• 생약학회지
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• 제47권1호
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• pp.55-61
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• 2016

Antioxidant effects and nuclear factor E2-related factor-2 (Nrf-2) signal pathway of methanol extract and 4 fractions [n-hexane, methylene chloride, ethyl acetate (EtOAc), and n-butanol fractions] from Petasites japonicus were investigated. The EtOAc fraction showed highest polyphenol and flavonoid contents among other fractions. In addition, EtOAc fraction showed stronger scavenging activity against superoxide anion radical than other fractions. Furthermore, we investigated antioxidants effects of the EtOAc fraction under cellular system using $LLC-PK_1$ cells. The EtOAc fraction dose-dependently increased the antioxidant protein expressions of heme oxygenase 1 (HO-1) and thioredoxin reductase 1 (TrxR1) known to be involved in oxidative stress, through activation of Nrf-2. The treatment of EtOAc fraction ($100{\mu}g/mL$) led to the elevation of the high expression of Nrf-2-dependent factor such as HO-1 and TrxR1. These results indicated that the EtOAc fraction of P. japonicus showed high antioxidant activity by regulation of Nrf-2 signaling pathway.

• Molecules and Cells
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• 제27권3호
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• pp.279-282
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• 2009

"Two-cysteine" peroxiredoxins are antioxidant enzymes that exert a cytoprotective effect in many models of oxidative stress. However, under highly oxidizing conditions they can be inactivated through hyperoxidation of their peroxidatic active site cysteine residue. Sulfiredoxin can reverse this hyperoxidation, thus reactivating peroxiredoxins. Here we review recent investigations that have shed further light on sulfiredoxin's role and regulation. Studies have revealed sulfiredoxin to be a dynamically regulated gene whose transcription is induced by a variety of signals and stimuli. Sulfiredoxin expression is regulated by the transcription factor AP-1, which mediates its up-regulation by synaptic activity in neurons, resulting in protection against oxidative stress. Furthermore, sulfiredoxin has been identified as a new member of the family of genes regulated by Nuclear factor erythroid 2-related factor (Nrf2) via a conserved cis-acting antioxidant response element (ARE). As such, sulfiredoxin is likely to contribute to the net antioxidative effect of small molecule activators of Nrf2. As discussed here, the proximal AP-1 site of the sulfiredoxin promoter is embedded within the ARE, as is common with Nrf2 target genes. Other recent studies have shown that sulfiredoxin induction via Nrf2 may form an important part of the protective response to oxidative stress in the lung, preventing peroxiredoxin hyperoxidation and, in certain cases, subsequent degradation. We illustrate here that sulfiredoxin can be rapidly induced in vivo by administration of CDDO-TFEA, a synthetic triterpenoid inducer of endogenous Nrf2, which may offer a way of reversing peroxiredoxin hyperoxidation in vivo following chronic or acute oxidative stress.

• Asian Pacific Journal of Cancer Prevention
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• 제15권1호
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• pp.299-304
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• 2014

Cholangiocarcinoma (CCA), a malignancy of biliary duct with a very poor prognosis, is the leading cause of cancer death in countries of the Mekong subregion. Liver fluke infection is the main etiological factor, but genetic variation has been recognized as also important in conferring susceptibility to CCA risk. Nuclear factor (erythroid derived 2)-like 2 (NRF2) is a key transcription factor in detoxification and antioxidant defense. Emerging evidence has demonstrated that genetic polymorphisms in the NRF2 gene may be associated with cancer development. The objectives of this study were to investigate the association of NRF2 genetic polymorphism with CCA risk and to evaluate the influence of the NRF2 genotype on survival time of affected patients. Single nucleotide polymorphisms (SNPs) of the NRF2 gene, including rs6726395: A/G, rs2886161: C/T, rs1806649: C/T, and rs10183914: C/T, were analyzed using TaqMan$^{(R)}$ SNP genotyping assays. Among 158 healthy northeastern Thai subjects, the allele frequencies were 41, 62, 94, and 92%, respectively. The correlation of NRF2 SNPs and CCA risk was analyzed in the 158 healthy subjects and 198 CCA patients, using unconditional logistic regression. The results showed that whereas the NRF2 SNPs were not associated with CCA risk (p>0.05), Kaplan-Meier analysis of 88 intrahepatic CCA patients showed median survival time with rs6726395 genotypes of GG and AA/AG to be $344{\pm}138$ (95%CI: 73-615) days and $172{\pm}37$ (95%CI: 100-244) days, respectively, (p<0.006). On multivariate Cox proportional hazard analysis, the GG genotype of rs6726395 was found to be associated with longer survival with a hazard ratio of 0.54 (95%CI: 0.31-0.94). In addition, non-papillary adenocarcinoma was associated with poor survival with a hazard ratio of 2.09 (95%CI: 1.16-3.75). The results suggest that the NRF2 rs6726395 polymorphism can be a potential prognostic biomarker for CCA patients.

• Archives of Pharmacal Research
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• 제27권7호
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• pp.757-762
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• 2004

The protective adaptive response to electrophiles and reactive oxygen species is mediated by the induction of phase II detoxifying genes including glutathione S-transferases (GSTs). NF-E2-related factor-2 (Nrf2) phosphorylation by protein kinase C (PKC) is a critical event for its nuclear translocation in response to oxidative stress. Previously, we have shown that peroxynitrite plays a role in activation of Nrf2 and Nrf2 binding to the antioxidant response element (ARE) via the pathway of phosphatidylinositol 3-kinase (PI3-kinase) and that nitric oxide synthase in hepatocytes is required for GSTA2 induction. In view of the importance of PKC and Pl3-kinase in Nrf2-mediated GST induction, we investigated the role of these kinases in peroxynitrite formation for GSTA2 induction by oxidative stress and determined the relationship between PKC and PI3-kinase. Although PKC activation by phorbol 12-myristate-13-acetate (PMA) did not increase the extents of constitutive and inducible GSTA2 expression, either PKC depletion by PMA or PKC inhibition by staurosporine significantly inhibited GSTA2 induction by tert-butylhydroquinone (t-SHa) a prooxidant chemical. Therefore, the basal PKC activity is req- uisite for GSTA2 induction. 3-Morpholinosydnonimine (SIN-1), which decomposes and yields peroxynitrite, induced GSTA2, which was not inhibited by PKC depletion, but slightly enhanced by PKC activation, suggesting that PKC promotes peroxynitrite formation for Nrf2-mediated GSTA2 induction. Treatment of cells with S-nitroso-N-acetyl-penicillamine (SNAP), an exogenous NO donor, in combination with t-BHQ may produce peroxynitrite. GSTA2 induction by SNAP ＋ t-BHQ was not decreased by PKC depletion, but rather enhanced by PKC activation, showing that the activity of PKC might be required for peroxynitrite formation. LY294002 a P13-kinase inhibitor blocked GSTA2 induction by t-BHQ, which was reversed by PMA-induced PKC activation. These results provide evidence that PKC may playa role in formation of peroxynitrite that activates Nrf2 for GSTA2 induction and that PKC may serve an activator for GSTA2 induction downstream of PI3-kinase.

• Food Science and Biotechnology
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• 제17권2호
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• pp.367-372
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• 2008

Cellular protection against carcinogens could be achieved by the induction of phase 2 detoxifying and antioxidant enzymes such as glutathione S-transferase (GST), NAD(P)H:quinone oxidoreductase 1 (NQO1) and heme oxygenase 1 (HO1). Nuclear transcription factor E2-related factor 2 (Nrf2) binds to antioxidant response element (ARE) in the promoter region of these genes and the resulting transactivation occurs. In the present study the effect of gujeolcho (Chrysanthemum zawadskii) roots on the Nrf2-ARE pathway were investigated. C. zawadskii root extract was fractionated with a series of organic solvents and their ability to induce Nrf2-ARE pathway was examined. We separated the most potent dichloromethane (DCM) fraction into 12 sub-fractions and found several sub-fractions with strong effects on the Nrf2-ARE pathway. Fraction 4 strongly induced the ARE-reporter gene activity as well as Nrf2 expression. Sitosterol was isolated as a major compound in fraction 4 although its activity was not as potent as its mother fraction. These results indicate that C. zawadskii roots might be used as a potential natural chemopreventive source.

• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2317-2320
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• 2013

Thiourea and vinyl sulfoxide derivatives were designed based on the structures of sulforaphane and gallic acid, prepared and tested for HO-1 inducing activity as a measure of Nrf2 activation, and inhibitory effect on NO production as a measure of anti-inflammatory activity. Both series of compounds showed moderate activity on HO-1 induction, and no inhibitory effect on NO production. Interestingly the thiourea compound 6d showed better HO-1 induction (71% SFN) than the corresponding isothiocyanate compound 6a (55% SFN). Overall, it seemed that more efficient electrophile is needed to get more effective Nrf2 activator.

• Asian Pacific Journal of Cancer Prevention
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• 제17권11호
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• pp.4945-4949
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• 2016

Background: Breast cancer is the commonest cancer in Egyptian females. Nrf2 is involved in oxidative stress while P73 functions in response to DNA damage. This study aimed to assess the role of Nrf2 promoter and P73 G4C14 to A4T14 SNPs in breast cancer in Egypt. Patients: Eighty-five female patients with breast tumours (41 malignant, 44 benign) were included. Nrf2 (rs6721961) and p73 (G4A) SNPs were determined by PCR- CTPP assay. Results: Genotype frequencies of the Nrf2 promoter SNP were 34.2% and 37.9% for AA in benign and malignant groups respectively, and 43.9% and 40.5% for CC and, 21.9 % and 21.6% for CA. Genotype frequencies for the P73 G4A SNP were 52.9% and 44.7% for GA in benign and malignant groups respectively, and 47.1% and 55.3% for GG. Discussion: Nrf2 genotypes in pre - and post-menopausal patients, showed significantly different distributions in the 2 patient groups, the AA genotype being significantly more common in pre-menopausal patients. The P73 G4A SNP showed no relation to age of disease onset. Conclusion: The Nrf2 (rs6721961) AA genotype might be related to early breast cancer onset. In contrast the P73 G4A polymorphism showed no relation to either disease risk or age at presentation.

• 치위생과학회지
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• 제19권3호
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• pp.198-204
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• 2019

Background: Oxidative stress is a known to be associated with in the pathogenesis of many inflammatory diseases, including periodontitis. Ursolic acid is a pentacyclic triterpenoid with has antimicrobial, antioxidative, and anticancer properties. However, the role of ursolic acid in the regulating of osteogenesis remains undetermined. This study was aimed to elucidate the crucial osteogenic effects of ursolic acid and its ability to inhibit oxidative stress by targeting the immediate early response 3 (IER3)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Methods: Cell proliferation was determined using water-soluble tetrazolium salt assay, cell differentiation was evaluated by alkaline phosphatase (ALP) activity, and formation of calcium nodules was detected using alizarin red S stain. Generation of reactive oxygen species (ROS) was determined using by DCFH-DA fluorescence dye in hydrogen peroxide ($H_2O_2$)-treated MG-63 cells. Expression levels of IER3, Nrf2, and heme oxygenase-1 (HO-1) were analyzed using western blot analysis. Results: Our results showed that ursolic acid up-regulated the proliferation of osteoblasts without any cytotoxic effects, and promoted ALP activity and mineralization. $H_2O_2$-induced ROS generation was found to be significantly inhibited on treatment with ursolic acid. Furthermore, in $H_2O_2$-treated cells, the expression of the early response genes: IER3, Nrf2, and Nrf2-related phase II enzyme (HO-1) was enhanced in the presence of ursolic acid. Conclusion: The key findings of the present study elucidate the protective effects of ursolic acid against oxidative stress conditions in osteoblasts via the IER3/Nrf2 pathway. Thus, ursolic acid may be developed as a preventative and therapeutic agent for mineral homeostasis and inflammatory diseases caused due to oxidative injury.

• Molecules and Cells
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• 제41권12호
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• pp.1008-1015
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• 2018

$I{\kappa}B$, a cytoplasmic inhibitor of nuclear factor-${\kappa}B$ ($NF-{\kappa}B$), is reportedly degraded via the proteasome. However, we recently found that long-term incubation with proteasome inhibitors (PIs) such as PS-341 or MG132 induces $I{\kappa}B{\alpha}$ degradation via an alternative pathway, lysosome, which results in $NF-{\kappa}B$ activation and confers resistance to PI-induced lung cancer cell death. To enhance the anti-cancer efficacy of PIs, elucidation of the regulatory mechanism of PI-induced $I{\kappa}B{\alpha}$ degradation is necessary. Here, we demonstrated that PI up-regulates nuclear factor (erythroid-derived 2)-like 2 (Nrf2) via both de novo protein synthesis and Kelch-like ECH-associated protein 1 (KEAP1) degradation, which is responsible for $I{\kappa}B{\alpha}$ degradation via macroautophagy activation. PIs increased the protein level of light chain 3B (LC3B, macroautophagy marker), but not lysosome-associated membrane protein 2a (Lamp2a, the receptor for chaperone-mediated autophagy) in NCI-H157 and A549 lung cancer cells. Pretreatment with macroautophagy inhibitor or knock-down of LC3B blocked PI-induced $I{\kappa}B{\alpha}$ degradation. PIs up-regulated Nrf2 by increasing its transcription and mediating degradation of KEAP1 (cytoplasmic inhibitor of Nrf2). Overexpression of dominant-negative Nrf2, which lacks an N-terminal transactivating domain, or knock-down of Nrf2 suppressed PI-induced LC3B protein expression and subsequent $I{\kappa}B{\alpha}$ degradation. Thus, blocking of the Nrf2 pathway enhanced PI-induced cell death. These findings suggest that Nrf2-driven induction of LC3B plays an essential role in PI-induced activation of the $I{\kappa}B$/$NF-{\kappa}B$ pathway, which attenuates the anti-tumor efficacy of PIs.

• Journal of Ginseng Research
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• 제47권1호
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• pp.106-116
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• 2023

Background: Pirarubicin (THP) is an anthracycline antibiotic used to treat various malignancies in humans. The clinical usefulness of THP is unfortunately limited by its dose-related cardiotoxicity. Ginsenoside F1 (GF1) is a metabolite formed when the ginsenosides Re and Rg1 are hydrolyzed. However, the protective effects and underlying mechanisms of GF1 on THP-induced cardiotoxicity remain unclear. Methods: We investigated the anti-apoptotic and anti-oxidative stress effects of GF1 on an in vitro model, using H9c2 cells stimulated by THP, plus trigonelline or AKT inhibitor imidazoquinoxaline (IMQ), as well as an in vivo model using THP-induced cardiotoxicity in rats. Using an enzyme-linked immunosorbent test, the levels of malondialdehyde (MDA), brain natriuretic peptide (BNP), creatine kinase (CK-MB), cardiac troponin (c-TnT), lactate dehydrogenase (LDH), superoxide dismutase (SOD) and glutathione (GSH) were determined. Nuclear factor (erythroid-derived2)-like 2 (Nrf2) and the expression of Nrf2 target genes, including heme oxygenase-1 (HO-1), glutathione-S-transferase (Gst), glutamate-cysteine ligase modifier subunit (GCLM), and expression levels of AKT/Bcl-2 signaling pathway proteins were detected using Western blot analysis. Results: THP-induced myocardial histopathological damage, electrocardiogram (ECG) abnormalities, and cardiac dysfunction were reduced in vivo by GF1. GF1 also decreased MDA, BNP, CK-MB, c-TnT, and LDH levels in the serum, while raising SOD and GSH levels. GF1 boosted Nrf2 nuclear translocation and Nrf2 target gene expression, including HO-1, Gst, and GCLM. Furthermore, GF1 regulated apoptosis by activating AKT/Bcl-2 signaling pathways. Employing Nrf2 inhibitor trigonelline and AKT inhibitor IMQ revealed that GF1 lacked antioxidant and anti-apoptotic effects. Conclusion: In conclusion, GF1 was found to alleviate THP-induced cardiotoxicity via modulating Nrf2 and AKT/Bcl-2 signaling pathways, ultimately alleviating myocardial oxidative stress and apoptosis.