• Molecules and Cells
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• 제24권3호
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• pp.378-387
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• 2007

The Bcl-2 family of proteins interacts at the mitochondria to regulate apoptosis. However, the anti-apoptotic Bcl-2 and $Bcl-X_L$ are not completely localized to the mitochondria. In an attempt to generate Bcl-2 and $Bcl-X_L$ chimeras that are constitutively localized to the mitochondria, we substituted their C-terminal transmembrane tail or both the C-terminal transmembrane tail and the adjacent loop with the equivalent regions from Bak or Bax mutant (BaxS184V) as these regions determine the mitochondrial localization of Bak and Bax. The effects of these substitutions on subcellular localization and their activities were assessed following expression in HeLa and CHO K1 cells. The substitution of the C-terminal tail or the C-terminal tail and the adjacent loop of Bcl-2 with the equivalent regions from Bak or the Bax mutant resulted in its association with the mitochondria. This change in subcellular localization of Bcl-2 chimeras triggered cells to undergo apoptotic-like cell death. The localization of this Bcl-2 chimera to the mitochondria may be associated with the disruption of mitochondrial membrane potential. Unlike Bcl-2, the loop structure adjacent to the C-terminal tail in $Bcl-X_L$ is crucial for its localization. To localize the $Bcl-X_L$ chimeras to the mitochondria, the loop structure next to the C-terminal tail in $Bcl-X_L$ protein must remain intact and cannot be substituted by the loop from Bax or Bak. The chimeric $Bcl-X_L$ with both its C-terminal tail and the loop structure replaced by the equivalent regions of Bak or Bax mutant localized throughout the entire cytosol. The $Bcl-X_L$ chimeras that are targeted to the mitochondria and the wild type $Bcl-X_L$ provided same protection against cell death under several death inducing conditions.

• 동의생리병리학회지
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• 제19권3호
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• pp.671-676
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• 2005

In this study, we investigated the antioxidant effect of extract from Monascus pillosus, on the human wild-type p53 and p21 expressing A549 lung epithelial cell line and MCF-7 mammary adenocarcinoma cell line stimulated by NO. $P21^{waf/cip1}$ was identified as a gene induced in senescent cells. It is a cyclin-dependent kinase inhibitor and has been shown to cause cell cycle arrest and apoptosis. While p53-regulated stimulation of p21 appears to be central for the permanent growth-arrest, the role of p21 in p53-triggered cell death is unclear. Low dose of sodium nitroprusside (SNP) induced the development of senescence associated with increased expression of p53 and p21 in A549 cells. Inhibition of p21 transactivating activity requires high level correlates with the amount of p53 necessary to cause cell death. Association of p21 and p53 results in inhibition of p21-stimulated transcription. This requires a higher p53 level than is necessary for transcriptional activation of endogenous p53-responsive gene but correlates well with the level of p53 necessary to cause cell death. Exposure to W-1 inhibited oxidative stresses-induced senescence-like arrest, resulting in a significant reduction in p53 and p21 steady state levels. These results suggest that p53 and p21 play a central role in the onset of senescence. Thus, it is important to emphasize control of oxidative balance in tumor prevention and aging.

• Molecules and Cells
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• 제38권4호
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• pp.349-355
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• 2015

EphA7 has been implicated in the regulation of apoptotic cell death in neural epithelial cells. In this report, we provide evidence that EphA7 interacts with caspase-8 to induce apoptotic cell signaling. First, a pull-down assay using biotinylated ephrinA5-Fc showed that EphA7 co-precipitated with wild type caspase-8 or catalytically inactive caspase-8 mutant. Second, co-transfection of EphA7 with caspase-8 significantly increased the number of cleaved caspase-3 positive apoptotic cells under an experimental condition where transfection of EphA7 or caspase-8 alone did not affect cell viability or apoptosis. EphA4 also had a causative role in inducing apoptotic cell death with caspase-8, whereas EphA8 did not. Third, caspase-8 catalytic activity was essential for the apoptotic signaling cascade, whereas tyrosine kinase activity of the EphA4 receptor was not. Interestingly, we found that kinase-inactive EphA4 was well co-localized at the plasma membrane with catalytically inactive caspase-8, suggesting that an interaction between these mutant proteins was more stable. Finally, we observed that the extracellular region of the EphA7 receptor was critical for interacting with caspase-8, whereas the cytoplasmic region of EphA7 was not. Therefore, we propose that Eph receptors physically associate with a transmembrane protein to form an apoptotic signaling complex and that this unidentified receptor-like protein acts as a biochemical linker between the Eph receptor and caspase-8.

• Nutrition Research and Practice
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• 제11권6호
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• pp.445-451
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• 2017

BACKGROUND/OBJECTIVES: Endoplasmic reticulum (ER) stress is positively associated with atherosclerosis via elevating macrophage cell death and plaque formation, in which oxidative stress plays a pivotal role. Antioxidative, lipid-lowering, and anti-atherogenic effects of kimchi, a Korean fermented vegetable, have been established, wherein capsaicin, ascorbic acid, quercetin, 3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid, and lactic acids were identified. In this study, mechanisms of action of kimchi methanol extracts (KME) on fatty streak formation via suppression of ER stress and apoptosis in aorta were examined in low-density lipoprotein receptor knockout mice. MATERIALS AND METHODS: Mice fed a high cholesterol diet with an oral administration of KME (KME group, $200 mg{\cdot}kg-bw^{-1}{\cdot}day^{-1}$) or distilled water (control group) for 8 weeks (n = 20 for group). Plasma lipid and oxidative stress levels were evaluated. Protein expression was measured by western blot assay. Fatty streak lesion size and the degree of apoptosis were examined in the aorta. RESULTS: Compared to the control group, in the KME group, plasma lipids levels were decreased and oxidative stress was alleviated (P < 0.05). Protein expression levels of nuclear factor (erythroid-derived 2)-like 2-mediated antioxidants in aorta were increased whereas those for ER stress markers, glucose regulated protein 78, phospho-protein kinase RNA-like ER kinase, phospho-eukaryotic initiation factor 2 subunit ${\alpha}$, X-box binding protein 1, and C/EBP homologous protein were decreased in the KME group (P < 0.05). Moreover, apoptosis was suppressed via downregulation of phospho-c-Jun N-terminal kinase, bcl-2-associated X protein, caspases-9, and -3 with a concomitant upregulation of anti-apoptotic protein, B-cell lymphoma 2 (P < 0.05). Fatty streak lesion size was reduced and the degree of apoptosis was less severe in the KME group (P < 0.05). CONCLUSIONS: In conclusion, antioxidant activity of KME might prevent fatty streak formation through, in part, inhibition of ER stress and apoptosis in aortic sinus where macrophages are harbored.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.5783-5788
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• 2013

Trigonella foenum in graecum (Fenugreek) is a traditional herbal plant used to treat disorders like diabetes, high cholesterol, wounds, inflammation, gastrointestinal ailments, and it is believed to have anti-tumor properties, although the mechanisms for the activity remain to be elucidated. In this study, we prepared a methanol extract from Fenugreek whole plants and investigated the mechanism involved in its growth-inhibitory effect on MCF-7 human breast cancer cells. Apoptosis of MCF-7 cells was evidenced by investigating trypan blue exclusion, TUNEL and Caspase 3, 8, 9, p53, FADD, Bax and Bak by real-time PCR assays inducing activities, in the presence of FME at $65{\mu}g/mL$ for 24 and 48 hours. FME induced apoptosis was mediated by the death receptor pathway as demonstrated by the increased level of Fas receptor expression after FME treatment. However, such change was found to be absent in Caspase 3, 8, 9, p53, FADD, Bax and Bak, which was confirmed by a time-dependent and dose-dependent manner. In summary, these data demonstrate that at least 90% of FME induced apoptosis in breast cell is mediated by Fas receptor-independently of either FADD, Caspase 8 or 3, as well as p53 interdependently.

• 대한한의학회지
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• 제24권2호
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• pp.179-192
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• 2003

Objectives : Boyanghwanoh-tang (Buyanhaiwu-tang) has been used as a prescription for stroke, senile and vascular dementia, ischemic brain and heart damage in Oriental traditional medicine. However, there is little known about the mechanism by which the water extracts of Boyanghwanoh-tang (Buyanhaiwu-tang) rescue cells fromthese damages, and little is known about the protective mechanisms of Boyanghwanoh-tang (Buyanhaiwu-tang) on oxidative stress in neuronal cells. Therefore, we have investigated the role of Boyanghwanoh-tang (Buyanhaiwu-tang) on serum and glucose deprived apoptosis in PC12 cells. Methods : PC12 Cells have been used extensively as a model for studying the cellular and molecular effects of neuronal cells. The viability of cells was measured by MIT assay. We used DNA fragmentation and caspase 1, 2, 3, 6, 9-likeproteases activation assay. Transcriptional activation of NF-kB was assessed by using electrophoretic mobility shift assay. Results : Boyanghwanoh-tang (Buyanhaiwu-tang) rescued PC12 cells from apoptotic death by serum and glucose deprivation in a dose-dependent manner. The nuclear staining of PC12 cells clearly showed that Boyanghwanoh-tang (Buyanhaiwu-tang) attenuated nuclear condensation and fragmentation, which represent typical neuronal apoptotic characteristics. Boyanghwanoh-tang (Buyanhaiwu-tang) also prevents fragmentation of genomic DNA and activation of caspase 3-like protease in serum and glucose deprived PC12 cells. Furthermore, Boyanghwanoh-tang (Buyanhaiwu-tang) reduced the activation of NF-kB by serum and glucose-deprived apoptosis. Conclusions : These findings suggest that serum and glucose deprivation induces reduced glutathione (GSH) depletion, and consequently, apoptosis through endogenously produced reactive oxygen species in PC12 cells. Also, our data indicated that Boyanghwanoh-tang (Buyanhaiwu-tang) has protective effects against the serum and glucose deprived deaths of PC12 cells, which are mediated by the generation of GSH that, in turn, can reduce oxidative stress caused by reactive oxygen species (ROS) such as hydrogen peroxide.

• 셀메드
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• 제3권1호
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• pp.9.1-9.10
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• 2013

In traditional systems of medicine including homeopathy, the Condurango extract (Con) is often used to cure stomach cancer mainly, without having any scientific validation of its anti-cancer ability. Con has therefore been tested against non-small-cell lung cancer cells (NSCLC) A549 and NCI-H522 (H522) known to contain the KRAS mutation, making them resistant to most chemotherapeutic agents. As cancer cells generally defy cytotoxicity developed by chemopreventive agents and escape cell death, any drug showing the capability of preferentially killing cancer cells through apoptosis is worth consideration for judicious application. A549 and H522 cells were exposed to $0.35{\mu}g/{\mu}l$ and $0.25{\mu}g/{\mu}l$ of Con, respectively, for 48 h and analysed based on various protocols associated with apoptosis and DNA damage, such as MTT assay to determine cell viability, LDH assay, DNA fragmentation assay, comet assay, and microscopical examinations of DNA binding fluorescence stains like DAPI, Hoechst 33258 and acridine orange/ethidium bromide to determine the extent of DNA damage made in drug-treated and untreated cells and the results compared. Changes in mitochondrial membrane potential and the generation of reactive oxygen species were also documented through standard techniques. Con killed almost 50% of the cancer cells but spared normal cells significantly. Fluorescence studies revealed increased DNA nick formation and depolarized membrane potentials after drug treatment in both cell types. Caspase-3 expression levels confirmed the apoptosis-inducing potential of Con in both the NSCLC lines. Thus, overall results suggest considerable anticancer potential of Con against NSCLC in vitro, validating its use against lung cancer by practitioners of traditional medicine including homeopathy.

• Toxicological Research
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• 제17권3호
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• pp.215-223
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• 2001

카드뮴의 주요한 표적장기이며 카드뮴이 만성 및 급성 폭로시 축적되는 가장 중요한 장기인 간의 세포독성을 Hepalclc7세포에서 caspases및 Bax단백질의 활성과 발현 그리고 미토콘드리아 세포막 전위 변화(MPT) 등을 조사하여 다음과 같은 결과를 얻었다. 1. 카드뮴은 농도의존적으로 간세포인 Hepalclc7 세포의 생존율을 감소시켰다. 2. 카드뮴을 농도별로 처리하였을 때 100 M 이상의 농도에서 세포사멸의 특징중의 하나인 DNA분절현상을 확인하였다. 3. 카드뮴 처리 후 caspase-3, caspase-8, caspase-9 의 활성변화를 조사한 결과 caspase-3,-9 pretease 활성이 시간이 경과함에 따라 증가하였다. 4. 카드뮴 처리 후 cytochrome c가 세포질내로 방출되었고 이는 caspase-9 proteas의 활성화를 유도하였다. 5. 카드뮴 처리 후 Bax가 세포질에서 미토콘드리아로 이동하여 cytochrome c의 세포질내로의 방출에 관여하였다. 6. 카드뮴 처리시 미토콘드리아 세포막 전위차의 감소를 JC-1 형광염색을 통하여 확인하였다. 이상의 결과는 카드뮴에 의한 Hepalclc7 세포사멸의 신호전달기전은 세포질내에 있는 Bax가 미토콘드리아로 이동, cytochrome c의 세포질내로의 방출, 그리고 caspase-3, 9 pretease 활성화를 의해서 매개되는 것으로 판단된다. 또한 Bax 단백질의 발현변화가 미토콘드리아의 기능변화에 기여하였으리라 사료된다.

• Molecules and Cells
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• 제45권4호
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• pp.257-272
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• 2022

In addition to inducing apoptosis, caspase inhibition contributes to necroptosis and/or autophagy depending on the cell type and cellular context. In macrophages, necroptosis can be induced by co-treatment with Toll-like receptor (TLR) ligands (lipopolysaccharide [LPS] for TLR4 and polyinosinic-polycytidylic acid [poly I:C] for TLR3) and a cell-permeable pan-caspase inhibitor zVAD. Here, we elucidated the signaling pathways and molecular mechanisms of cell death. We showed that LPS/zVAD- and poly I:C/zVAD-induced cell death in bone marrow-derived macrophages (BMDMs) was inhibited by receptor-interacting protein kinase 1 (RIP1) inhibitor necrostatin-1 and autophagy inhibitor 3-methyladenine. Electron microscopic images displayed autophagosome/autolysosomes, and immunoblotting data revealed increased LC3II expression. Although zVAD did not affect LPS- or poly I:C-induced activation of IKK, JNK, and p38, it enhanced IRF3 and STAT1 activation as well as type I interferon (IFN) expression. In addition, zVAD inhibited ERK and Akt phosphorylation induced by LPS and poly I:C. Of note, zVAD-induced enhancement of the IRF3/IFN/STAT1 axis was abolished by necrostatin-1, while zVAD-induced inhibition of ERK and Akt was not. Our data further support the involvement of autocrine IFNs action in reactive oxygen species (ROS)-dependent necroptosis, LPS/zVAD-elicited ROS production was inhibited by necrostatin-1, neutralizing antibody of IFN receptor (IFNR) and JAK inhibitor AZD1480. Accordingly, both cell death and ROS production induced by TLR ligands plus zVAD were abrogated in STAT1 knockout macrophages. We conclude that enhanced TRIF-RIP1-dependent autocrine action of IFNβ, rather than inhibition of ERK or Akt, is involved in TLRs/zVAD-induced autophagic and necroptotic cell death via the JAK/STAT1/ROS pathway.

• 생명과학회지
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• 제18권11호
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• pp.1485-1492
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• 2008

Prostaglandin $A_2$ ($PGA_2$)는 사람 골육종 세포인 U2OS 세포주에서 apoptosis와 heme oxygenase (HO)-1의 발현을 함께 유도하였다. $PGA_2$에 의한 apoptosis는 HO-1의 과도한 발현이나 HO-1에 대한 small interfering RNA에 의한 발현저하에 의하여 변동되지 않았으나 $H_2O_2$에 의한 세포사망은 HO-1의 발현 수준에 반비례하여 변동되었다. 또한 thiol antioxidant인 N-acetyl-L-cysteine (NAC)은 $PGA_2$에 의한 세포사망과 HO-1의 발현 증가를 모두 차단하였지만, non-thiol antioxidant인 butylated hydroxyanisole (BHA)과 ascorbic acid는 세포사망과 HO-1의 발현 유도를 차단하지 않았다. 이와 같은 결과들은 $PGA_2$는 산화성 손상에 의해서가 아니라 $PGA_2$의 thiol-reactivity에 의하여 apoptosis와 HO-1의 발현을 유도하며, HO-1의 발현은 $PGA_2$에 의한 apoptosis와는 독립적인 현상이거나 기능적으로 apoptosis 유도의 하부에 위치하고 apoptosis의 진행에는 기여하지 않을 것이라는 것을 시사해 준다.