• Asian Pacific Journal of Cancer Prevention
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• 제13권7호
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• pp.3239-3245
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• 2012

Gliomas are a group of heterogeneous primary central nervous system tumors. Hyperthermia has proven to be a potential therapeutic tool for cancers in the clinic. However, the molecular mechanisms of hyperthermia remain unclear. The objective of this study was to investigate the effects of hyperthermia on the invasiveness in C6 glioma cells and related molecular pathways. Here our data show hyperthermia stimulated the release of tumor necrosis factor-alpha (TNF-${\alpha}$) and decreased C6 glioma cell migration and invasive capability at 30, 60, 120 and 180 min; with increased spontaneous apoptosis in C6 glioma cells at 120 min. We also found mitogen-activated protein kinase (P38 MAPK) protein expression to be increased and nuclear factor-kappa B (NF-${\kappa}B$) protein expression decreased. Based on the results, we conclude that hyperthermia alone reduced invasion of C6 glioma cells through stimulating TNF-${\alpha}$ signaling to activate apoptosis, enhancing P38 MAPK expression and inhibiting the NF-${\kappa}B$ pathway, a first report in C6 rat glioma cells.

• Biomolecules & Therapeutics
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• 제23권6호
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• pp.517-524
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• 2015

Human mesenchymal stem cells (MSCs) have been used in cell-based therapy to promote revascularization after peripheral or myocardial ischemia. High levels of reactive oxygen species (ROS) are involved in the senescence and apoptosis of MSCs, causing defective neovascularization. Here, we examined the effect of the natural antioxidant lycopene on oxidative stress-induced apoptosis in MSCs. Although $H_2O_2$ ($200{\mu}M$) increased intracellular ROS levels in human MSCs, lycopene ($10{\mu}M$) pretreatment suppressed $H_2O_2$-induced ROS generation and increased survival. $H_2O_2$-induced ROS increased the levels of phosphorylated p38 mitogen activated protein kinase (MAPK), Jun-N-terminal kinase (JNK), ataxia telangiectasia mutated (ATM), and p53, which were inhibited by lycopene pretreatment. Furthermore, lycopene pretreatment decreased the expression of cleaved poly (ADP ribose) polymerase-1 (PARP-1) and caspase-3 and increased the expression of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax), which were induced by $H_2O_2$ treatment. Moreover, lycopene significantly increased manganese superoxide dismutase (MnSOD) expression and decreased cellular ROS levels via the PI3K-Akt pathway. Our findings show that lycopene pretreatment prevents ischemic injury by suppressing apoptosis-associated signal pathway and enhancing anti-oxidant protein, suggesting that lycopene could be developed as a beneficial broad-spectrum agent for the successful MSC transplantation in ischemic diseases.

• The Korean Journal of Physiology and Pharmacology
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• 제12권4호
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• pp.137-142
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• 2008

Ceramide has emerged as a novel second messenger for intracellular signalling. It is produced from sphingomyelin and is involved in the control of cell differntiation, proliferation, and apoptosis. $C_2$-ceramide, short chain ceramide, plays a role in mediating contraction of cat esophageal smooth muscle cells. We examined the effect of synthesized ceramide analogues on the $C_2$-ceramide and ACh-induced contraction in esophageal smooth muscle cells isolated with collagenase. CY3523, CY3525, or CY3723 inhibited $C_2$-ceramide induced contraction, in a time dependent manne. Each analogue also inhibited the contraction in concentration dependent manners. CY 3523, CY 3525, and CY 3723 had no effect to the contraction induced by PMA. The inhibition with CY3523, CY3525 and CY3723 on the $C_2$-ceramide induced contraction was recovered by PMA. These analogues decreased the density of MAPK bands (p44/42 or p38) in the western blot. These results suggest that ceramide analogues can inhibit $C_2$-ceramide induced contraction via PKC and MAPK dependent pathway.

• Archives of Pharmacal Research
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• 제23권6호
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• pp.605-612
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• 2000

Green tea polyphenols (GTP) have been demonstrated to suppress tumorigenesis in several chemical-induced animal carcinogenesis models, and predicted as promising chemopreventive agents in human. Recent studies of GTP extracts showed the involvement of mitogen-activated protein kinases (MAPKs) in the regulation of Phase II enzymes gene expression and induction of apoptosis. In the current work we compared the biological actions of five green tea catechins: (1) induction of ARE reporter gene, (2) activation of MAP kinases, (3) cytotoxicity in human hepatoma HepG2-C8 cells, and (4) caspase activation in human cervical squamous carcinoma HeLa cells. For the induction of phase IIgene assay, (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG) potently induced antioxidant response element (ARE)-mediated luciferase activity, with induction observed at 25 $\mu\textrm{m}$with EGCG. The induction of ARE reporter gene appears to be structurally related to the 3-gallate group. Comparing the activation of MAPK by the five polyphenols, only EGCG showed potent activation of all three MAPKs (ERK, JNK and p38) in a dose- and time-dependent manner, whereas EGC activated ERK and p38. In the concentration range of 25 $\mu\textrm{m}$ to 1 mM, EGCG and ECG strongly suppressed HepG2-ARE-C8 cell-growth. To elucidate the mechanisms of green tea polyphenol-induced apoptosis, we measured the activation of an important cell death protein, caspase-3 induced by EGCG, and found that caspase-3 was activated in a dose- and time-dependent manner. Interestingly, the activation of caspase-3 was a relatively late event (peaked at 16 h), whereas activation of MAPKs was much earlier (peaked at 2 h). It is possible, that at low concentrations of EGCG, activation of MAPK leads to ARE-mediated gene expression including phase II detoxifying enzymes. Whereas at higher concentrations of EGCG, sustained activation of MAPKs such as JNK leads to apoptosis. These mechanisms are currently under investigation in our laboratory. As the most abundant catechin in GTP extract, we found that EGCG potently induced ARE-mediated gene expression, activated MAP kinase pathway, stimulated caspase-3 activity, and induced apoptosis. These mechanisms together with others, may contribute to the overall chemopreventive function of EGCG itself as well as the GTP.

• 생명과학회지
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• 제25권9호
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• pp.976-983
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• 2015

Achyranthoside C dimethyl ester (ACDE)는 우슬에서 분리한 oleanolic acid glycoside이다. 본 연구에서는 RAW264.7 대식세포에서 ACDE의 항염증 효과를 관찰하고 그 작용 기전을 연구하였다. ACDE는 세포에 독성을 유도하지 않으면서 heme oxygenase-1 (HO-1)의 발현을 유도하였다. ACDE 는 HO-1의 발현에 관여하는 전사인자인 nuclear factor E2-related factor 2 (Nrf2)를 핵으로 이동시켰다. 또한 ACDE에 의한 HO-1의 발현은 phosphatidylinositol 3-kinase (PI-3K) 및 mitogen activated protein kinases (MAPK) 억제제에 의해 감소되었으며, ACDE가 Akt, c-Jun kinase (JNK), extracellular signal regulated kinase (ERK), p38 kinase의 인산화를 유도하였다. 한편 ACDE는 lipopolysaccharide (LPS)로 인한 nitric oxide (NO)의 생성과 inducible NO synthase (iNOS) 발현을 억제하였으며 HO-1 siRNA를 처리했을 때 ACDE가 iNOS의 발현을 억제하지 못하였다. 이상의 결과를 종합해보면, ACDE는 대식세포에서 PI3K/Akt 및 MAPK와 Nrf2 신호전달과정을 통해 HO-1의 발현을 유도함으로써 NO와 같은 염증매개물질의 생성을 억제한다는 것을 알 수 있다. 이러한 연구결과는 ACDE가 항염증제로 사용될 수 있음을 시사한다.

• 대한한의학방제학회지
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• 제21권2호
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• pp.53-62
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• 2013

Objectives : Diabetic nephropathy is associated with morbidity and mortality of diabetes mellitus patients. Mesangial cell proliferation is known as the major pathologic features such as glomerulosclerosis. Oryeong-san, Korean formula, is widely used for the treatment of nephrosis, edema, and uremia. Oryeong-san is composed of five herbs: Alismatis Rhizoma, Polyporus, Atractylodis Rhizoma Alba, Hoelen, and Cinnamomi Cortex. Methods : The present study was performed to investigate potent inhibitory effect of Oryeong-san on high glucose (HG)-induced rat mesangial cells (RMC) proliferation. Results : RMC proliferation under 25 mM glucose was significantly accelerated compared with 5.5 mM glucose, which was inhibited by Oryeong-san in dose dependent manner. Pre-treatment of Oryeong-san induced down-regulation of cyclins/CDKs and up-regulation of CDK inhibitor, p21waf1/cip1 and p27kip1 expression. In addition, Oryeong-san reduced HG-induced RMC proliferation by suppressed the mitogen-activated protein kinase (MAPK) phospholyration such as extracellular signal regulated kinase (ERK), Jun N-terminal Kinase (JNK), and p38. Oryeong-san significantly suppressed HG-induced ROS production. Conclusions : Oryeong-san consequently inhibited HG-induced mesangial cell proliferation through the inhibition of MAPK and ROS signaling pathway. These results suggest that Oryeong-san may be effective in the treatment of renal dysfunction leading to diabetic nephropathy.

• 동의신경정신과학회지
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• 제25권4호
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• pp.423-434
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• 2014

Objectives: Activated microglia cells play an important role in inflammatory responses in the central nervous system (CNS) which are involved in neurodegenerative diseases. We attempted to determine the anti-inflammatory effects of Cheongnoimyungshin-hwan (CNMSH) in microglia cells. Methods: We examined the effect of CNMSH on the inflammatory responses in BV2 microglia cells induced by lipopolysaccharide (LPS) and explored the mechanism underlying the action of CNMSH. Results: BV2 cells treated with LPS showed an up-regulation of nitric oxide (NO), prostaglandin $PGE_2(PGE_2)$ and interleukin $1{\beta}(IL-1{\beta})$ release, whereas CNMSH suppressed this up-regulation. CNMSH inhibited the induction of COX-2, iNOS and $IL-1{\beta}$ proteins in LPS-treated BV2 cells and blocked the LPS-induced phosphorylation and nuclear translocation of nuclear factor ${\kappa}B(NF-{\kappa}B$). Furthermore, CNMSH attenuated the LPS-induced phosphorylation of extracellular signal-regulated kinase and p38 mitogen activated protein kinase (MAPK), as well as the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway, but did not inhibit the LPS-induced phosphorylation of c-Jun amino terminal kinase. Conclusions: These results suggest that the inhibitory effect of CNMSH on the LPS-induced production of inflammatory mediators and cytokines in BV2 cells is associated with the suppression of the $NF-{\kappa}B$ and PI3KAkt signaling pathways.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.250-257
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• 2023

Glutamate는 포유류의 중추신경계에 분포하는 흥분성 신경전달물질로, 기억, 인지, 그리고 학습 등에 있어서 중요한 역할을 한다. 하지만 고농도의 Glutamate는 신경세포에 독성을 유발하여 신경세포사멸을 유도함으로써 알츠하이머병, 파킨슨병, 뇌졸중 등의 신경퇴행성질환을 일으키는 것으로 알려져 있다. 본 연구에서 아열대 천연물의 항산화 활성과 신경보호 효과를 분석하였다. 11종의 아열대 추출물 중에서 Salacca wallichiana 추출물 (SE)의 라디칼 소거활성이 뛰어난 것으로 나타났다. 그리고 SE의 신경보호 효과를 조사한 결과 glutamate로 유도되는 cell death로부터 신경세포를 보호하였다. 또한 glutamate로 유도되는 apoptosis로부터 HT22 세포를 보호하는 효과는 Annexin V와 PI로 염색한 후 flow cytometry를 통해 분석되었다. 추가적으로 H₂DCFDA 염색을 이용하여 SE가 glutamate로 유도되는 세포 내 활성 산소 종 (ROS)을 억제한다는 것을 확인했다. SE의 신경보호 효과는 oxidative stress로 유발되는 Mitogen-activated protein kinase (MAPK) signaling pathway를 억제함으로써 신경세포를 보호하는 것으로 나타났다. 결과적으로 SE가 신경퇴행성질환을 예방하기 위한 치료제 개발에 기여할 수 있음을 나타낸다.

• Journal of Photoscience
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• 제9권2호
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• pp.229-232
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• 2002

There are two distinct UV-responsive signaling pathways in UV-irradiated mammalian cells, i.e., the DNA damage-dependent and -independent pathways. The former occurs in nucleus and results in growth arrest and apoptosis via post-translational modification of p53. The latter is initiated by oxidative stress and/or by damages in cell membrane or cytoplasm, which activate signaling cascade through intracellular molecules including mitogen activated protein kinases (MAPK). In normal human fibroblastic cells, all of MAPK family members, extracellular signal-related kinases (ERK), c-Jun N-terminal kinases (JNK) and p38, were rapidly phosphorylated following UV-irradiation. ERK phosphorylation was suppressed by an inhibitor of receptor tyrosine kinases (RTK). As ERK usually responds to mitogenic stimuli from RTK ligands, UV-induced ERK phosphorylation may be linked to the proliferation of survived cells. In contrast, phosphorylation of JNK and p38, as well as apoptosis, were modulated by the level of UV-generated oxidative stress Therefore, JNK and p38 may take part in oxidative stress-mediated apoptosis. Phosphorylation of p53 at Ser and Thr residues are essential for stabilization and activation of p53. Among several sites reported, we confirmed phosphorylation at Ser-15 and Ser-392 after UV-irradiation. Both of these were inhibited by a phosphoinositide 3-kinase inhibitor, presumably due to the shutdown of signals from DNA damage to p53. Phosphorylation at Ser-392 was also sensitive to an antioxidant and a p38 inhibitor, suggesting that Ser-392 of p53 is one of the possible points where DNA damage-dependent and -independent apoptic signals merge. Thus, MAPK pathway links UV-induced intracellular signals to the nuclear responses and modifies DNA damage-dependent cellular outcome, resulting in the determination of cell death.

• Biomolecules & Therapeutics
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• 제27권1호
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• pp.41-47
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• 2019

The apoptotic effects of shikonin (5,8-dihydroxy-2-[(1R)-1-hydroxy-4-methylpent-3-enyl]naphthalene-1,4-dione) on the human colon cancer cell line SNU-407 were investigated in this study. Shikonin showed dose-dependent cytotoxic activity against SNU-407 cells, with an estimated $IC_{50}$ value of $3{\mu}M$ after 48 h of treatment. Shikonin induced apoptosis, as evidenced by apoptotic body formation, sub-G_1$ phase cells, and DNA fragmentation. Shikonin induced apoptotic cell death by activating mitogen-activated protein kinase family members, and the apoptotic process was mediated by the activation of endoplasmic reticulum (ER) stress, leading to activation of the $PERK/elF2{\alpha}/CHOP$ apoptotic pathway, and mitochondrial $Ca^{2+}$ accumulation. Shikonin increased mitochondrial membrane depolarization and altered the levels of apoptosis-related proteins, with a decrease in B cell lymphoma (Bcl)-2 and an increase in Bcl-2-associated X protein, and subsequently, increased expression of cleaved forms of caspase-9 and -3. Taken together, we suggest that these mechanisms, including MAPK signaling and the ER- and mitochondria-mediated pathways, may underlie shikonin-induced apoptosis related to its anticancer effect.