Inhibitory Effects of Menadione on Growth and -Induced Inflammation via NF-κB Inhibition.

is classified as a group I carcinogen by WHO because of its involvement in gastric cancer development. Several reports have suggested anti-bacterial effects of menadione, although the effect of menadione on major virulence factors of and -induced inflammation is yet to be elucidated. In this study, therefore, we demonstrated that menadione has anti- and anti-inflammatory effects. Menadione inhibited growth of reference strains and clinical isolates. Menadione reduced expression of A in , and translocation of VacA protein into AGS (gastric adenocarcinoma cell) was also decreased by menadione treatment. This result was concordant with decreased apoptosis in AGS cells infected with . Moreover, cytotoxin-associated protein A (CagA) translocation into -infected AGS cells was also decreased by menadione. Menadione inhibited expression of several type IV secretion system (T4SS) components, including B2, B7, B8, and B10, that are responsible for translocation of CagA into host cells. In particular, menadione inhibited nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) activation and thereby reduced expression of the proinflammatory cytokines such as IL-1β, IL-6, IL-8, and TNF-α in AGS as well as in THP-1 (monocytic leukemia cell) cell lines. Collectively, these results suggest the anti-bacterial and anti-inflammatory effects of menadione against .