• Korean Journal of Veterinary Research
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• v.56 no.1
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• pp.15-21
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• 2016

NAD(P)H-quinone oxidoreductase-1 (NQO1) is a down-stream target gene of nuclear factor erythroid 2-related factor 2 (Nrf2), and performs diverse biological functions. Recently, NQO1 is recognized as an effective gene for the cytotoxic inserts with its diverse biological functions, which is focused on antioxidant properties. The aim of present study was to assess the impact of NQO1 knockdown on cytoprotection-related protein expression in cisplatin cytotoxicity by using small interfering (si) RNA targeted on NQO1 gene. Cytotoxicity of cisplatin on ACHN cells was assessed in a dose- and time-dependent manner after siScramble or siNQO1 treatment. After cisplatin treatment, cells were subjected to cell viability assay, western-blot analysis, and immunofluorescence study. The cell viability was decreased in the siNQO1 cells (50%) than the siScramble cells (70%) after 24 h of cisplatin ($20{\mu}M$) treatment. Moreover, cytoprotection-related protein expressions were markedly suppressed in the siNQO1 cells after cisplatin treatment. The expression of Nrf2 and Klotho were decreased by 20% and 40%, respectively, of that in siScramble cells. Nrf2 and Klotho activation were also decreased in cisplatin treated siNQO1 cells, confirmed by cytoplasm-tonuclear translocation. Our findings demonstrate that the increased cisplatin-induced cytotoxicity was accompanied by suppressed Nrf2 activation and Klotho expression in siNQO1 cells.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3623-3626
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• 2014

Nuclear factor-erythroid 2-related factor 2 (Nrf2) regulates the expression of over 200 genes of antioxidant and phase II drug-metabolizing enzymes, and is highly expressed in non-small cell lung cancer (NSCLC). Nine derivatives of 4-(2-cyclohexylethoxy)aniline were designed. Our previous study demonstrated that IM3829 increases radiosensitivity of several lung cancer cells in vitro and in vivo. Here, biological effects of IM3829 derivatives (2a-2i) were evaluated. Compound 2g derivative effectively inhibits mRNA and protein expression of Nrf2 and HO-1. In addition, we observed over two fold enhancement in IR-induced cell death, from $2.90{\pm}0.22$ to $6.02{\pm}0.87$, in H1299 cancer cell-line. Among the nine derivatives, compound 2g derivative exhibited the highest enhancement of radiosensitizing effect via inhibition of Nrf2 activity.

• BMB Reports
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• v.50 no.11
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• pp.560-565
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• 2017

Geraniin, a hydrolysable tannin, used in traditional medicine in Southeast Asia, is known to exhibit various biological activities. As an antioxidant it is known to up-regulate phase II enzyme Heme oxygenase-1 (HO-1). However its mechanism is not clearly understood. Nuclear factor erythroid-derived 2 related factor 2 (Nrf-2) is transcriptionally up-regulated by Extracellular signal-regulated kinase (ERK) 1/2 and retained in nucleus due to inactivated Glycogen synthase kinase 3 beta ($GSK-3{\beta}$). Geraniin additionally down-regulates expression of microRNA 217 and 377 (miR-217 and miR-377) which target HO-1 mRNA. Expression of BTB and CNC homolog 1 (BACH-1), another regulator of HO-1, is also down-regulated by up-regulating microRNA 98 (miR-98), a negative regulator of BACH-1. Thus, geraniin up-regulates HO-1 expression both through activating its positive regulator Nrf-2 and by down-regulating its negative regulator BACH-1. Up-regulation of HO-1 also confers protection to HepG2 cells from tertiary butyl hydroperoxide (TBH) induced cytotoxicity.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.5
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• pp.373-384
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• 2020

Paeonol, quercetin, β-sitosterol, and gallic acid extracted from Moutan Cortex had been reported to possess anti-oxidative, anti-inflammatory, and anti-tumor activities. This work aimed to illustrate the potential anti-oxidative mechanism of monomers in human liver hepatocellular carcinoma (HepG2) cells-induced by hydrogen peroxide (H₂O₂) and to evaluate whether the hepatoprotective effect of monomers was independence or synergy in mice stimulated by carbon tetrachloride (CCl₄). Monomers protected against oxidative stress in HepG2 cells in a dose-response manner by inhibiting the generation of reactive oxygen species, increasing total antioxidant capacity, catalase and superoxide dismutase (SOD) activities, and activating the antioxidative pathway of nuclear factor E2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) signaling pathway. We found that the in vitro antioxidant capacities of paeonol and quercetin were better than those of β-sitosterol and gallic acid. Furthermore, paeonol apparently diminished the levels of alanine transaminase and aspartate aminotransferase, augmented the contents of glutathione and SOD, promoted the expressions of Nrf2 and heme oxygenase-1 proteins in mice stimulated by CCl₄. In HepG2 cells, paeonol, quercetin, β-sitosterol, and gallic acid play a defensive role against H₂O₂-induced oxidative stress through activating Nrf2/Keap1 pathway, indicating that these monomers have anti-oxidative properties. Totally, paeonol and quercetin exerted anti-oxidative and hepatoprotective effects, which is independent rather than synergy.

• Journal of Ginseng Research
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• v.47 no.2
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• pp.311-318
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• 2023

Background: The beneficial effects of compound K (CK) on different chronic diseases have been shown to be at least related to antioxidant action. Nevertheless, since its antioxidant activity in human retinal pigment epithelial (RPE) cells is still unknown, here we investigated whether CK alleviates oxidative stress-stimulated damage in RPE ARPE-19 cells. Methods: The cytoprotective consequence of CK in hydrogen peroxide (H₂O₂)-treated cells was evaluated by cell viability, DNA damage, and apoptosis assays. Fluorescence analysis and immunoblotting were performed to investigate the inhibitory action of CK on reactive oxygen species (ROS) production and mitochondrial dysfunction. Results: H₂O₂-promoted cytotoxicity, oxidative stress, DNA damage, mitochondrial impairment, and apoptosis were significantly attenuated by CK in ARPE-19 cells. Furthermore, nuclear factor erythroid 2-related factor 2 (Nrf2) phosphorylation level and its shuttling to the nucleus were increased, which was correlated with upregulated activation of heme oxygenase-1 (HO-1). However, zinc protoporphyrin, a blocker of HO-1, significantly abrogated the preventive action of CK in H₂O₂-treated ARPE-19 cells. Conclusion: This study indicates that activation of Nrf2/HO-1 signaling by CK plays an important role in rescuing ARPE-19 cells from oxidative cellular damage.

• Journal of Microbiology and Biotechnology
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• v.34 no.3
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• pp.596-605
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• 2024

Anthocyanins belong to phenolic pigments and are known to have various pharmacological activities. This study aimed to investigate whether anthocyanins could inhibit hydrogen peroxide (H₂O₂)-induced oxidative damage in human retinal pigment epithelial ARPE-19 cells. Our results indicated that anthocyanins suppressed H₂O₂-induced genotoxicity, while inhibiting reactive oxygen species (ROS) production and preserving diminished glutathione. Anthocyanins also suppressed H₂O₂-induced apoptosis by reversing the Bcl-2/Bax ratio and inhibiting caspase-3 activation. Additionally, anthocyanins attenuated the release of cytochrome c into the cytosol, which was achieved by interfering with mitochondrial membrane disruption. Moreover, anthocyanins increased the expression of heme oxygenase-1 (HO-1) as well as its activity, which was correlated with the phosphorylation and nuclear translocation of nuclear factor-erythroid-2 related factor 2 (Nrf2). However, the cytoprotective and anti-apoptotic effects of anthocyanins were significantly attenuated by the HO-1 inhibitor, demonstrating that anthocyanins promoted Nrf2-induced HO-1 activity to prevent ARPE-19 cells from oxidative stress. Therefore, our findings suggest that anthocyanins, as Nrf2 activators, have potent ROS scavenging activity and may have the potential to protect ocular injury caused by oxidative stress.

• Herbal Formula Science
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• v.16 no.2
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• pp.193-204
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• 2008

Dehydrocostus lactone (DHL) and Mokko lactone (ML) were isolated from Saussureae Radix, and their effects on heme oxygenase-1 (HO-1) expression and hepatoprotection in the liver cell line HepG2 were investigated. DHL induced HO-1 expression and HO activity in a dose-dependent manner, whereas ML lacking one double bond property at 11 and 13 carbons on its own chemical structure had no apparent effects. DHL also induced Nrf2 nuclear translocation and enhanced antioxidant response element (ARE) activation which mediated HO-1 gene transcription. Pretreatment with DHL protected HepG2 cells against oxidative damages caused by H2O2. Interestingly, the hepatoprotective effects of DHL appeared to be associated with HO enzymatic activation, HO-1 expression and Nrf2 activation, because blockage of HO activity by a HO inhibitor and inhibition of HO-1 and Nrf2 cellular synthesis by small interfering RNA abolished heptoprotection afforded by DHL. Taken together, this investigation provides evidence supporting that Saussureae Radix is hepatoprotective against oxidative stress that causes abnormal liver damages.

• Molecules and Cells
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• v.42 no.10
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• pp.702-710
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• 2019

Neuroinflammation is an important contributor to the pathogenesis of neurodegenerative disorders including Parkinson's disease (PD). We previously reported that our novel synthetic compound KMS99220 has a good pharmacokinetic profile, enters the brain, exerts neuroprotective effect, and inhibits $NF{\kappa}B$ activation. To further assess the utility of KMS99220 as a potential therapeutic agent for PD, we tested whether KMS99220 exerts an anti-inflammatory effect in vivo and examined the molecular mechanism mediating this phenomenon. In 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mice, oral administration of KMS99220 attenuated microglial activation and decreased the levels of inducible nitric oxide synthase and interleukin 1 beta ($IL-1{\beta}$) in the nigrostriatal system. In lipopolysaccharide (LPS)-challenged BV-2 microglial cells, KMS99220 suppressed the production and expression of $IL-1{\beta}$. In the activated microglia, KMS99220 reduced the phosphorylation of $I{\kappa}B$ kinase, c-Jun N-terminal kinase, and p38 MAP kinase; this effect was mediated by heme oxygenase-1 (HO-1), as both gene silencing and pharmacological inhibition of HO-1 abolished the effect of KMS99220. KMS99220 induced nuclear translocation of the transcription factor Nrf2 and expression of the Nrf2 target genes including HO-1. Together with our earlier findings, our current results show that KMS99220 may be a potential therapeutic agent for neuroinflammation-related neurodegenerative diseases such as PD.

• Journal of Life Science
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• v.21 no.7
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• pp.1046-1051
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• 2011

Diallyl disulfide (DADS), the most prevalent oil-soluble organosulfur compound in garlic, is known to have diverse biological activities, including anticarcinogenic, antiatherosclerotic, antiinflammatory, and antioxidant actions. In this study, we investigated the effect of DADS on the expression of heme oxygenase-1 (HO-1) in human liver hepatoma cell line HepG2. Treatment of HepG2 cells by DADS evoked a dose-dependent growth inhibition without significant toxicity to the cells, and also induced the expression of transcription factor Nrf2. However, DADS did not have any enhancing effect on transcription and translation of HO-1 expression in HepG2 cells. In addition, DADS efficiently blocked protein synthesis of HO-1 in HepG2 cells stimulated by CoPP or hemin. But, DADS did not decrease the content of transcripts of HO-1 gene stimulated by CoPP, with accumulation of Nrf2 and small Maf in the nucleus. Based on these results, we conclude that DADS inhibits HO-1 expression by modulation of translational level of CoPP or hemin-induced HO-1 expression in HepG2 cells.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.180-180
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• 2003

Peroxisome proliferator-activated receptor gamma (PPAR-gamma), a member of the nuclear hormone receptor superfamily, is involved in the suppression of growth of several types of tumors such as liposarcoma, cancers of breast, prostate, and colon, possibly through induction of cell cycle arrest and/or apoptosis.(omitted)