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?-Lipoic acid inhibits Helicobacter pylori-induced oncogene expression and hyperproliferation by suppressing the activation of NADPH oxidase in gastric epithelial cells.

ABSTRACT: Hyperproliferation and oncogene expression are observed in the mucosa of Helicobacter pylori- (H. pylori-) infected patients with gastritis or adenocarcinoma. Expression of oncogenes such as ?-catenin and c-myc is related to oxidative stress. ?-Lipoic acid (?-LA), a naturally occurring thiol compound, acts as an antioxidant and has an anticancer effect. The aim of this study is to investigate the effect of ?-LA on H. pylori-induced hyperproliferation and oncogene expression in gastric epithelial AGS cells by determining cell proliferation (viable cell numbers, thymidine incorporation), levels of reactive oxygen species (ROS), NADPH oxidase activation (enzyme activity, subcellular levels of NADPH oxidase subunits), activation of redox-sensitive transcription factors (NF-?B, AP-1), expression of oncogenes (?-catenin, c-myc), and nuclear localization of ?-catenin. Furthermore, we examined whether NADPH oxidase mediates oncogene expression and hyperproliferation in H. pylori-infected AGS cells using treatment of diphenyleneiodonium (DPI), an inhibitor of NADPH oxidase. As a result, ?-LA inhibited the activation of NADPH oxidase and, thus, reduced ROS production, resulting in inhibition on activation of NF-?B and AP-1, induction of oncogenes, nuclear translocation of ?-catenin, and hyperproliferation in H. pylori-infected AGS cells. DPI inhibited H. pylori-induced activation of NF-?B and AP-1, oncogene expression and hyperproliferation by reducing ROS levels in AGS cells. In conclusion, we propose that inhibiting NADPH oxidase by ?-LA could prevent oncogene expression and hyperproliferation occurring in H. pylori-infected gastric epithelial cells.

SUBMITTER: Byun E

PROVIDER: S-EPMC4152957 | biostudies-other | 2014

REPOSITORIES: biostudies-other

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α-Lipoic acid inhibits Helicobacter pylori-induced oncogene expression and hyperproliferation by suppressing the activation of NADPH oxidase in gastric epithelial cells.

Byun Eunyoung E Lim Joo Weon JW Kim Jung Mogg JM Kim Hyeyoung H

Mediators of inflammation 20140819

Hyperproliferation and oncogene expression are observed in the mucosa of Helicobacter pylori- (H. pylori-) infected patients with gastritis or adenocarcinoma. Expression of oncogenes such as β-catenin and c-myc is related to oxidative stress. α-Lipoic acid (α-LA), a naturally occurring thiol compound, acts as an antioxidant and has an anticancer effect. The aim of this study is to investigate the effect of α-LA on H. pylori-induced hyperproliferation and oncogene expression in gastric epithelial ...[more]

PMID: 25210229

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Project description:Helicobacter pylori (H. pylori) classified as a class I carcinogen by the World Health Organization (WHO) plays an important role in the progression of chronic gastritis and the development of gastric cancer. A major bioactive component of Evodia rutaecarpa, evodiamine, has been known for its anti-bacterial effect and anti-cancer effects. However, the inhibitory effect of evodiamine against H. pylori is not yet known and the inhibitory mechanisms of evodiamine against gastric cancer cells are yet to be elucidated concretely. In this study, therefore, anti-bacterial effect of evodiamine on H. pylori growth and its inhibitory mechanisms as well as anti-inflammatory effects and its mechanisms of evodiamine on H. pylori-induced inflammation were investigated in vitr. Results of this study showed the growth of the H. pylori reference strains and clinical isolates were inhibited by evodiamine. It was considered one of the inhibitory mechanisms that evodiamine downregulated both gene expressions of replication and transcription machineries of H. pylori. Treatment of evodiamine also induced downregulation of urease and diminished translocation of cytotoxin-associated antigen A (CagA) and vacuolating cytotoxin A (VacA) proteins into gastric adenocarcinoma (AGS) cells. This may be resulted from the reduction of CagA and VacA expressions as well as the type IV secretion system (T4SS) components and secretion system subunit protein A (SecA) protein which are involved in translocation of CagA and VacA into host cells, respectively. In particular, evodiamine inhibited the activation of signaling proteins such as the nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and the mitogen-activated protein kinase (MAPK) pathway induced by H. pylori infection. It consequently might contribute to reduction of interleukin (IL)-8 production in AGS cells. Collectively, these results suggest anti-bacterial and anti-inflammatory effects of evodiamine against H. pylori.

Dataset Information

?-Lipoic acid inhibits Helicobacter pylori-induced oncogene expression and hyperproliferation by suppressing the activation of NADPH oxidase in gastric epithelial cells.

Publications

α-Lipoic acid inhibits Helicobacter pylori-induced oncogene expression and hyperproliferation by suppressing the activation of NADPH oxidase in gastric epithelial cells.

Similar Datasets

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