR in guinea pig lung tissue and its nucleotides and amino acids were sequenced. Guinea pig ARF3 showed 92% of nucleotides sequence identity and 100% of amino acid sequence homology with human ARF3. The ARF-regulated PLD activity was measured in the oleate or ARFs-containing mixed lipid vesicles. The purified and recombinant ARF (rARF) activities were assessed with the $GTP{\gamma}S$ binding assay. The PLD activity was induced by oleate in a dose-dependent manner. The purified ARF and recombinant ARF3 increased PLD activity in guinea pig lung tissues. These data show that the activity of membrane-bound PLD can be regulated by the cytosolic ARF proteins, suggesting that ARF proteins in guinea pig lung can act as a regulatory factor in controlling the PLD activity in allergic reaction.

• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.287-294
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• 2014

The transcription factor E2F1 is active during G1 to S transition and is involved in the cell cycle and progression. A recent study reported that increased E2F1 is associated with DNA damage and tumor development in several tissues using transgenic models. Here, we show that E2F1 expression is regulated by tristetraprolin (TTP) in prostate cancer. Overexpression of TTP decreased the stability of E2F1 mRNA and the expression level of E2F1. In contrast, inhibition of TTP using siRNA increased the E2F1 expression. E2F1 mRNA contains three AREs within the 3'UTR, and TTP destabilized a luciferase mRNA that contained the E2F1 mRNA 3'UTR. Analyses of point mutants of the E2F1 mRNA 3'UTR demonstrated that ARE2 was mostly responsible for the TTP-mediated destabilization of E2F1 mRNA. RNA EMSA revealed that TTP binds directly to the E2F1 mRNA 3'UTR of ARE2. Moreover, treatment with siRNA against TTP increased the proliferation of PC3 human prostate cancer cells. Taken together, these results demonstrate that E2F1 mRNA is a physiological target of TTP and suggests that TTP controls proliferation as well as migration and invasion through the regulation of E2F1 mRNA stability.

• Environmental Analysis Health and Toxicology
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• 제20권4호통권51호
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• pp.287-296
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• 2005

아연은 다양한 독성 물질로부터 유도된 아폼토시스를 저해하는 것으로 알려져 있으나 이 기전에 대해서는 명확히 밝혀지지 않았다. 본 연구에서는 인간 유방암 세포 MCF-7에 카드뮴을 처리하였을 때 유도되는 아폼토시스에 대한 아연의 저해효과를 살펴보았다. 아연의 아폼토시스 저해 효과는 DNA분절현상, 핵의 쪼개짐 그리고 caspase-9의 발현을 통하여 확인하였다. 또한 아연의 아폼토시스 저해효과가 카드뮴에 의한 산화적 스트레스와 관련이 있는지 확인하기 위하여 활성산소인 peroxide의 농도를 세포내에서 측정하였다. 나아가 superoxide dismutase (SOD), catalase (CAT) 그리고 glutahion redurtase (CR)같은 활성산소에 대한 인체내 방어기작으로 작용하는 항산화 효소의 활성을 측정하였다. 본 연구를 통해 아연이 카드뮴에 의해 생성된 세포내의 활성산소의 양을 감소시키고 항산화 효소를 회복시키는 기전이 카드뮴에 의한 아폼토시스를 저해하는 한 요인으로 사료되어진다.

• Environmental Analysis Health and Toxicology
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• 제20권4호통권51호
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• pp.365-374
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• 2005

Ambient air particulate matters are classified into two distinct modes in sire distribution, namely the coarse and fine particles. Correlation between high particulate concentration and adverse effect on human populations has long been recognized. However, the toxicology of these adverse efforts has not been clarified. We investigated the genotoxic effect of PM 2.5 collected from urban area in Seoul by comet assay (A549 cells), CBMN assay (CHO-K1 cells) and EROD-microbioassay (H4IIE cells). Results from in vitro micronucleus assay and comet assay showed that PM 2.5 samples collected from traffic area, residential area and indoor air induced chromosomal damage and DNA breakage in a non-cytotoxic dose. The complex mixture effect of these PM 2.5 extracts was quantified by EROD-microbioassay in terms of its bio-TEQ (biologiral -TCDD equivalent concentration) which was 70.87$\pm$28.07, 93.55$\pm$21.80 and 14.31 $\pm$ 1.10 ng/g-PM 2.5 in traffic area, residental area and indoor air samples, respectively. Conclusively, we suggested that PM 2.5 collected from traffic area and residential area contains CYPIA inducer and genotoxic materials.

• Journal of Dairy Science and Biotechnology
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• 제24권1호
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• pp.19-28
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• 2006

유아 분변으로부터 분리한 52 균주는 그람 양성균인 Listeria monocytogenes KCCM 40307$^T$에 대하여 항균활성이 있었고 그 중에서도 선별 균주 A24의 항균활성이 45% 이상으로 가장 높았다. Bifidobacterium longum A24의 생육 및 항균 물질 생산을 검토하였을 때 균체의 생육은 28시간 배양 시 최고에 도달하였고 항균 활성은 36시 간 배양 시 최고를 나타내었다. 선별균주 A24는 16S rRNA-based molecular typing 결과Bifidobacterium 속 균주임을 확인할 수 있었고 형태학적 ${\cdot}$ 생화학적인 방법으로 검토하여 보았을 때 Bifidobacterium longum으로 판단되었으며, 16s rDNA sequencing 결과 최종적으로 Bifidobacterium longum로 동정 되었으며 이것을 Bifidobacterium longum A24로 명명하였다. Bifidobacterium longum A24의 항균 활성 물질은 균체의 생육이 가장 좋은 28시간 배양에서가 아니라 그보다 늦은 36시간 배양에서 최고를 나타내었고 그 이후로는 활성이 감소하는 경향을 보였다. 이것은 Bifidobacterium longum A24이 생성하는 항균 활성 물질이 bacteriocin과 같은 2차 대사 산물임을 암시하는 결과로 해석된다.

• 대한미생물학회지
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• 제17권1호
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• pp.7-14
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• 1982

A model of induction of neoplasia by viruses has develpoed from experimental studies in animals and in cultured cells and oncogenic transformation of cells is the result of integration of viral genetic information into the cellular DNA. The evidence for these associations was derived primarily from seroepidemiologic investigation. However, data indicating that the relation between HSV-2 and cervical cancer fits the model derived from experimental animal studies are not yet sufficient to draw conclusion with regard to the etiologic role the virus in the development of the neoplasms. In other hand, the K562 tumor cell is highly susceptible target for natural killer cell lysis by the lymphocytes of human and murine periperal blood. The characteristics of this effector cell type has been investigated. A study on natural killer cell mediated cytotoxicity(NKMC) against $^{51}Cr$-K562 as target cell was studed in HSV-2 infected ICR mouse. We have studied for susceptibility of HSV-2 against mouse embryo fibroblast(MEF) cells and NKMC from HSV-2 infected mouse. The results obtained that the mouse embryo fibroblast cells culture, the number and size of the cells were markedly increased and formed a monolayers relatively rapid, and become complete monolayer sheet around 72 hrs. Duration of cytopathic effect on MEF cells was rapid by serial passing of HSV-2. The morphology of the HSV-2 infected cells appear to be mainly round, ovium, spindle form and some of them was forming large giant cells. The NKMC was decrease in mouse with HSV-2 and comparison between effector/target cells ratio as 25:1 and 50:1 respectively, the NKMC was found to be more significantly decreased than normal control we have concluded that the natural killer cell activity of the viral infected mouse was shown as a suppressed during the HSV-2 infection, day 7th and 14th.