Helicobacter pylori (H. pylori)
infection promotes the
metastasis of gastric
carcinoma cells by modulating signal transduction pathways that regulate cell proliferation, motility, and invasion.
Astaxanthin (ASTX), a xanthophyll
carotenoid, is known to inhibit
cancer cell migration and invasion, however the mechanism of action of ASTX in H. pylori-infected gastric epithelial cells is not well understood. To gain insight into this process, we carried out a comparative
RNA sequencing (
RNA-Seq) analysis of human
gastric cancer AGS (
adenocarcinoma gastric) cells as a function of H. pylori
infection and ASTX administration. The results were used to identify genes that are differently expressed in response to H. pylori and ASTX. Gene ontology (GO) analysis identified differentially expressed genes (DEGs) to be associated with cell cytoskeleton remodeling, motility, and/or migration. Among the 20 genes identified, those encoding c-MET, PI3KC2, PLCγ1, Cdc42, and ROCK1 were selected for verification by real-time PCR analysis. The verified genes were mapped, using signaling networks contained in the KEGG database, to create a signaling pathway through which ASTX might mitigate the effects of H. pylori-
infection. We propose that H. pylori-induced upregulation of the upstream regulator c-MET, and hence, its downstream targets Cdc42 and ROCK1, is suppressed by ASTX. ASTX is also suggested to counteract H. pylori-induced activation of PI3K and PLCγ. In conclusion, ASTX can suppress H. pylori-induced
gastric cancer progression by inhibiting cytoskeleton reorganization and reducing cell motility through downregulation of c-MET, EGFR, PI3KC2, PLCγ1, Cdc42, and ROCK1.