• Asian Pacific Journal of Cancer Prevention
• /
• 제16권13호
• /
• pp.5343-5348
• /
• 2015

Promoter hypermethylation of the runt-related transcription factor 3 (RUNX3) gene is associated with increased risk of hepatocellular carcinoma (HCC). Oxidative stress plays a vital role in both carcinogenesis and progression of HCC. However, whether oxidative stress and RUNX3 hypermethylation in HCC have a cause-and-effect relationship is not known. In this study, plasma protein carbonyl and total antioxidant capacity (TAC) in patients with hepatitis B virus (HBV)-associated HCC (n=60) and age-matched healthy subjects (n=80) was determined. RUNX3 methylation in peripheral blood mononuclear cells (PBMC) of subjects was measured by methylation-specific PCR. Effect of reactive oxygen species (ROS) on induction of RUNX3 hypermethylation in HCC cells was investigated. Plasma protein carbonyl content was significantly higher, whereas plasma TAC was significantly lower, in HCC patients than healthy controls. Based on logistic regression, increased plasma protein carbonyl and decreased plasma TAC were independently associated with increased risk for HCC. PBMC RUNX3 methylation in the patient group was significantly greater than in the healthy group. RUNX3 methylation in hydrogen peroxide ($H_2O_2$)-treated HepG2 cells was significantly higher than in untreated control cells. In conclusion, increase in oxidative stress in Thai patients with HBV-associated HCC was demonstrated. This oxidative increment was independently associated with an increased risk for HCC development. RUNX3 in PBMC was found to be hypermethylated in the HCC patients. In vitro, RUNX3 hypermethylation was experimentally induced by $H_2O_2$. Our findings suggest that oxidative stress is a cause of RUNX3 promoter hypermethylation in HCC cells.

• Journal of Ginseng Research
• /
• 제36권3호
• /
• pp.248-255
• /
• 2012

Potential antioxidant effect of processed ginseng (sun ginseng, SG) on oxidative stress generated by tert-butyl hydroperoxide (t-BHP) was investigated in HepG2 cells. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and lactate dehydrogenase (LDH) leakage test demonstrated that SG dose-dependently prevents a loss of cell viability against t-BHP-induced oxidative stress. Also, SG treatment dose-dependently relieved the increment of activities of hepatic enzymes, such as aspartate aminotrasferase and alanine aminotransferase, and lipid peroxidation mediated by t-BHP treatment in HepG2 cells. SG increased the gene expression of antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase. However, high dose of SG treatment caused decrease in mRNA level of glutathione peroxidase as compared to low dosage of SG-treated cells. The gene expression of glutathione reductase was found to be slightly increased by SG treatment. In addition, SG extract attributed its hepaprotective effect by inducing the mRNA level of bcl-2 and bcl-xL but reducing that of bax. But, the gene expression of bad showed no significant change in SG-treated HepG2 cells. These findings suggest that SG has hepatoprotective effect by showing reduction of LDH release, activities of hepatic enzymes and lipid peroxidation and regulating the gene expression of antioxidant enzymes and apoptosis-related molecules against oxdative stress caused by t-BHP in HepG2 cells.

• Toxicological Research
• /
• 제23권3호
• /
• pp.207-214
• /
• 2007

Chronic oxidative stress produced by exposure to environmental chemicals or pathophysiological states can lead animals to aging, carcinogenesis and degenerative diseases. Indirect antioxidative mechanisms, in which natural or synthetic agents are used to coordinately induce the expression of cellular antioxidant capacity, have been shown to protect cells and organisms from oxidative damages. Electrophile and free radical detoxifying enzymes, which were originally identified as the products of genes induced by cancer chemopreventive agents, are members of this protective system. The NFE2 family transcription factor Nrf2 was found to govern expression of these detoxifying enzymes, and screening for Nrf2-regulated genes has identified many gene categories involved in maintaining cellular redox potential and protection from oxidative damage as Nrf2 downstream genes. Further, studies using Nrf2-deficient mice revealed that these mutant mice showed more susceptible phenotypes towards exposure to environmental chemicals/carcinogens and in oxidative stress related disease models. With the finding that cancer chemopreventive efficacy of indirect antioxidants (enzyme inducers) is lost in the absence of Nrf2, a central role of Nrf2 in the antioxidative protective system has been firmly established. Promising results from cancer prevention clinical trials using enzyme inducers propose that pharmacological interventions that modulate Nrf2 can be an effective strategy to protect tissues from oxidative damage.

• Journal of Microbiology and Biotechnology
• /
• 제34권5호
• /
• pp.1059-1072
• /
• 2024

Oxidative stress is a key factor in the pathogenesis of benign prostatic hyperplasia (BPH) that leads to inflammation. This study aimed to evaluate the ameliorative effects of Salvia miltiorrhiza Bunge extract (HLT-101) on BPH through the regulation of oxidative stress and inflammation. A testosterone propionate (TP)-induced BPH rat model was orally administered HLT-101 (20, 40, or 80 mg/kg), and its effects on oxidative stress- and inflammation-related gene expression were examined. Further, HLT-101 was assessed for its effect on reactive oxygen species (ROS) levels and Nrf-2/HO-1 signaling pathways in BPH-1 cells. HLT-101 decreased testosterone-induced excessive free radical production and inflammatory factor activation. Moreover, HLT-101 treatment significantly decreased the intracellular ROS level in the TNF-α and IFN-γ treated BPH-1 cells through the activation of Nrf-2. In addition, HLT-101 treatment inhibited the NF-κB pathway and androgen receptor (AR) signaling, which is highly linked to the pathogenesis of BPH. Therefore, HLT-101 has the potential to be an effective treatment reagent for BPH because of its ability to reduce inflammation and oxidative stress via Nrf-2/HO-1 signaling.

• 한국환경보건학회지
• /
• 제30권3호
• /
• pp.230-238
• /
• 2004

The adverse health effects of a number of environment pollutions are related to the formation of free radicals. Induction of antioxidant defensive system in the response to an oxidative attack is an essential element of the cell to survive. CYP2E1 is easily induced by organic solvents and induces continuous formation of reactive oxygen species (ROS). ${\gamma}$-Glutamyltranspeptidase (${\gamma}$GT) plays an important role in glutathione metabolism and xenobiotic detoxification. To evaluate the characteristic of oxidative stress which induces GGT expression and to understand human antioxidant defensive response against oxidative stress induced by CYP2E1, we studied regulation of ${\gamma}$GT enzyme expression in response to various oxidative stresses in human HepG2 cells. The ${\gamma}$GT activity was not modified after exposure of acute oxidative stress inducing agents (ferric nitrilotriacetate, cumene hydroperoxide, ADP-Fe, O-tetradecanoylphorbol-13-acetate, tumor necrosis factor-alpha). To induce continuous exposure of cells to ROS, HepG2 cells were transfected by human CYP2E1 gene transiently. The CYP2E1 activity was verified with chlorzoxazone hydroxylation. Transfection of CYP2E1 showed continuous 60% increase in intracellular ROS and 240 % increase in microsomal ROS. CYP2E1 overexpressing cells showed increased ${\gamma}$GT activity (2.5-fold). The observed enhancement of ${\gamma}$GT activity correlated with a significant increase of ${\gamma}$GT mRNA (2.1-fold). Treatment with antioxidant strongly prevented the increase in ${\gamma}$GT activity. The CYP2E1 overexpression did not modify toxicity index and increased glutathione levels. These results show that continuous exposure of cells to ROS produced by CYP2E1 up-regulates ${\gamma}$GT; This may be one of the adaptive antioxidant responses of cells to oxidative insult. Present study also suggests that the induction of ${\gamma}$GT could be used as a marker of oxidative stress induced by exposure to organic solvents.

• The Plant Pathology Journal
• /
• 제27권1호
• /
• pp.89-92
• /
• 2011

Cyclic AMP receptor-like protein (Clp), is known to be a global transcriptional regulator for the expression of virulence factors in Xanthomonas campestris pv. campestris (Xcc). Sequence analysis showed that Xanthomonas oryzae pv. oryzae (Xoo) contains a gene that is strongly homologous to the Xcc clp. In order to determine the role of the Clp homolog in Xoo, a marker exchange mutant of $clp_{xoo4158}$ was generated. Virulence and virulence factors, such as the production of cellulase, xylanase, and extracellular polysaccharides (EPS) and swarming motility were significantly decreased in the $clp_{xoo4158}$ mutant. Moreover, the mutation caused the strain to be more sensitive to hydrogen peroxide and to over-produce siderophores. Complementation of the mutant restored the mutation-related phenotypes. Expression of $clp_{xoo4158}$, assessed by reverse-transcription realtime PCR and clp promoter activity, was significantly reduced in the rpfB, rpfF, rpfC, and rpfG mutants. These results suggest that the clp homolog, $clp_{xoo4158}$, is involved in the control of virulence and resistance against oxidative stress, and that expression of the gene is controlled by RpfC and RpfG through a diffusible signal factor (DSF) signal in Xanthomonas oryzae pv. oryzae KACC10859.

• 대한임상검사과학회지
• /
• 제51권4호
• /
• pp.475-483
• /
• 2019

세포기반 치료제에 사용되는 줄기세포는 재생능력과 다양한 세포로의 분화능력으로 인해 재생 의학 분야에서 광범위하게 관심을 끌었으며, 많은 불치병에 적용된다. 하지만, 이러한 줄기세포는 여전히 치료 전 세포증식 및 질병 투여부위에서의 낮은 생존률로 인해 충분한 치료효과가 나타나지 않는 단점이 있다. 이것을 해결하고자, 우리는 세포부착능과 항세포자살 기능을 가지고 있는 carcinoembryonic antigen (CEA) gene family의 하나인 CEACAM 6를 사용하였다. 이것을 줄기세포에 적용 전, 먼저 세포별로 이 단백질이 발현되는지를 확인하였고, 이 유전자가 발현되는 벡터를 줄기세포에 삽입시키기 위한 최적 조건을 선정하였다. 그 후, 도입된 CEACAM 6발현벡터로부터 줄기세포에서 이 유전자가 발현되는지를 확인하였다. 그리고 인체투여 시 발생되는 산화적 스트레스와 유사한 조건에서의 이 유전자의 기능을 평가하기 위해 과산화수소(H₂O₂)를 처리하였다. 산화적 스트레스 조건하에서 CEACAM 6가 발현되는 줄기세포는 그렇지 않은 세포에 비해 세포의 생존률이 현저히 증가하는 것을 확인하였다. 이를 통해, 이 CEACAM 6는 줄기세포의 치료효능과 세포증식을 강화시킬 수 있는 다른 선택지로서의 가능성이 있음을 확인하였다.

• The Plant Pathology Journal
• /
• 제35권5호
• /
• pp.393-405
• /
• 2019

Survival factor 1 (Svf1) is a protein involved in cell survival pathways. In Saccharomyces cerevisiae, Svf1 is required for the diauxic growth shift and survival under stress conditions. In this study, we characterized the role of FgSvf1, the Svf1 homolog in the homothallic ascomycete fungus Fusarium graminearum. In the FgSvf1 deletion mutant, conidial germination was delayed, vegetative growth was reduced, and pathogenicity was completely abolished. Although the FgSvf1 deletion mutant produced perithecia, the normal maturation of ascospore was dismissed in deletion mutant. The FgSvf1 deletion mutant also showed reduced resistance to osmotic, fungicide, and cold stress and reduced sensitivity to oxidative stress when compared to the wild-type strain. In addition, we showed that FgSvf1 affects glycolysis, which results in the abnormal vegetative growth in the FgSvf1 deletion mutant. Further, intracellular reactive oxygen species (ROS) accumulated in the FgSvf1 deletion mutant, and this accumulated ROS might be related to the reduced sensitivity to oxidative stress and the reduced resistance to cold stress and fungicide stress. Overall, understanding the role of FgSvf1 in F. graminearum provides a new target to control F. graminearum infections in fields.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 2005년도 춘계학술대회
• /
• pp.53-60
• /
• 2005

Parkinson's disease (PD) is a progressive neurodegenerative disorder affecting $1\%$ of the population above the age of 65 and is characterized by a selective loss of dopaminergic neurons in the substantia nigra pars compacta. Although the underlying cause of dopaminergic cell death or the mechanism by which these cells degenerate is still not clearly understood, oxidative stress, mitochondrial dysfunction, and protein misfolding are thought to play important roles in the dopaminergic degeneration in PD. Tetrahydrobiopterin (BH4) is synthesized exclusively in the monoaminergic, including dopaminergic, cells and serves as an endogenous and obligatory cofactor for syntheses of the potential oxidative stressors dopamine and nitric oxide. In addition to its contribution toward the syntheses of these two potentially toxic molecules, BH4 itself can directly generate oxidative stress. BH4 undergoes oxidation during the hydroxylation reaction as well as nonenzymatic autooxidation to produce hydrogen peroxide and superoxide radical. We have previously suggested BH4 as an endogenous molecule responsible for the dopaminergic neurodegeneration. BH4 exerts selective toxicity to dopamine-producing cells via generation of oxidative stress, mitochondrial dysfunction, and apoptosis. BH4 also induces morphological, biochemical, and behavioral characteristics associated with PD in vivo. BH4 as well as enzyme activity and gene expression of GTP cyclohydrolase I, the rate-limiting enzyme in BH4 synthesis pathway, are readily upregulated by cellular changes such as calcium influx and by various stimuli including stress situations. This points to the possibility that cellular availability of BH4 might be increased in aberrant conditions, leading to increased extracellular BH4 subsequent degeneration. The fact that BH4 is specifically and endogenously synthesized in dopaminergic cells, Is readily upregulated, and generates oxidative stress-related cell death provides physical relevance of this molecule as an attractive candidate with which to explain the mechanism of pathogenesis of PD.

• 대한한의학방제학회지
• /
• 제26권3호
• /
• pp.207-221
• /
• 2018

Objectives : Present study investigated hepatoprotective effect of Haegan-jeon extract (HE) and tried to elucidate molecular mechanism involved. According to molecular mechanism, present study optimized herbal composition of HE (op-HE) and compared in vitro and in vivo hepatoprotective effects of op-HE to HE. Methods : For in vitro experiments, HepG2 cells were exposed to arachidonic acid (AA, $10{\mu}M$) and iron ($5{\mu}M$) for inducing oxidative stress. Cell viability, GSH contents, $H_2O_2$ production, mitochondrial membrane potential, immunoblot and reporter gene assay were performed to investigate cytoprotective effects and responsible molecular mechanisms. For in vivo experiments, hepatoprotective effect of HE and op-HE were assessed on $CCl_4-induced$ liver injury mice model. Results : HE pretreatment prevented AA+iron-mediated hepatocytes apoptosis. In addition, AA+iron-induced mitochondrial dysfunction, $H_2O_2$ production, glutathione depletion were reduced by HE pretreatment. In addition, nuclear factor erythroid 2-related factor 2 (Nrf2) phosphorylation, antioxidant response element (ARE)-driven reporter gene activity, and antioxidant genes expression were increased by HE. Based on reporter gene and MTT assays, we found that op-HE consisting three medicinal herbs also significantly increased transactivation of Nrf2 and reduced the AA+iron-mediated cytotoxicity. Moreover, in $CCl_4-induced$ liver injury mice model, HE-op had an ability to ameliorate $CCl_4-mediated$ increases in serum alanine transferase and aspartate aminotransferase activity, hepatic degeneration, inflammatory cell infiltration, and collagen deposition. Hepatoprotective effects of op-HE were comparable to those of HE. Conclusions : Present study suggests that op-HE as well as HE exhibit hepatoprotective effect against oxidative stress-mediated liver injury via Nrf2 activation.