• Journal of Microbiology and Biotechnology
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• v.32 no.5
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• pp.645-656
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• 2022

Gossypol, a natural phenolic aldehyde present in cotton plants, was originally used as a means of contraception, but is currently being studied for its anti-proliferative and anti-metastatic effects on various cancers. However, the intracellular mechanism of action regarding the effects of gossypol on pancreatic cancer cells remains unclear. Here, we investigated the anti-cancer effects of gossypol on human pancreatic cancer cells (BxPC-3 and MIA PaCa-2). Cell counting kit-8 assays, annexin V/propidium iodide staining assays, and transmission electron microscopy showed that gossypol induced apoptotic cell death and apoptotic body formation in both cell lines. RNA sequencing analysis also showed that gossypol increased the mRNA levels of CCAAT/enhancer-binding protein homologous protein (CHOP) and activating transcription factor 3 (ATF3) in pancreatic cancer cell lines. In addition, gossypol facilitated the cleavage of caspase-3 via protein kinase RNA-like ER kinase (PERK), CHOP, and Bax/Bcl-2 upregulation in both cells, whereas the upregulation of ATF was limited to BxPC-3 cells. Finally, a three-dimensional culture experiment confirmed the successful suppression of cancer cell spheroids via gossypol treatment. Taken together, our data suggest that gossypol may trigger apoptosis in pancreatic cancer cells via the PERK-CHOP signaling pathway. These findings propose a promising therapeutic approach to pancreatic cancer treatment using gossypol.

• BMB Reports
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• v.49 no.4
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• pp.208-213
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• 2016

Prolonged ER stress (ERS) can be associated with the induction of apoptotic cell death in various heart diseases. In this study, we searched for microRNAs affecting ERS in the heart using in silico and in vitro methods. We found that miR-185 directly targets the 3′-untranslated region of Na⁺/H⁺ exchanger-1 (NHE-1), a protein involved in ERS. Cardiomyocyte ERS-triggered apoptosis induced by 100 ng/ml tunicamycin (TM) or 1 μM thapsigargin (TG), ERS inducers, was significantly reduced by miR-185 overexpression. Protein expression of pro-apoptotic markers such as CCAAT/enhancer-binding protein homologous protein (CHOP) and cleaved-caspase-3 was also markedly reduced by miR-185 in a dose-dependent manner. Cariporide (20 μM), a pharmacological inhibitor of NHE-1, also attenuated ERS-induced apoptosis in cardiomyocytes and CHOP protein expression, suggesting that NHE-1 plays an important role in ERS-associated apoptosis in cardiomyocytes. Collectively, the present results demonstrate that miR-185 is involved in cardio-protection against ERS-mediated apoptotic cell death.

• Journal of Life Science
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• v.26 no.4
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• pp.490-495
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• 2016

Brefeldin A (BFA), a lactone antibiotic isolated from the fungus Eupenicillium brefeldianum, inhibits the transport of secreted and membrane proteins from the endoplasmic reticulum (ER) to the Golgi apparatus. BFA disrupts Golgi function, the accumulation of unfolded proteins in ER, and the induction of ER stress. Prolonged ER stress induces apoptosis at least in part through the transcription factor C/EBP (CCAAT/enhancer binding protein) homologous protein (CHOP),which is activated by the unfolded protein response (UPR). In this paper, we demonstrate that BFA-induced endoplasmic reticulum stress leads to different CHOP expression in primary astrocyte cells and C6 glioma cells. BFA induced lower CHOP expression levels in primary astrocyte cells than in C6 glioma cells; however, other ER stress inducers (thapsigargin and tunicamycin) resulted in similar expression patterns in these two cell types. Interestingly, the three different ER stress inducers (BFA, thapsigargin, and tunicamycin) induced similar levels of CHOP mRNA expression in primary astrocyte cells. The ubiquitin-proteasome inhibitor MG132 also markedly up-regulated the BFA-mediated CHOP protein expression in primary astrocyte cells. BFA also induced higher proteasome activity in primary astrocyte cells than in C6 glioma cells. Taken together, our results suggest that higher proteasomal activity might down-regulate BFA-induced CHOP expression in primary astrocyte cells.

• Nutrition Research and Practice
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• v.13 no.2
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• pp.95-104
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• 2019

BACKGROUND/OBJECTIVES: Inflammatory Bowel Disease (IBD) has rapidly escalated in Asia (including Korea) due to increasing westernized diet patterns subsequent to industrialization. Factors associated with endoplasmic reticulum (ER) stress are demonstrated to be one of the major causes of IBD. This study was conducted to investigate the effect of Lycium barbarum (L. barbarum) on ER stress. MATERIALS/METHODS: Mouse embryonic fibroblast (MEF) cell line and polarized Caco-2 human intestinal epithelial cells were treated with crude extract of the L. chinense fruit (LF). Paracellular permeability was measured to examine the effect of tight junction (TJ) integrity. The regulatory pathways of ER stress were evaluated in MEF knockout (KO) cell lines by qPCR for interleukin (IL) 6, IL8 and XBP1 spliced form (XBP1s). Immunoglobulin binding protein (BiP), XBP1s and CCAAT/enhancer-binding homologous protein (CHOP) expressions were measured by RT-PCR. Scanning Ion Conductance Microscopy (SICM) at high resolution was applied to observe morphological changes after treatments. RESULTS: Exposure to LF extract strengthened the TJ, both in the presence and absence of inflammation. In polarized Caco-2 pretreated with LF, induction in the expression of proinflammatory marker IL8 was not significant, whereas ER stress marker XBP1s expression was significantly increased. In wild type (wt) MEF cells, IL6, CHOP and XBP1 spliced form were dose-dependently induced when exposed to $12.5-50{\mu}g/mL$ extract. However, absence of XBP1 or $IRE1{\alpha}$ in MEF cells abolished this effect. CONCLUSION: Results of this study show that LF treatment enhances the barrier function and reduces inflammation and ER stress in an $IRE1{\alpha}$-XBP1-dependent manner. These results suggest the preventive effect of LF on healthy intestine, and the possibility of reducing the degree of inflammatory symptoms in IBD patients.

• Journal of Life Science
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• v.29 no.3
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• pp.295-302
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• 2019

Liquiritigenin (LG) is a chiral flavonoid isolated from the roots of licorice. It exhibits multiple biological activities including anti-oxidant, anti-cancer, and anti-inflammatory effects. In particular though, the anti-cancer activity of LG in oral squamous cell carcinoma has yet to be elucidated, and LG-induced apoptosis in oral squamous cell carcinoma remains poorly understood. In the present study, we tested the role of LG in inducing apoptosis in oral squamous cell carcinoma cells. LG treatment of HN22 cells resulted in a dose-dependent inhibition of cell viability as detected by a 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide assay. The induction of apoptosis in terms of Annexin V/7-Aminoactinomycin D staining, sub-G1 population, and multi-caspase activity were assessed with a $Muse^{TM}$ Cell Analyzer. Flow cytometric analysis revealed that LG treatment resulted in G2/M arrest in cell cycle progression and downregulation of cyclin B1 and CDC2 expression in a concentration-dependent manner. It also resulted in significant upregulation of p27. In addition, LG was seen to trigger the generation of reactive oxygen species and induce CCAAT/enhancer-binding protein homologous protein and 78-kDa glucose-regulated protein in concentration-dependent upregulation. The LG treatment of HN22 cells led to a loss of mitochondrial membrane potential (${\Delta}{\Psi}m$); it also reduced the levels of anti-apoptotic protein and increased the expression of apoptotic protease activating factor-1, cleaved poly (ADP-ribose)polymerase and Bax. Overall, our results indicate that the pro-apoptotic effects of LG in HN22 cells depend on the activation of both intrinsic and extrinsic signaling pathways. Thus, our results suggest that LG constitutes a natural compound with a potential role as an anti-tumor agent in oral squamous cell carcinoma.

• Nutrition Research and Practice
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• v.12 no.6
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• pp.494-502
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• 2018

BACKGROUND/OBJECTIVES: Reducing the number of adipocytes by inducing apoptosis of mature adipocytes as well as suppressing differentiation of preadipocytes plays an important role in preventing obesity. This study examines the anti-adipogenic and pro-apoptotic effect of red pepper seed water extract (RPS) prepared at $4^{\circ}C$ (RPS4) in 3T3-L1 cells. MATERIALS/METHODS: Effect of RPS4 or its fractions on lipid accumulation was determined in 3T3-L1 cells using oil red O (ORO) staining. The expressions of AMP-activated protein kinase (AMPK) and adipogenic associated proteins [peroxisome proliferator-activated receptor-${\gamma}$ ($PPAR-{\gamma}$), CCAAT/enhancer-binding proteins ${\alpha}$ (C/EBP ${\alpha}$), sterol regulatory element binding protein-1c (SREBP-1c), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC)] were measured in 3T3-L1 cells treated with RPS4. Apoptosis and the expression of Akt and Bcl-2 family proteins [B-cell lymphoma 2 (Bcl-2), Bcl-2-associated death promoter (Bad), Bcl-2 like protein 4 (Bax), Bal-2 homologous antagonist/killer (Bak)] were measured in mature 3T3-L1 cells treated with RPS4. RESULTS: Treatment of RPS4 ($0-75{\mu}g/mL$) or its fractions ($0-50{\mu}g/mL$) for 24 h did not have an apparent cytotoxicity on pre and mature 3T3-L1 cells. RPS4 significantly suppressed differentiation and cellular lipid accumulation by increasing the phosphorylation of AMPK and reducing the expression of $PPAR-{\gamma}$, C/EBP ${\alpha}$, SREBP-1c, FAS, and ACC. In addition, all fractions except ethyl acetate fraction significantly suppressed cellular lipid accumulation. RPS4 induced the apoptosis of mature adipocytes by hypophosphorylating Akt, increasing the expression of the pro-apoptotic proteins, Bak, Bax, and Bad, and reducing the expression of the anti-apoptotic proteins, Bcl-2 and p-Bad. CONCLUSIONS: These finding suggest that RPS4 can reduce the numbers as well as the size of adipocytes and might useful for preventing and treating obesity.

• Laboraroty Animal Research
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• v.34 no.4
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• pp.288-294
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• 2018

A few clues about correlation between endoplasmic reticulum (ER) stress and mulberry (Morus alba) leaves were investigated in only the experimental autoimmune myocarditis and streptozotocin-induced diabetes. To investigate whether a novel extract of mulberry leaves fermented with Cordyceps militaris (EMfC) could suppress ER in fatty liver, alterations in the key parameters for ER stress response were measured in high fat diet (HFD)-induced obese C57L/6 mice treated with EMfC for 12 weeks. The area of adipocytes in the liver section were significantly decreased in the HFD+EMfC treated group as compared to the HFD+Vehicle treated group, while their level was higher in HFD+Vehicle treated group than No treated group. The level of the eukaryotic initiation factor 2 alpha ($eIF2{\alpha}$) and inositol-requiring enzyme 1 beta ($IRE1{\alpha}$) phosphorylation and CCAAT-enhancer-binding protein homologous protein (CHOP) expression were remarkably enhanced in the HFD+Vehicle treated group. However, their levels were restored in the HFD+EMfC treated group, although some differences were detected in the decrease rate. Similar recovery was observed on the ER stress-induced apoptosis. The level of Caspase-3, Bcl-2 and Bax were decreased in the HFD+EMfC and HFD+orlistat (OT) treated group compared to the HFD+Vehicle treated group. The results of the present study therefore provide first evidence that EMfC with the anti-obesity effects can be suppressed ER stress and ER stress-induced apoptosis in the hepatic steatosis of HFD-induced obesity model.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.1
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• pp.54-63
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• 2010

Baicalin, a flavonoid, was shown to have diverse effects such as anti-inflammatory, anti-cancer, anti-viral, anti-bacterial and others. Recently, we found that the baicalin inhibits adipogenesis through the modulations of anti-adipogenic and pro-adipogenic factors of the adipogenesis pathway. In the present study, we further characterized the molecular mechanism of the anti-adipogenic effect of baicalin using microarray technology. Microarray analyses were conducted to analyze the gene expression profiles during the differentiation time course (0 day, 2 day, 4 day and 7 day) in 3T3-L1 cells with or without baicalin treatment. We identified a total of 3972 genes of which expressions were changed more than 2 fold. These 3972 genes were further analyzed using hierarchical clustering analysis, resulting in 20 clusters. Four clusters among 20 showed clearly up-regulated expression patterns (cluster 8 and cluster 10) or clearly down-regulated expression patterns (cluster 12 and cluster 14) by baicalin treatment for over-all differentiation period. The cluster 8 and cluster 10 included many genes which enhance cell proliferation or inhibit adipogenesis. On the other hand, the cluster 12 and cluster 14 included many genes which are related with proliferation inhibition, cell cycle arrest, cell growth suppression or adipogenesis induction. In conclusion, these data provide detailed information on the molecular mechanism of baicalin-induced inhibition of adipogenesis.

• Journal of Life Science
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• v.20 no.5
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• pp.729-735
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• 2010

In our previous study, it was reported that an herbal mixture, SH21B, inhibits fat accumulation and adipogenesis both in vitro and in vivo models of obesity. SH21B is a mixture composed of seven herbs: Scutellaria baicalensis Georgi, Prunus armeniaca Maxim, Ephedra sinica Stapf, Acorus gramineus Soland, Typha orientalis Presl, Polygala tenuifolia Willd, and Nelumbo nucifera Gaertner (Ratio 3:3:3:3:3:2:2). The aim of this study was to investigate the detailed molecular mechanisms of the effects of SH21B on various regulators of the adipogenesis pathway. During the adipogenesis of 3T3-L1 cells, SH21B significantly decreased the expression levels of central transcription factors of adipogenesis, such as peroxisome proliferator-activated receptor (PPAR)$\gamma$ and CCAAT/enhancer binding protein (C/EBP)$\alpha$. To elucidate the detailed molecular mechanism of the anti-adipogenic effects of SH21B, we examined the expression levels of the various pro-adipogenic or anti-adipogenic regulators of adipogenesis upstream of $PPAR{\gamma}$ and C/$EBP{\alpha}$. The mRNA levels of Krox20 and Kruppel-like factor (KLF) 15, which are pro-adipogenic regulators, were significantly down-regulated by SH21B treatment, whereas the mRNA levels of C/$EBP{\gamma}$ and KLF5 were not changed. KLF2 and C/EBP homologous protein (CHOP), which are anti-adipogenic regulators, were significantly up-regulated by SH21B treatment. These results suggest that the molecular mechanism of the anti-adipogenic effect of SH21B involves both the down-regulations of pro-adipogenic regulators, such as Krox20 and KLF15, and the up-regulations of anti-adipogenic regulators, such as KLF2 and CHOP, which results in the suppression of central transcription factors of adipogenesis including $PPAR{\gamma}$ and C/$EBP{\alpha}$.