Induction of Cell Cycle Arrest and Apoptosis in Human Osteosarcoma U-2 OS Cells by Solanum lyratum Extracts

This research focused on a Chinese herb medicine, Solanum lyratum Thunb (Solanaceae) by ethanol extracts (SLE) for investigating the molecular anticancer mechanism in vitro for exploring the means of cell death through the effects on mitochondrial function. We found that SLE induced cytotoxic effects in human osteosacroma U-2 OS cells, and these effects include cell morphological changes, a decrease of the percentage of viable cells and induction of apoptosis. The results suggest that cell death induced by SLE is closely related to apoptosis based on the observations of DAPI staining and sub-G1 phase in U-2 OS cells. Flow cytometric assays also showed that SLE promoted the production of reactive oxygen species and nitric oxide but decreased the levels of mitochondrial membrane potential and promoted the activations of caspase-8 and -9 in U-2 OS cells. SLE inhibited the level of Bcl-2 but promoted the Bax level, and both proteins led to the release of cytochrome c from mitochondria to cytosol and activation of caspase-9 and -3, resulting in the apoptotic death which is mediated through the mitochondrial pathway. Taken together, SLE was demonstrated to be effective in killing U-2 OS osteosacroma cells via the ROS-promoted and mitochondria- and caspase-dependent apoptotic pathways.     

Black rice extract protected HepG2 cells from oxidative stress-induced cell death via ERK1/2 and Akt activation

BACKGROUND/OBJECTIVES

The objective of this study was to evaluate the protective effect of black rice extract (BRE) on tert-butyl hydroperoxide (TBHP)-induced oxidative injury in HepG2 cells.

MATERIALS/METHODS

Methanolic extract from black rice was evaluated for the protective effect on TBHP-induced oxidative injury in HepG2 cells. Several biomarkers that modulate cell survival and death including reactive oxygen species (ROS), caspase-3 activity, and related cellular kinases were determined.

RESULTS

TBHP induced cell death and apoptosis by a rapid increase in ROS generation and caspase-3 activity. Moreover, TBHP-induced oxidative stress resulted in a transient ERK1/2 activation and a sustained increase of JNK1/2 activation. While, BRE pretreatment protects the cells against oxidative stress by reducing cell death, caspase-3 activity, and ROS generation and also by preventing ERKs deactivation and the prolonged JNKs activation. Moreover, pretreatment of BRE increased the activation of ERKs and Akt which are pro-survival signal proteins. However, this effect was blunted in the presence of ERKs and Akt inhibitors.

CONCLUSIONS

These results suggest that activation of ERKs and Akt pathway might be involved in the cytoprotective effect of BRE against oxidative stress. Our findings provide new insights into the cytoprotective effects and its possible mechanism of black rice against oxidative stress.     

Antiproliferation of melanoma cells by polysaccharide isolated from Zizyphus jujuba

Objective

Zizyphus jujuba, a traditional Chinese herb rich in functional components such as polysaccharide, has been widely consumed in Asian countries. The objective of this study was to determine the antiproliferation effect of melanoma cells as affected by deproteinized polysaccharide (DPP) isolated from Z. jujuba.

Methods

Deproteinized polysaccharide was obtained through boiling water extraction, ethanol precipitation, deproteinization, and dialysis, and the molecular weight of DPP was determined by high-performance gel-filtration chromatography. Melanoma cell viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, the cell cycle was analyzed by flow cytometry, the formation of apoptotic bodies was observed under a fluorescence microscope at 450 nm, and caspase-3 and caspase-9 were measured by an assay kit.

Results

Deproteinized polysaccharide was composed of two fractions with average molecular weights of 143 108 and 67 633 Da. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test showed that the antiproliferation effect of DPP on melanoma cells followed a dose- and time-dependent course. The 50% inhibitory concentration of DPP in inhibiting melanoma cell growth was 3.99 ± 0.10 mg/mL after 24-h treatment but decreased significantly to 3.36 ± 0.14 mg/mL after 48 h. The cell cycle assay revealed melanoma cells to be arrested in G2/M phase. Moreover, with DPP treatment, the apoptotic bodies were generated, accompanied by an increase in caspase-3 and caspase-9 activity.

Conclusions

This outcome suggested that DPP may be used as a potential anti-skin cancer agent for further in vivo and clinical trial experiments.     

Role of Caspase-8 Activation in Mediating Vitamin E-Induced Apoptosis in Murine Mammary Cancer Cells

The vitamin E family of compounds is divided into two subgroups, tocopherols and tocotrienols. However, tocotrienols display more potent apoptotic activity in mammary cancer cells. Although the mechanism(s) mediating tocotrienol-induced apoptosis is presently unknown, apoptosis is carried out by activation of initiator caspases (caspase-8 or -9) that subsequently activate effector caspases (caspase-3, -6, or -7). Studies were conducted to determine whether tocotrienol-induced apoptosis is mediated by activation of the caspase-8 and/or caspase-9 pathway. Highly malignant +SA mouse mammary epithelial cells were grown in culture and maintained on serum-free media. Treatment with tocotrienol-rich-fraction of palm oil (TRF) and γ-tocotrienol, but not α-tocopherol, induced a dose-dependent decrease in +SA cell viability. TRF- and γ-tocotrienol-induced cell death resulted from apoptosis, as determined by DNA fragmentation and positive TUNEL assay staining. Additional studies showed that treatment with 50 μM TRF or 20 μM γ-tocotrienol increased intracellular activity and levels of processed caspase-8 and -3 but not caspase-9. Furthermore, treatment with specific caspase-8 or -3 inhibitors, but not caspase-9 inhibitor, completely blocked the tocotrienol-induced apoptosis in +SA cells. These findings demonstrate that tocotrienol-induced apoptosis in +SA mammary cancer cells is mediated through activation of the caspase-8 signaling pathway and is independent of caspase-9 activation.     

Role of caspase-8 activation in mediating vitamin E-induced apoptosis in murine mammary cancer cells

The vitamin E family of compounds is divided into two subgroups, tocopherols and tocotrienols. However, tocotrienols display more potent apoptotic activity in mammary cancer cells. Although the mechanism(s) mediating tocotrienol-induced apoptosis is presently unknown, apoptosis is carried out by activation of initiator caspases (caspase-8 or -9) that subsequently activate effector caspases (caspase-3, -6, or -7). Studies were conducted to determine whether tocotrienol-induced apoptosis is mediated by activation of the caspase-8 and/or caspase-9 pathway. Highly malignant +SA mouse mammary epithelial cells were grown in culture and maintained on serum-free media. Treatment with tocotrienol-rich-fraction of palm oil (TRF) and g-tocotrienol, but not a-tocopherol, induced a dose-dependent decrease in +SA cell viability. TRF- and g-tocotrienol-induced cell death resulted from apoptosis, as determined by DNA fragmentation and positive TUNEL assay staining. Additional studies showed that treatment with 50 mM TRF or 20 mM g-tocotrienol increased intracellular activity and levels of processed caspase-8 and -3 but not caspase-9. Furthermore, treatment with specific caspase-8 or -3 inhibitors, but not caspase-9 inhibitor, completely blocked the tocotrienol-induced apoptosis in +SA cells. These findings demonstrate that tocotrienol-induced apoptosis in +SA mammary cancer cells is mediated through activation of the caspase-8 signaling pathway and is independent of caspase-9 activation.     

Intracellular mechanisms mediating tocotrienol-induced apoptosis in neoplastic mammary epithelial cells

Tocotrienols and tocopherols represent the two subgroups that make up the vitamin E family of compounds. However, tocotrienols display significantly more potent apoptotic activity in neoplastic mammary epithelial cells than tocopherols. Studies were conducted to determine the intracellular mechanism(s) mediating tocotrienol-induced apoptosis in neoplastic +SA mouse mammary epithelial cells in vitro. An initial step in apoptosis is the activation of 'initiator' caspases (caspase-8 or -9) that subsequently activate 'effector' caspases (caspase-3, -6 and -7) and induce apoptosis. Treatment with cytotoxic doses of alpha-tocotrienol (20 microM) resulted in a time-dependent increase in caspase-8 and caspase-3 activity. Combined treatment with specific caspase-8 or caspase-3 inhibitors completely blocked alpha-tocotrienol-induced apoptosis and caspase-8 or caspase-3 activity, respectively. In contrast, alpha-tocotrienol treatment had no effect on caspase-9 activation, and combined treatment with a specific caspase-9 inhibitor did not block alpha-tocotrienol-induced apoptosis in (+)SA cells. Since caspase-8 activation is associated with the activation of death receptors, such as Fas, tumor necrosis factor (TNF), or TNF-related apoptosis-inducing ligand (TRAIL) receptors, studies were conducted to determine the exact death receptor(s) and ligand(s) involved in mediating tocotrienol-induced caspase-8 activation and apoptosis. Treatment with Fas-ligand (FasL), Fas-activating antibody, or TRAIL failed to induce cell death in (+)SA neoplastic mammary epithelial cells, suggesting that these cells are resistant to death receptor-induced apoptosis. Moreover, treatment with cytotoxic doses of alpha-tocotrienol did not alter the intracellular levels of Fas, FasL, or Fas-associated death domain (FADD) in these cells. Western blot analysis also showed that alpha-tocotrienol did not induce FasL or FADD translocation from the cytosolic to membrane fraction in these cells. Finally, treatment with Fas-blocking antibody did not reverse the tocotrienol-induced apoptosis in (+)SA cells. These data demonstrate that tocotrienol-induced caspase-8 activation and apoptosis is not mediated through death receptor activation in malignant (+)SA mammary epithelial cells. Resistance to death receptor-induced apoptosis has been shown to be associated with increased expression of apoptosis-inhibitory proteins, such as FLICE-inhibitory protein (FLIP), and enhanced signalling of the phosphatidylinositol 3-kinase (PI3K)/PI3K-dependent kinase (PDK)/Akt mitogenic pathway. Additional studies showed that treatment with cytotoxic doses of alpha-tocotrienol decreased total, membrane, and cytosolic levels of FLIP, and reduced phosphorylated PDK-1 (active) and phosphorylated-Akt (active) levels in these cells. In summary, these findings demonstrate that tocotrienol-induced caspase-8 activation and apoptosis in malignant (+)SA mammary epithelial cells is not mediated through the activation of death receptors, but appears to result from the suppression of the PI3K/PDK/Akt mitogenic signalling pathway, and subsequent reduction in intracellular FLIP expression.     

Effect of Aged Garlic Extract on Caspase-3 Activity,In Vitro

Abstract

In neurodegeneration, such as Alzheimer's disease (AD), apoptosis results in the loss of valuable neurons. A key mechanism in apoptosis is the activation of caspase-3. Caspase-3 activity first becomes detectable early in apoptosis, continues to increase as cells undergo apoptosis, and rapidly declines in late stages of apoptosis. Its activity is an early marker of cells undergoing apoptosis. Caspase-3 catalyzes the formation of β-amyloid peptide, a hallmark of AD. The purpose of the study was to determine whether dietary aged garlic extract (AGE), with known antioxidant properties and neuroprotection against Alzheimer's β-amyloid cytotoxicity, inhibits the caspase-3 activity in vitro. Caspase-3 activity was assayed according to the prescribed protocol and incubated overnight at ambient temperature. We report that AGE inhibits caspase-3 in dose dependent manner. Caspase-8 was not inhibited by AGE. As a caspase-3 inhibitor, AGE may be effective in reducing apoptotic death of neurons since caspase inhibitors have been shown to inhibit neuronal cell death. We propose a scheme for the ameliorative effect of AGE on deleterious effects of β-amyloid and possibly uncontrolled caspase-3 activity.     

Latex of Euphorbia Antiquorum Induces Apoptosis in Human Cervical Cancer Cells via c-Jun N-terminal Kinase Activation and Reactive Oxygen Species Production

Latex of Euphorbia antiquorum (EA) has inhibitory effects on several different cancer cell lines. However, the molecular mechanism of EA inhibitory effects on human cervical cancer HeLa cell growth has not been explored. EA induced apoptosis, which was characterized by morphological change, DNA fragmentation, increased sub-G1 population, and alterations in levels of apoptosis-associated proteins. Treatment with EA increased cell death and expression levels of caspase-8, -9, and -3. EA suppressed expression of Bcl-2, increased Bax, and reduced cleavage of Bid and the translocation of tBid to the mitochondria and the release of cytochrome c from mitochondria. EA caused a loss of mitochondrial membrane potential (ΔΨm) and an increase in cellular reactive oxygen species (ROS). EA-induced ROS formation was suppressed by cyclosporine A (an inhibitor of the ΔΨm) or allopurinol (an effective scavenger of ROS). EA also increased expression of Fas, FasL, and c-Jun N-terminal kinase (JNK), p38, and mitogen-activated protein kinase (MAPK) and decreased expression of extracellular signal-regulated kinase (ERK) 1/2-p. Co-treatment with the JNK inhibitor SP600125 inhibited EA-induced apoptosis and the activation of caspase-8, -9, and -3. Results of this study provide support for the hypothesis that EA causes cell death via apoptotic pathways in human cervical adenocarcinoma HeLa cells.     

Effects of Fraction Obtained From Korean Corni Fructus Extracts Causing Anti-Proliferation and p53-Dependent Apoptosis in A549 Lung Cancer Cells

Corni Fructus has traditionally been used as herbal medicine for the treatment of tuberculosis, asthma, hepatitis, and chronic nephritis in Korea, Japan, and China. This research was carried out to evaluate the proliferative-inhibitory effect of CF extracts against cancer cells and to identify the new pro-substance from medicinal plants. Among these herbal extracts extracted from KCF (Korean Corni Fructus), JCF (Japanese Corni Fructus) and CCF (Chinese Corni Fructus), KCF extracts strongly induced anti-proliferation of cancer cells in a dose-dependent manner compared with other extracts. Moreover, after treatment with CM/F3 (fraction 3 obtained from KCF extracts) for 24 h, A549 cells were evaluated by several indicators such as cell viability, LDH release, DNA fragmentation, nuclear condensation, and apoptotic proteins in vitro. CM/F3 showed the tumor-selective growth inhibitory activity in a dose- and time-dependent manner in A549 cells. Consistently, CM/F3 effectively induced the activation of bax, cytochrome-c, caspase-3, -8, -9, p53, and p21 causing apoptosis, and caused the suppression of Cdk2, pRb, and E2F1 related to cell arrest in A549 cells. These results demonstrate that CM/F3 caused not only anti-proliferation but also cell death involving cell arrest through interaction between apoptotic proteins and the upregulation of p53 in A549 cells.     

Induction of Apoptosis in Human Promyelocytic Leukemia HL60 Cells by an Extract From Erythrina suberosa Stem Bark

In this study, the apoptosis-inducing effect of an alcoholic extract from Erythrina suberosa stem bark (ESB) was investigated using human promyelocytic leukemia HL60 cells. Cell viability was estimated by MTT assay. We found that the ESB inhibited cell proliferation in a dose- and time-dependent manner. A series of well-documented morphological changes, such as cell shrinkage, condensation of nuclear chromatin, and nuclear fragmentation, were observed by fluorescence microscopy. The gold standard scanning electron micrographs showed apoptotic bodies and formation of blebs. Cell cycle analysis showed a significant increase in Sub G₀ population of cells above 50 μg/ml. ESB treatment resulted in a dose-dependent increase in annexin V positive cells. Increase in intracellular ROS production up to sixfold was detected in ESB-treated HL60 cells by DCFH-DA assay. Dissipation of mitochondrial membrane potential of intact cells accompanied by increase in cytosolic cytochrome c was observed, which was followed by activation of caspase-9 and -3 but not caspase-8. DNA fragmentation analysis revealed typical ladders as early as 18 h indicative of caspase-3 role in the apoptotic pathway. The overall results suggest that ESB induces mitochondria-mediated intrinsic apoptotic pathway in HL60 cells and might have therapeutic value against human leukemia.     

Sam68 is cleaved by caspases under apoptotic cell death induced by ionizing radiation

The RNA-binding protein Sam68, a mitotic substrate of tyrosine kinases, has been reported to participate in the cell cycle, apoptosis, and signaling. In particular, overexpression of Sam68 protein is known to suppress cell growth and cell cycle progression in NIH3T3 cells. Although Sam68 is involved in many cellular activities, the function of Sam68, especially in response to apoptotic stimulation, is not well understood. In this study, we found that Sam68 protein is cleaved in immune cells undergoing apoptosis induced by γ-radiation. Moreover, we found that Sam68 cleavage was induced by apoptotic stimuli containing γ-radiation in a caspase-dependent manner. In particular, we showed that activated casepase-3, 7, 8 and 9 can directly cleave Sam68 protein through in vitro protease cleavage assay. Finally, we found that the knockdown of Sam68 attenuated γ-radiation–induced cell death and growth suppression. Conclusively, the cleavage of Sam68 is a new indicator for the cell damaging effects of ionizing radiation.     

Role of wild-type p53 in apoptotic and non-apoptotic cell death induced by X-irradiation and heat treatment in p53-mutated mouse M10 cells

The sensitizing effects of wild-type p53 on X-ray-induced cell death and on heat-induced apoptosis in M10, a radiosensitive and Trp53 (mouse p53 gene)-mutated lymphoma cell line which dies through necrosis by X-irradiation, were investigated using three M10 derived transfectants with wild-type TP53 (human p53 gene). Cell death was determined by colony formation and/or dye exclusion test, and apoptosis was detected as the changes in nuclear morphology by Giemsa staining. Expression of wild-type p53 protein increased radiosensitivity of cell death as determined by both clonogenic and dye exclusion assays. This increase in radiosensitivity was attributable largely to apoptosis induction in addition to a small enhancement of necrosis. Interestingly neither pathway to cell death was accompanied by caspase-3 activation. On the other hand, heat-induced caspase-3 dependent apoptotic cell death without transfection was further increased by the transfection of wild-type p53. In conclusion, the introduction of wild-type p53 enhanced apoptotic cell death by X-rays or heat via different mechanisms that do or do not activate caspase-3, respectively. In addition, p53 also enhanced the X-ray-induced necrosis in M10 cells.     

Methanolic extract of onion (<Emphasis Type="Italic">Allium cepa</Emphasis>) attenuates ischemia/hypoxia-induced apoptosis in cardiomyocytes via antioxidant effect

Background  Although there is growing awareness of the beneficial potential of onion intake to lower the risk of cardiovascular disease, there is little information about the effect of onion on ischemic heart injury, one of the most common cardiovascular diseases. Aim of the study  This study investigates the effect of the methanol-soluble extract of onion on ischemic injury in heart-derived H9c2 cells in vitro and in rat hearts in vivo. The underlying mechanism is also investigated. Methods  To evaluate the effect of onion on ischemia-induced cell death, LDH release and TUNEL-positivity were assessed in H9c2 cells, and the infarct size was measured in a myocardial infarct model. To investigate the mechanism of the cardioprotection by onion, the reactive oxygen species (ROS) level and the mitochondrial membrane potential (ΔΨ_m) were measured using an imaging technique; the caspase-3 activity was assayed, and Western blotting was performed to examine cytochrome c release in H9c2 cells. Results  The methanolic extract of onion had a preventive effect on ischemia/hypoxia-induced apoptotic death in H9c2 cells in vitro and in rat heart in vivo. The onion extract (0.05 g/ml) inhibited the elevation of the ROS, mitochondrial membrane depolarization, cytochrome c release and caspase-3 activation during hypoxia in H9c2 cells. In the in vivo rat myocardial infarction model, onion extract (10 g/kg) significantly reduced the infarct size, the apoptotic cell death of the heart and the plasma MDA level. Conclusion  In conclusion, the results of this study suggest that the methanolic extract of onion attenuates ischemia/hypoxia-induced apoptosis in heart-derived H9c2 cells in vitro and in rat hearts in vivo, through, at least in part, an antioxidant effect. S. Park and M.-Y. Kim contributed equally to this work.     

Allomyrina dichotoma larva extract attenuates free fatty acid-induced lipotoxicity in pancreatic beta cells

BACKGROUD/OBJECTIVESAllomyrina dichotoma larva (ADL), one of the many edible insects recognized as future food resources, has a range of pharmacological activities. In a previous study, an ADL extract (ADLE) reduced the hepatic insulin resistance of high-fat diet (HFD)-induced diabetic mice. On the other hand, the associated molecular mechanisms underlying pancreatic beta-cell dysfunction remain unclear. This study examined the effects of ADLE on palmitate-induced lipotoxicity in a beta cell line of a rat origin, INS-1 cells.MATERIALS/METHODSADLE was administered to high-fat diet treated mice. The expression of apoptosis-related molecules was measured by Western blotting, and reactive oxidative stress generation and nitric oxide production were measured by DCH-DA fluorescence and a Griess assay, respectively.RESULTSThe administration of ADLE to HFD-induced diabetic mice reduced the hyperplasia, 4-hydroxynonenal levels, and the number of apoptotic cells while improving the insulin levels compared to the HFD group. Treatment of INS-1 cells with palmitate reduced insulin secretion, which was attenuated by the ADLE treatment. Furthermore, the ADLE treatment prevented palmitate-induced cell death in INS-1 cells and isolated islets by reducing the apoptotic signaling molecules, including cleaved caspase-3 and PARP, and the Bax/Bcl2 ratio. ADLE also reduced the levels of reactive oxygen species generation, lipid accumulation, and nitrite production in palmitate-treated INS-1 cells while increasing the ATP levels. This effect corresponded to the decreased expression of inducible nitric oxide synthase (iNOS) mRNA and protein.CONCLUSIONSADLE helps prevent lipotoxic beta-cell death in INS-1 cells and HFD-diabetic mice, suggesting that ADLE can be used to prevent or treat beta-cell damage in glucose intolerance during the development of diabetes.     

Radiation-induced apoptosis is independent of caspase-8 but dependent on cytochrome c and the caspase-9 cascade in human leukemia HL60 cells

We investigated the role of the caspase activation cascade in apoptosis induced by ionizing radiation or hydrogen peroxide (H(2)O(2)) in human leukemia HL60 cells. Electron paramagnetic resonance (EPR) spectra revealed that hydroxyl and hydrogen radicals were generated in the culture medium after exposure to radiation or H(2)O(2). Initial accumulation of DNA fragments at 2 h after exposure was delayed in irradiated cells compared with H(2)O(2)-treated cells, although formation of abasic sites immediately after exposure was significantly higher in irradiated cells and similar quantities of hydroxyl radicals were produced under both conditions. Activity assay of caspases revealed that caspase-3, -8 and -9 were activated 2 h after exposure to H(2)O(2), whereas in irradiated cells caspase-3 and -9 activation occurred 4 h after exposure but increased caspase-8 activation was not observed. Release of cytochrome c into cytosol was seen at 2 h after radiation and H(2)O(2) treatment. Radiation did not affect proapoptotic proteins (Bax and Bid), whereas H (2)O(2) increased accumulation of Bax in the mitochondrial membrane 2 h to 6 h after treatment, independently of the truncation of Bid by activated caspase-8. Moreover, treatment with the caspase-8 inhibitor Z-IETD-FMK increased cell survival and prevented accumulation of DNA fragments in H(2)O(2)-treated cells, but not in irradiated cells. These results suggest that, unlike the caspase cascade of H(2)O(2)-induced apoptosis, cytochrome c and caspase-9 are important for the intrinsic pathway of radiation-induced apoptosis, independent of caspase-8.     

Korean Red Ginseng Extract Inhibits IL-8 Expression via Nrf2 Activation in Helicobacter pylori-Infected Gastric Epithelial Cells

Helicobacter pylori (H. pylori) causes gastric diseases by increasing reactive oxygen species (ROS) and interleukin (IL)-8 expression in gastric epithelial cells. ROS and inflammatory responses are regulated by the activation of nuclear factor erythroid-2-related factor 2 (Nrf2) and the expression of Nrf2 target genes, superoxide dismutase (SOD) and heme oxygenase-1 (HO-1). We previously demonstrated that Korean red ginseng extract (RGE) decreases H. pylori-induced increases in ROS and monocyte chemoattractant protein 1 in gastric epithelial cells. We determined whether RGE suppresses the expression of IL-8 via Nrf2 activation and the expression of SOD and HO-1 in H. pylori-infected gastric epithelial AGS cells. H. pylori-infected cells were treated with RGE with or without ML385, an Nrf2 inhibitor, or zinc protoporphyrin (ZnPP), a HO-1 inhibitor. Levels of ROS and IL-8 expression; abundance of Keap1, HO-1, and SOD; levels of total, nuclear, and phosphorylated Nrf2; indices of mitochondrial dysfunction (reduction in mitochondrial membrane potential and ATP level); and SOD activity were determined. As a result, RGE disturbed Nrf2–Keap1 interactions and increased nuclear Nrf2 levels in uninfected cells. H. pylori infection decreased the protein levels of SOD-1 and HO-1, as well as SOD activity, which was reversed by RGE treatment. RGE reduced H. pylori-induced increases in ROS and IL-8 levels as well as mitochondrial dysfunction. ML385 or ZnPP reversed the inhibitory effect of RGE on the alterations caused by H. pylori. In conclusion, RGE suppressed IL-8 expression and mitochondrial dysfunction via Nrf2 activation, induction of SOD-1 and HO-1, and reduction of ROS in H. pylori-infected cells.