• Journal of Life Science
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• v.17 no.8 s.88
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• pp.1053-1062
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• 2007

In the present work, we show that tamoxifen(Tam)-induced cytotoxicity is due to the mitochondrial-dependent pathway triggered by the intracellular $Ca^{2+}$ increase in MCF-7 human breast cancer cells. Tam induced the intracellular $Ca^{2+}$ increase. According to the experimental results with $Ca^{2+}$ channel blockers, Tam-induced $Ca^{2+}$ uptake seemed to depend on the voltage-sensitive $Ca^{2+}$ channel at the early stage, but at later stages the intracellular $Ca^{2+}$ increases are more likely due partly to the release of stored $Ca^{2+}$ and partly to the capacitative $Ca^{2+}$ or other entry pathways. Tam-induced $Ca^{2+}$ increase led to the release of cytochrome c from mitochondria into the cytosol and the change of mitochondrial membrane potential. In MCF-7 cells, caspase-7 plays a key role in the downstream of apoptosis because caspase-3 is absent. In the cells treated with Tam, caspase-7 cleavage was increased almost two-fold. There was no marked alteration in the level of anti-apoptotic Bcl-2 protein; however, the cells showed increased expression of pro-apoptotic Bax protein more than two-fold in response to Tam. These results imply that the apoptotic signaling pathway activated by Tam is likely to be mediated via the mitochondrial-dependent pathway.

• Journal of Applied Biological Chemistry
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• v.63 no.1
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• pp.95-101
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• 2020

Psoriasis is an autoimmune skin disease that is accompanied by hyper proliferation of the epidermis, erythema of various sizes, and ulceration. However, the mechanism of the development of psoriasis dermatitis is unclear. Recently, it is known that the inflammatory cytokines and Th17 cells as well as chemokine (CC motif) ligand 20 (CCL20) are involved in the process of keratinocytes hyper-differentiation, which is common in psoriasis dermatitis. Therefore, we studied the effects of yakuchinone-A, an active ingredient of Alpinia oxyphylla Miquel known for its anti-inflammatory activity, to improve psoriasis dermatitis. First, cytotoxicity of yakuchinone-A was observed in cell counting kit-8 assay and not observed in 10 ㎍/mL concentration on the human keratinocyte HaCaT cells. Yakuchinone-A in the presence of tumor necrosis factor-alpha (TNF-α) on HaCaT cells inhibited mRNA expression of IL-6, IL-8, and TNF-α by up to 61.4±7.5, 23.6±1.5, 46.0±4.8%. CCL20, a chemokine that attracts immune cells such Th17 cells to the inflammation location, was also significantly suppressed by yakuchinone-A. In addition, IκB and STAT3 phosphorylation involved in the CCL20 expression was inhibited by yakuchinone-A in a concentration-dependent manner up to the level of 79.1±5.0, 80.8±2.3%. Furthermore, yakuchinone-A downregulated CCL20 mRNA expression level on IL-17A-activated HaCaT cells as a concentration-dependent manner. Based on these results, yakuchinone-A is expected to be developed as a new material for improving psoriasis dermatitis in the future.

• Journal of Life Science
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• v.29 no.10
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• pp.1104-1110
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• 2019

Recently, there has been an increase in the elderly population of the world. Consequently, bone metabolic diseases such as osteoporosis are emerging as a social problem. Osteoclasts play a role in bone resorption, and osteoporosis is induced when bone resorption occurs excessively. Because currently used bone resorption inhibitors may cause side effects when used for a long period of time, it is necessary to develop a new material that effectively inhibits osteoclast differentiation. This study aimed to confirm the inhibitory effect of ethanol extract of Locusta migratoria on RANKL-induced osteoclast differentiation and its mechanism. The toxicity and proliferation effects of LME on RAW264.7 osteoclasts were measured by an MTS assay. There was no cytotoxicity or proliferation when the osteoclasts were treated with up to $2,000{\mu}g/ml$ of LME. In order to confirm the effect of LME on the differentiation of osteoclasts, osteoclasts were treated with RANKL alone or with LME for 3 days. As a result of a TRAP (tartrate-resistant acid phosphatase) assay, the increasing osteoclast differentiation by RANKL decreased in a concentration-dependent manner with the treatment of LME. In addition, LME suppressed the expression of differentiation-related marker genes (TRAP, RANK, NFATc1, and CK) and proteins (NFATc1 and c-Src) that had been increased by RANKL. Also, LME influenced the $NF-{\kappa}B$, ERK and JNK signaling pathways, resulting in the inhibition of osteoclast differentiation. These results suggest that LME may be used as a novel functional material for the prevention and treatment of osteoporosis by playing a role in inhibiting bone absorption.

• Journal of Life Science
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• v.22 no.1
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• pp.16-24
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• 2012

Polyamines are essential for cell growth and differentiation; however their precise roles are unclear yet. In the present study, the cytotoxic effect of spermine (spm) on MCF-7 cells was investigated. In the MTT assay of MCF-7 cells treated with spm, cell viability was significantly decreased in a time-and dose-dependent manner. Cell viability measurement was confirmed by trypan blue staining. FACS analysis shows that sub-G1 was increased in a time-and dose-dependent manner too. When the cells were treated with spm, cells started to show morphological changes within 2 hrs. The expression of adhesion proteins (FAK and integrin ${\beta}1$), and cytoskeletal protein (actin) was checked by Western blotting analysis. Integrin ${\beta}1$ levels were slightly decreased, and FAK and actin levels were rapidly decreased with spm treatment. In confocal laser scanning microscopy, the distribution of actin did not change but the expression decreased in a dose-dependent manner with spm treatment. FAK was evenly distributed under the plasma membrane in the untreated control. However, at 10 ${\mu}M$ spm FAK seemed to move toward the cell nucleus. Integrin ${\beta}1$, which was mainly found in the focal point of the plasma membrane in the untreated control, dispersed through the entire plasma membrane in spm treatment. The present results indicate that cytotoxic effects of spm are triggered by the disruption of adhesion proteins and cytoskeletal protein.

• Journal of Life Science
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• v.30 no.11
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• pp.983-989
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• 2020

The balance between bone-resorbing osteoclasts and bone-forming osteoblasts is key to bone health. An imbalance between osteoclasts and osteoblasts leads to various bone-related disorders, such as osteoporosis, osteomalacia, and osteopetrosis. However, the bone-resorption inhibitor drugs that are currently used may cause side effects. Natural substances have recently received much attention as therapeutic drugs for the treatment of bone health. This study was designed to determine the effect of Tenebrio molitor larvae ethanol extract (TME) on receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation. To measure the effect of TME on osteoclast differentiation, RAW264.7 cells were treated with RANKL with or without TME for 5 days. The tartrate-resistant acid phosphatase (TRAP) activity was significantly inhibited by treatment of TME without cytotoxicity up to 2 mg/ml. In addition, TME effectively suppressed expression of osteoclast differentiation-related marker genes and proteins such as TRAP, NFATc1, and c-Src. TME also significantly inhibited the p38 mitogen-activated protein kinase (MAPK) signaling pathway without affecting ERK and JNK signaling in RANKL-induced RAW264.7 cells. Consequently, we conclude that TME suppresses osteoclast differentiation by inhibiting RANKL-induced osteoclastogenic genes expression through the p38 MAPK signaling pathways. These results suggest that TME and its bioactive components are potential therapeutics for bone-related diseases such as osteoporosis.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.648-655
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• 2010

This study is the first comprehensive report on the molecular cloning, structural characterization, sequence comparison between wild and mutant types, copy number in the genome, expression features and activities of a gene encoding 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in Korean lawn grass ($Zoysia$ $japonica$). The full length cDNA of the EPSPS from Korean lawn grass ($zj$EPSPS) obtained from a 3' and 5' RACE method was 1540 bp, containing a 1176 bp ORF, a 144 bp leader sequence (5' UTR) and a 220 bp 3' UTR, which was eventually decoded 391 amino acid residues with a molecular mass of 41.74 kDa. The Southern blot detection of the $zj$EPSPS showed that the gene exists as a single copy in the Korean lawn grass genome. Sequence comparison of the $zj$EPSPS gene demonstrated that the glyphosate-tolerant mutant (GT) having a Pro-53 to Ser substitution in the gene seems to have a preferred binding activity of the enzyme to phosphoenol pyruvate(PEP) over glyphosate, which allows the continuous synthesis of aromatic amino acids in the shikimate pathway. From the Northern blotting analysis, the $zj$EPSPS was found to be highly expressed, with continuous increase until 36 hours after 0.5% glyphosate treatment in both wild and mutant samples, but 1.5-fold higher EPSP synthase activity was observed in the tolerant mutant when exposed to the glyphosate treatment. The molecular information of the $zj$EPSPS gene obtained from this study needs to be further dissected to be more effectively applied to the development of gene-specific DNA markers and zoysiagrass cultivars; nevertheless, the glyphosate-tolerant mutant having the featured $zj$EPSPS gene can be provided to turfgrass managers for weed problems with timely adoptable management options.

• Journal of Applied Biological Chemistry
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• v.60 no.4
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• pp.363-372
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• 2017

Hypericum ascyron has long been used as medicinal plant and recent studies reported that H. ascyron has anti-diabetic, anti-oxidant, and anti-bacterial effects. In this study, inhibitory effect from H. ascyron on pro-inflammatory responses has been investigated. H. ascyron was extracted at optimal extraction condition. Total phenolic contents in water and 90% ethanol were 29.75 and 31.82 mg/g, respectively. Hyaluronidase inhibitory activity of H. ascyron extracts ($50-200{\mu}g/mL$ phenolics) was 0.00-14.81% and 15.33-47.49%, respectively. In cell viability, cell toxicity was shown at concentration of $100{\mu}g/mL$ and $30{\mu}g/mL$ of water and 90% ethanol extract. Therefore, $10-50{\mu}g/mL$ in water extracts and $5-20{\mu}g/mL$ in ethanol extracts was selected each for further study. Inducible nitric oxide synthase (iNOS) derived nitric oxide (NO) and cyclooxygenase (COX)-2-derived prostaglandin $E_2$ ($PGE_2$) protein expression inhibitory effect of extracts were inhibited in a dose dependent manner, significantly. Also, the pro-inflammatory cytokines inhibitory effect such as tumor necrosis $factor-{\alpha}$, nterleukin (IL)-6 and $IL-1{\beta}$ were decreased in the dose dependent manner. The results indicate that H. ascyron extracts reduced inflammatory responses in lipopolysaccharide-induced 264.7 cells via the regulation of the iNOS, COX-2, NO, $PGE_2$, and pro-inflammatory cytokines. Therefore, H. ascyron extracts have significant anti-inflammatory effect and a source as therapeutic materials.

• Journal of Life Science
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• v.28 no.11
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• pp.1361-1368
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• 2018

Inflammation is the most common condition in the human body. Tissue damage triggers inflammation, together with vasodilation and increased blood flow at the inflamed site, resulting in edema. Inflammatory responses are also triggered by lipopolysaccharide (LPS), a Toll-like receptor Enterococcus faecalis, a gram-positive organism, has been reported to possess immunomodulatory and preventive activities; however, its use may present risks of sepsis and other systemic infections. Heat-killed Enterococcus faecalis (EF-2001) has been reported to induce antitumor activity, but its effects on inflammation are not known. In the present study, we investigated the effect of EF-2001 on LPS-induced macrophage inflammatory responses. EF-2001 treatment reduced nitric oxide (NO) production, indicating suppression of inflammatory reactions. EF-2001 showed no cytotoxicity in macrophages. Further investigation of the anti-inflammatory mechanism of EF-2001 indicated that EF-2001 reduced the LPS-induced expression of inducible nitric oxide synthase and cyclooxygenase-2. EF-2001 also reduced f the LPS induction of several inflammatory molecules involved in the nuclear factor-${\kappa}B$ ($NF-{\kappa}B$) and mitogen-activated protein kinase pathways, including ERK, JNK, and p38 phosphorylation, in a concentration-dependent manner. Additionally, EF-2001 inhibited Akt phosphorylation and increased the expression of the inhibitory ${\kappa}B$ ($I{\kappa}B$) protein, an inhibitor of $NF-{\kappa}B$. EF-2001 also inhibited the nuclear translocation of p65. These results suggest that EF-2001 has anti-inflammatory properties and may be useful for treating inflammatory diseases.

• Journal of Life Science
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• v.27 no.8
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• pp.951-957
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• 2017

To understand the cytotoxic activity of Machilus thunbergii, which has been used as a traditional oriental medicine, the mechanism underlying the cytotoxic effect of its extract on human acute Jurkat T cells was investigated. The methanol extract of roots (3 kg) of M. thunbergii was evaporated, dissolved in, and then extracted by water. The water-extracted active substance was designated MTWE. When Jurkat T cells were treated with MTWE at concentrations of 0, 25, 50, and $100{\mu}g/ml$, the apoptotic phenomenon of cells accompanying several subsequent biochemical reactions, such as mitochondrial cytochrome c release, activation of caspase-3, and ICAD degradation, was detected in the Jurkat T cells. Moverover. the expression of Bcl-xL, which is a suppressor for mitochondrial cytochrome c release pathway, was reduced in the Jurkat T cells. As DUSP6, a growth suppressor of cancer cells, ranged from 0, 25, 50, $100{\mu}g/ml$ of MTWE, the expression level was elevated in the Jurkat T cells. The apoptotic morphological change of the nuclei was observed by DAPI staining. Although the potential involvement of the other factors and DUSP6 is currently being investigated in more detail, these findings support the notion that MTWE is able to achieve the apoptosis of Jurkat T cells, and it seems that MTWE is useful as a method of evaluating a chemotherapeutic agent or tonic materials for human acute leukemia.

• Applied Biological Chemistry
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• v.32 no.1
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• pp.23-29
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• 1989

Biochemical consequence of the accumulation in cells of superoxide $(O^{-}_{2})$ which was proposed to be probably a common chemical factor in the secondary process of the mechanism of chilling injury as well as in the visible light photodamage in cells of higher plants, has been investigated in the present work. Especially focused was the destructive effect of $O^{-}_{2}$ on the biochemical activity of mitochondria, as informations which support the suggestion that mitochondrial inner membrane is the major site of $O^{-}_{2}$ production have been collected. Mitochondria and submitochondrial particles (SMP) were prepared from soybean hypocotyls for this case study. When SMP were treated with the electrolytically produced $O^{-}_{2}$ they suffered not only inhibition of the membrane-bound enzymes as demonstrated by cytochrome c oxidase, but also lipid peroxidation of membrane as proved by malondialdehyde production. Malate dehydrogenase present in the protein extract from mitochondrial matrix was also inhibited by the $O^{-}_{2}$ treatment. These results exhibited the chaotic effect of the overproduction and accumulation of $O^{-}_{2}$ in cells under a certain abnormal circumstance such as environmental stress on the physiological function of mitochondrial; disruption of the cellular metabolic pathways and the structural integrity of membrane.