• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
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• pp.139-139
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• 1998

Effects of TCDD and flavonoids on ethoxyresorufin deethylase in Hepa I cells and MCF-7 human breast cancer cells were examined. TCDD treatment have resulted in the stimulation of ethoxyresorufin deethylase activity based on fluorometry in Hepa I in dose and time dependent manner. 0.1 nM TCDD showed maximal stimulation of ethoxyresorufin deethylase activity and 24 hour treatment also showed maximal stimulation of ethoxyresorufin deethylase activity. In MCF-7 human breast cancer cells, untreated cells showed high basal level of ethoxyresorufin deethylase activity. TCDD treatment to MCF-7 cells resulted minor stimulation of ethoxyresorufin deethylase activity compared to that in Hepa I cells. Various chemicals were tested for ethoxyresorufin deethylase activity in both cell lines. Flavonoids, such as quercetin showed an inhibition of ethoxyresorufin deethylase activity that is stimulated with TCDD or 3-Methylcholanthrene. Estrogen and estrogen metabolites such as 16a-estriol also affects the ethoxyresorufin deethylase activity in MCF-7 cells.

• International Journal of Oral Biology
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• 제48권1호
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• pp.1-7
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• 2023

Oral squamous cell carcinoma (OSCC), which accounts for approximately 90% of oral cancers, has a high rate of local recurrence and a poor prognosis despite improvements in treatment. Exosomes released from OSCC cells promote cell proliferation and metastasis. Although it is clear that the biogenesis of exosomes is mediated by the endosomal sorting complex required for transport (ESCRT) machinery, the gene expression pattern of ESCRT, depending on the cell type, remains elusive. The exosomal release from the human OSCC cell lines, HSC-3 and HSC-4, and their corresponding gefitinib-resistant sub-cell lines, HSC-3/GR and HSC-4/GR, was assessed by western blot and flow cytometry. The levels of ESCRT machinery proteins, including Hrs, Tsg101, and Alix, and whole-cell ubiquitination were evaluated by western blot. We observed that the basal level of exosomal release was higher in HSC-3/GR and HSC-4/GR cells than in HSC-3 and HSC-4 cells, respectively. Long-term gefitinib exposure of each cell line and its corresponding gefitinib-resistant sub-cell line differentially induced the expression of the ESCRT machinery. Furthermore, whole-cell ubiquitination and autophagic flux were shown to be increased in gefitinib-treated HSC-3 and HSC-4 cells. Our data indicate that the expression patterns of the ESCRT machinery genes are differentially regulated by the characteristics of cells, such as intracellular energy metabolism. Therefore, the expression patterns of the ESCRT machinery should be considered as a key factor to improve the treatment strategy for OSCC.

• 대한약리학회지
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• 제32권3호
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• pp.335-345
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• 1996

허혈/재관류 뇌손상에서 활성산소류의 역할이 중요시되고 있다. 본 연구에서는 모래쥐의 총경동맥을 묶었다 풀어줌으로써 실험적 허혈/재관류 손상을 유도하고 산화성 스트레스 발생 유무와 이러한 산화성 스트레스가 세포손상으로 연결되는지를 알아보고자 하였다. 해마는 뇌조직 중에서도 특히 산화성 스트레스에 취약한 부분이므로 해마에서 얻은 조직을 대뇌피질에서 얻은 조직과 비교분석하였다. 또한, 이들 부위에서 heat shock protein 70(HSP70)의 발현이 허혈/재관류 손상에 미치는 영향도 검색하고자 하였다. 허혈/재관류에 의한 산화성 스트레스의 지표로써 글루타치온 산화정도, GSSG/(GSH+2xGSSG)를 측정하였을 때 주로 해마에서 산화지표가 상승됨을 관찰하였다. 한편 산화성 스트레스가 세포손상으로 연결되는지를 알아보고자 지질과산화물을 측정하였다. 두 부위 모두에서 지질과산화물 형성의 증가가 있었으며 대뇌피질에서보다 해마에서 더 증가됨을 알 수 있었다. 지질과산화물 형성의 정도나 시간적 변화양상이 글루타치온 산화의 그것들과 유사하였다. 이러한 결과들은 허혈/재관류에 의해 산화성 스트레스가 형성되며 동시에 이러한 산화성 스트레스가 세포 손상을 초래함을 보여준다. 또한 산화성 스트레스 및 산화성 세포손상 정도가 대뇌피질보다는 해마에서 더 큰 것을 알 수 있었다. 그러나, 피질과 해마에서 HSP70의 기초발현(basal level) 정도는 차이가 없었다. 이는 해마의 취약성이 HSP70 발현 결핍에 기인하지 않았음을 나타낸다. 반면 허혈/재관류에 의한 HSP70의 발현유도는 해마조직에서 제대로 이주어지지 않았고 northern blot결과 이는 전사단계에서의 부친에 의한 것으로 나타났다. 이러한 결과들로 볼 때 허혈/재관류에 의한 뇌손상에서 HSP70 유도정도를 측정하는 것이 세포의 취약성을 예측할 수 있는 지표로 유용하게 사용될 수 있을 것으로 사료된다.

• 식물조직배양학회지
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• 제24권1호
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• pp.1-35
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• 1997

Fertilized egg, by successive cell divisions, differentiates into different tissues and organs with various structures and functions. Different cells and tissues contain different proteins, products of selective gene expression. Not all the genes in any genomes are equally active, temporal and spatial gene expression being the general rule. Present paper attempts to review the tanscriptional mechanisms or the initiations of transcription from several angles. In some of the organisms the genes in the process of transcription or the genes in the inactive state can be seen under the light microscope. Some bands of Drosophila polytene chromosomes may exhibit a swollen or puff appearance under certain conditions. A puff, unfolded or decondensed form of chromomere, represents sets of intense transcriptional activity or RNA synthesis. The heterochromatic X chromosome whose genes remain inactive in the female mammals can be visualized as a dark staining structure called Barr body, Configuration of chromatin differs between transcribed and nontranscribed chromatin. Modification to the chromatin facilitates RNA synthesis. The movement of large polymerase molecule along the DNA would probably be facilitated if some modifications of the chromatin configuration is effected. Methylation of cytosines in CG sequences is associated with inactive genes. Methylation can play a role in determination of mammalian cells during embryogenesis. Demethylation is necessary for the gene to be expressed during development A histone modification that is also known to be correlated with transcriptional capacity of chromatin is acetylation of the lysine residues of the core histones. Chromatin containing a high level of histone acetylation is very sensitive to DNase 1. For the transcription to occur TBP must first bind to the TATA box. Another TF, TF IIB, then binds to the promoter-TBP complex, facilitating the access of RNA polymerase to the transcription initiation site. As recently as eight years ago researchers assumed that histones were irrelevant to the regulation of gene expression. Histones combine with the DNA to form nucleosome of the chromatin. Histones are vital participant in gene regulation. Histone and basal factors compete for access to TATA box. When DNA is exposed to basal factors before histones are introduced, the basal factors assemble on TATA boxes preventing the access of histones, allowing transcription to occur, for transcription to begin, activator protein at the upstream activation sequence or enhancer must interact with the tail of histone H4 at TATA box and cause the histone role particle to dissociate from the TATA box leading to partial breakup of the histone core particle and allowing the basal factors to bind to the TATA box. New concept of genomic flux in contrast to the old concept of static genome has been developed based on the powerful new molecular techniques. Genomic changes such as repetitive DNAs and transposable elements, it is assumed but not yet proved, may affect some of the developmental patterns that characterize particular cells, tissues, organs, and organisms. In the last decade or so remarkable achievement have been made in the researches of the structures and functions of TFs and the specific target sequences located in promoters or enhancers where these TFs bind. TFs have independent domains that bind DNA and that activate transcription. DNA binding domain of TFs serves to bring the protein into the right location. There are many types of DNA binding domains. Common types of motifs can be found that are responsible for binding to DNA. The motifs are usually quite short and comprise only a small part of the protein structure. Steroid receptors have domains for hormone binding, DNA binding, and activating transcription. The zinc finger motif comprises a DNA binding domain. Leucine zipper consist of a stretch of amino acids with a leucine residue in every seventh position Two proteins form a dimer because they interact by means of leucine zippers on similar α-helical domain. This positions their DNA binding basic domains for interaction with the two halves of a DNA sequence with dyad symmetry of TGACTCA, ACTGAGT.

• Journal of Microbiology and Biotechnology
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• 제8권1호
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• pp.14-20
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• 1998

Syntheses of the B. stearothermophilus xylanolytic enzymes such as xylanases, ${\beta}$-xylosidases, ${\alpha}$-arabinofurano-sidases, and esterases, were observed to be regulated by the carbon source present in the culture media. Xylan induced synthesis of ${\beta}$-xylosidase at the highest level while xylose gave about 30% of the ${\beta}$-xylosidase activity induced by xylan. The lowest syntheses of the xylanolytic enzymes above mentioned were detected in the basal medium containing glucose as a sole carbon source. When a mixture of xylan and glucose was used as a carbon source, we could observe glucose repression of xylanase (about 70-fold) and ${\beta}$-xylosidase (about 40-fold) syntheses. Whereas, the level of the glucose repression of the expression of the xylA gene encoding the major ${\beta}$-xylosidase of B. stearothermophilus was assessed to be about l0-fold when the relative amounts of the xylA transcript were determined. From the sequence of the xylA gene, we could find two CRE-like sequences (CRE-l: nucleotides ＋124 to ＋136 and CRE-2:＋247 to ＋259) within the reading frame of the xylA gene, either or both of which were suspected to be involved in catabolite repression of the xylA gene.

• The Korean Journal of Physiology and Pharmacology
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• 제16권5호
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• pp.305-312
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• 2012

This study was to determine the effect of exercise on the recovery of dopaminergic neuron loss and muscle atrophy in 6-OHDA-induced hemi Parkinson's disease model. Exercise was loaded twice per day for 30 minutes each time, at 5 days after 6-OHDA lesioning and continued for 16 days using a treadmill. Exercise significantly increased the number of tyrosine hydroxylase positive neuron in the lesioned substantia nigra and the expression level of tyrosine hydroxylase in the striatum compared with the control group. To examine which signaling pathways may be involved in the exercise, the phosphorylation of $GSK3{\beta}$ and ERK were observed in the striatum. In the control group, basal level of $GSK3{\beta}$ phosphorylation was less than in both striatum, but exercise increased it. ERK phosphorylation decreased in the lesioned striatum, but exercise recovered it. These findings suggest that exercise inactivates $GSK3{\beta}$ by phosphorylation which may be involved in the neuroprotective effect of exercise on the 6-OHDA-induced cell death. In the exercise group, weight, and Type I and II fiber cross-sectional area of the contralateral soleus significantly recovered and expression of myosin heavy chain and Akt and ERK phosphorylation significantly increased by exercise. These results suggest that exercise recovers Parkinson's disease induced dopaminergic neuron loss and contralateral soleus muscle atrophy.

• Journal of Plant Biotechnology
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• 제7권2호
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• pp.97-103
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• 2005

This study was carried out to obtain basic information for gene manipulation in potent edible tobacco (Nicotiana tabacum cv. TI 516). N. tabacum cv. TI 516 is a plant for a possible candidate to use as an edible vaccine, since it contains a low level of nicotine. The effective plant regeneration system through leaf disc culture was achieved using a MS basal medium supplemented with 0.1 mg $1^{-1}$ NAA and 0.5 mg $1^{-1}$ BA. In order to transform the N. tabacum cv. TI 516 with the green fluorescent protein (GFP) gene, Agrobacterium tumefaciens LBA 4404 containing the GFP gene was used. Genomic PCR confirmed the integration of the GFP gene into nuclear genome of transgenic plants. Expression of the GFP gene was identified in callus, apical meristem and root tissue of transgenic N. tabacum cv. TI 516 plants using fluorescence microscopy. Western blot analysis revealed the expression of GFP protein in the transgenic edible tobacco plants. The amount of GFP protein detected in the transgenic tobacco plants was approximately 0.16% of the total soluble plant protein (TSP), which was determined by ELISA.

• Fisheries and Aquatic Sciences
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• 제14권2호
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• pp.93-104
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• 2011

Two hepcidin paralogs (ojhamp1 and ojhamp2) were isolated and characterized from a euryhaline Javanese ricefish (Oryzias javanicus: Beloniformes). The ojhamp1 cDNA encoded 90 or 91 amino acids (aa) of a typical HAMP1 preproprotein. This preproprotein is believed to cleave and yield the 66 or 67 aa-proprotein, followed by the 26 aa-mature peptide, composed of 8 conserved cysteine residues and the QSHL amino terminal motif. The ojhamp2 cDNA encoded 89 aa of HAMP2 preproprotein, cleaved to yield a 65 aa proprotein, and subsequently the 25 aa-mature peptide. The mature OJHAMP1 possessed a cationic isoelectric point (pI), whereas OJHAMP2 had an anionic charge. At the genomic level, both ojhamp1 and ojhamp2 share a conserved tripartite structure (three exons interrupted by two introns) with other vertebrate hepcidin genes. However, the ojhamp1 was shown to exist as two distinct mRNA species, encoding 90 or 91 aa, due to alternative splicing at the junction site between intron I and exon II. Both ojhamp1 and ojhamp2 transcripts were detected in a wide range of tissue types with varying levels of basal expression, although the highest expression was observed in the liver for both isoforms. Transcriptional response to bacterial challenge using Edwardsiella tarda showed that ojhamp1 was moderately upregulated in the liver but remained unchanged in the kidney. However, the ojhamp2 was significantly suppressed in both the kidney and liver, suggesting a potential diversification between the two paralogs.

• Molecular & Cellular Toxicology
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• 제5권2호
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• pp.133-140
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• 2009

Caveolin may be a molecular target for modulation of aging process in cochlear hair cells and have association with oxotoxicity. First we investigated the basal expression of caveolin-1, caveolin-2, caveolin-3, nitric oxide synthase, and superoxide dismutase in UB/OC-1 cochlear hair cell line. By using a RNA interference technique, we investigated whether down-regulation of caveolin influenced telomerase activity and reactive oxygen species (ROS) production in cochlear hair cells. In addition, cisplatin and gentamycin, known ototoxic drugs, were administered to the cochlear cells to determine their impact on caveolin expression. Further attempts at elucidating cellular aging mechanism with caveolin and ototoxic drugs were carried out. The main discoveries were the presence of caveolin-1 in UB/OC-1 cells and that down-regulation of caveolin-1 reduced protein kinase A activity. Telomerase was activated by caveolin down-regulation and caveolin down-regulation inhibited oxidative stress at the mitochondrial level. When cisplatin and gentamycin were administered to the cochlear hair cells during a caveolin expression state, a decrease in telomerase activity and increase ROS activity was observed. Caveolin-1 may modulate the senescent mechanisms in cochlear cells. An increase in caveolin-1 levels can lead to ROS production in the mitochondria which may cause ototoxicity.

• Biomolecules & Therapeutics
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• 제21권1호
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• pp.49-53
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• 2013

A number of naturally-occurring or synthetic chemicals have been reported to exhibit prostate chemopreventive effects. Synthetic $5{\alpha}$-reductase (5-AR) inhibitors, e.g. finasteride and durasteride, gained special interests as possible prostate chemopreventive agents. Indeed, two large-scale epidemiological studies have demonstrated that finasteride or durasteride significantly reduced the incidence of prostate cancer formation in men. However, these studies have raised an unexpected concern; finasteride and durasteride increased the occurrence of aggressive prostate tumor formation. In the present study, we have observed that treatment of finasteride did not affect the growth of androgen-refractory PC-3 prostate cancer cells. Finasteride also failed to induce apoptosis or affect the expression of proto-oncogenes in PC-3 cells. Interestingly, we found that treatment of finasteride induced the expression of Nrf2 and HO-1 proteins in PC-3 cells. In particular, basal level of Nrf2 protein was higher in androgen-refractory prostate cancer cells, e.g. DU-145 and PC-3 cells, compared with androgen-responsive prostate cancer cells, e.g. LNCaP cells. Also, treatment of finasteride resulted in a selective induction of Nrf2 protein in DU-145 and PC-3 cells, but not in LNCaP cells. In view of the fact that upregulation of Nrf2-mediated phase II cytoprotective enzymes contribute to attenuating tumor promotion in normal cells, but, on the other hand, confers a selective advantage for cancer cells to proliferate and survive against chemical carcinogenesis and other forms of toxicity, we propose that finasteride-mediated induction of Nrf2 protein might be responsible, at least in part, for an increased risk of high-grade prostate tumor formation in men.