• 한국식품영양학회지
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• 제28권3호
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• pp.343-350
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• 2015

Lonicera japonica 에탄올 추출물의 처리에 의하여 LPS에 의해서 활성화된 RAW 264.7 세포에서 NO의 생성량과 TNF-${\alpha}$, IL-$1{\beta}$ 및 IL-6와 같은 염증성 사이토카인의 분비를 억제하였고, MAPK family인 ERK, p38 및 JNK의 인산화와 $I{\kappa}-B{\alpha}$의 분해를 억제하였다. LPS로 유도한 endotoxin shock 동물실험에서 Lonicera japonica 에탄올 추출물 20 mg/kg에서 LPS로 유도한 endotoxin shock에 대한 생존율을 3배 이상 증가시켰으며, 생존시간도 1.3~1.4배 증가시켰다.

• Archives of Pharmacal Research
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• 제28권6호
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• pp.685-690
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• 2005

We recently reported that the ginseng saponin metabolite, compound K (20-O-$\beta$-D-glucopyra-nosyl-20(S)-protopanaxadiol, IH901), inhibits the growth of U937 cells through caspase-dependent apoptosis pathway. In this study, we further characterized the effects of compound K on U937 cells and found that, in addition to apoptosis, compound K induced the arrest of the G1 phase. The compound K treated U937 cells showed increased p21 expression; an inhibitory protein of cyclincdk complex. The up-regulation of p21 was followed by the inactivation of cyclin D and the cdk4 protein, which act at the early $G_1$ phase, and cyclin E, which acts at the late $G_1$ phase. Furthermore, compound K induced the activation of JNK and the transcription factor AP-1, which is a downstream target of JNK. These findings suggest that the up-regulation of p21 and activation of JNK in the compound K treated cells contribute to the arrest of the $G_1$ phase.

• 대한의생명과학회지
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• 제20권4호
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• pp.237-243
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• 2014

Triglyceride (TG) can cause death of macrophages and formation of foam cells thereby increasing inflammation in atherosclerotic plaques. Accumulation of cholesterol in macrophages is another critical event that promotes development of inflammatory cardiovascular diseases. Several proteins are known to transport intracellular cholesterol outside of the cell and these proteins are thought to be protective against atherosclerosis pathogenesis. It is unknown whether TG can affect cholesterol efflux in macrophages. In the current study, we examined mRNA expression levels of genes that promote efflux of cholesterol (ABCA1, ABCG1 and SR-B1). We found that TG treated THP-1 macrophages exhibited an increase in ABCG1 expression in a dose- and time-dependent manner. In contrast, the expression of ABCA1 and SR-B1 remained unchanged. To identify cell signaling pathways that participate in up-regulation of ABCG1, THP-1 macrophages were treated with various cell signaling inhibitors. We found that inhibition of the JNK and p38 MAPK pathway completely abrogated up-regulation of ABCG1 whereas inhibition of MEK1 further enhanced ABCG1 expression in TG treated THP-1 macrophages. Also, TG induced phosphorylation of JNK and p38 MAPK in THP-1 macrophages. These results suggest that TG may potentially influence cholesterol efflux in macrophages.

• Journal of Ginseng Research
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• 제43권1호
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• pp.95-104
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• 2019

Background: Oxidized low-density lipoprotein (ox-LDL) causes vascular endothelial cell inflammatory response and apoptosis and plays an important role in the development and progression of atherosclerosis. Ginsenoside compound K (CK), a metabolite produced by the hydrolysis of ginsenoside Rb1, possesses strong anti-inflammatory effects. However, whether or not CK protects ox-LDL-damaged endothelial cells and the potential mechanisms have not been elucidated. Methods: In our study, cell viability was tested using a 3-(4, 5-dimethylthiazol-2yl-)-2,5-diphenyl tetrazolium bromide (MTT) assay. Expression levels of interleukin-6, monocyte chemoattractant protein-1, tumor necrosis factor-${\alpha}$, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 were determined by enzyme-linked immunosorbent assay and Western blotting. Mitochondrial membrane potential (${\Delta}{\Psi}m$) was detected using JC-1. The cell apoptotic percentage was measured by the Annexin V/ propidium iodide (PI) assay, lactate dehydrogenase, and caspase-3 expression. Apoptosis-related proteins, nuclear factor $(NF)-{\kappa}B$, and mitogen-activated protein kinases (MAPK) signaling pathways protein expression were quantified by Western blotting. Results: Our results demonstrated that CK could ameliorate ox-LDL-induced human umbilical vein endothelial cells (HUVECs) inflammation and apoptosis, $NF-{\kappa}B$ nuclear translocation, and the phosphorylation of p38 and c-Jun N-terminal kinase (JNK). Moreover, anisomycin, an activator of p38 and JNK, significantly abolished the anti-apoptotic effects of CK. Conclusion: These results demonstrate that CK prevents ox-LDL-induced HUVECs inflammation and apoptosis through inhibiting the $NF-{\kappa}B$, p38, and JNK MAPK signaling pathways. Thus, CK is a candidate drug for atherosclerosis treatment.

• Biomolecules & Therapeutics
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• 제31권1호
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• pp.73-81
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• 2023

Sirtuins (SIRTs) belong to the nicotinamide adenine dinucleotide (NAD+)-dependent class III histone deacetylase family. They are key regulators of cellular and physiological processes, such as cell survival, senescence, differentiation, DNA damage and stress response, cellular metabolism, and aging. SIRTs also influence carcinogenesis, making them potential targets for anticancer therapeutic strategies. In this study, we investigated the anticancer properties and underlying molecular mechanisms of a novel SIRT1 inhibitor, MHY2251, in human colorectal cancer (CRC) cells. MHY2251 reduced the viability of various human CRC cell lines, especially those with wild-type TP53. MHY2251 inhibited SIRT1 activity and SIRT1/2 protein expression, while promoting p53 acetylation, which is a target of SIRT1 in HCT116 cells. MHY2251 treatment triggered apoptosis in HCT116 cells. It increased the percentage of late apoptotic cells and the sub-G1 fraction (as detected by flow cytometric analysis) and induced DNA fragmentation. In addition, MHY2251 upregulated the expression of FasL and Fas, altered the ratio of Bax/Bcl-2, downregulated the levels of pro-caspase-8, -9, and -3 proteins, and induced subsequent poly(ADP-ribose) polymerase cleavage. The induction of apoptosis by MHY2251 was related to the activation of the caspase cascade, which was significantly attenuated by pre-treatment with Z-VAD-FMK, a pan-caspase inhibitor. Furthermore, MHY2251 stimulated the phosphorylation of c-Jun N-terminal kinase (JNK), and MHY2251-triggered apoptosis was blocked by pre-treatment with SP600125, a JNK inhibitor. This finding indicated the specific involvement of JNK in MHY2251-induced apoptosis. MHY2251 shows considerable potential as a therapeutic agent for targeting human CRC via the inhibition of SIRT1 and activation of JNK/p53 pathway.

• 한국식품영양학회지
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• 제28권4호
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• pp.579-585
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• 2015

Rutin은 메밀에 함유되어 있는 것으로 잘 알려져 있는 flavonoid 물질로서, 최근 연구들에서 rutin의 항염증 및 암예방 활성이 보고되어져 왔다. 그러나, rutin의 암예방 활성과 관련된 분자생물학적 기전에 대한 연구는 아직까지 미비한 실정이다. 따라서, 본 연구에서는 발암 과정 중 하나인 세포의 악성 변형을 EGF로 유도하여 rutin이 이를 억제하는지 여부를 확인하는 실험을 진행하였으며, 그 분자생물학적 기전을 규명하고자 하였다. Soft agar assay 실험 결과, rutin은 EGF로 유도된 세포의 악성 변형을 $25{\mu}M$, $50{\mu}M$, $100{\mu}M$에서 농도별로 감소시켰다. 또한 EGF로 유도된 MEK/ERK 및 MKK4/JNK 신호전달체계의 인산화를 저해하였다. 그러나 이와는 대조적으로 rutin은 EGF로 유도된 MKK3/6/p38 신호전달체계 인산화는 감소시키지 못하는 것으로 확인되었다. 이상의 연구결과들은 rutin이 암화 과정 중 발생되는 세포의 악성변형 과정을 촉진시킨다고 잘 알려져 있는 MEK/ERK 및 MKK4/JNK 신호전달체계의 활성화를 억제함으로써 암예방 활성을 나타낸다는 것을 제시하고 있으며, 이는 메밀의 생리활성 성분인 rutin의 암예방 생리 활성 소재로서의 이용 가능성을 보여주는 중요한 연구 결과라 할 수 있겠다. 또한 위 연구결과는 MEK/ERK 및 MKK4/JNK 신호전달 체계를 표적으로 하는 생리활성 소재 탐색에도 활용 가능할 것으로 생각되어진다.

• Archives of Pharmacal Research
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• 제26권9호
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• pp.739-746
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• 2003

Ultraviolet B (UVB) is known to induce apoptosis in human melanocytes. Here we show the cytoprotective effect of sphingosine-1-phosphate (S1P) against UVB-induced apoptosis. We also show that UVB-induced apoptosis of melanocytes is mediated by caspase-3 activation and poly(ADP-ribose) polymerase (PARP) cleavage, and that S1P prevents apoptosis by inhibiting this apoptotic pathway. We further investigated three major mitogen-activated protein (MAP) kinases after UVB irradiation. UVB gradually activated c-Jun N-terminal kinase (JNK) and p38 MAP kinase, while extracellular signal-regulated protein kinase (ERK) was inactivated transiently. Blocking of the p38 MAP kinase pathway using SB203580 promoted cell survival and inhibited the activation of caspase-3 and PARP cleavage. These results suggest that p38 MAP kinase activation may play an important role in the UVB-induced apoptosis of human melanocytes. To explain this cytoprotective effect, we next examined whether S1P could inhibit UVB-induced JNK and p38 MAP kinase activation. However, S1P was not found to have any influence on UVB-induced JNK or p38 MAP kinase activation. In contrast, S1P clearly stimulated the phosphorylation of ERK, and the specific inhibition of the ERK pathway using PD98059 abolished the cytoprotective effect of S1P. Based on these results, we conclude that the activation of p38 MAP kinase plays an important role in UVB-induced apoptosis, and that S1P may show its cytoprotective effect through ERK activation in human melanocytes.

• Asian Pacific Journal of Cancer Prevention
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• 제17권5호
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• pp.2637-2641
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• 2016

Tumor necrosis factor ($TNF-{\alpha}$), an inflammatory cytokine that plays an important role in the control of cell proliferation, differentiation, and apoptosis, has previously been used in anti-cancer therapy. However, the therapeutic applications of $TNF-{\alpha}$ are largely limited due to its general toxicity and anti-apoptotic influence. To overcome this problem, the present study focused on the effect of active constituents isolated from a medicinal plant on $TNF-{\alpha}$-induced apoptosis in human colon adenocarcinoma (HT-29) cells. Nimbolide from Azadirachta indica was evaluated for cytotoxicity by methyl tetrazolium 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay and phase contrast microscopy. Effects on apoptotic signaling proteins were investigated using Western blot analysis. Nimbolide showed cytotoxicity against HT-29 cells that was significantly different from the control group (p<0.01), a concentration of $10{\mu}M$ significantly inducing cell death (p<0.01). In combination with $TNF-{\alpha}$, nimbolide significantly enhanced-induced cell death. In apoptotic pathway, nimbolide activated c-Jun N-terminal kinase (JNK) phosphorylation, BH3 interacting-domain death agonist (Bid) and up-regulated the death receptor 5 (DR5) level. In the combination group, nimbolide markedly sensitized $TNF-{\alpha}$-induced JNK, Bid, caspase-3 activation and the up-regulation of DR5. Our findings overall indicate that nimbolide may enhance $TNF-{\alpha}$-mediated cellular proliferation inhibition through increasing cell apoptosis of HT-29 cells by up-reglation of DR5 expression via the JNK pathway.

• 한국자원식물학회지
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• 제36권4호
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• pp.257-263
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• 2023

본 연구에서 인가목 잎 추출물이 RAW264.7 세포에서 면역자 극인자의 생성을 증가시키고 포식작용의 활성화를 유도한다는 것을 확인하였다. 게다가 인가목 잎 추출물은 TLR4 의존적 JNK와 PI3K/AKT 신호전달 활성화를 통해 자가포식을 유도한다는 것을 확인하였다. 대식세포의 활성화와 자가포식은 선천면역반응과 후천면역반응을 향상시킬 수 있는 주요 전략 중 하나이기 때문에 인가목 잎 추출물은 인체의 면역반응을 증가시킬 수 있는 건강기능식품이나 보조제로 활용될 수 있을 것으로 생각된다. 그러나 본 연구에서는 작용기전을 구명하기 위해 관련된 단일억제제를 사용하였기 때문에 명확한 작용기전 구명을 위해 다양한 억제제 또는 siRNA를 활용한 추가적 연구가 필요하다고 판단된다.

• 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.