Transcriptome Analysis of the Inhibitory Effect of Astaxanthin onHelicobacter pylori-Induced Gastric Carcinoma Cell Motility

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 inH. 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 ofH. pyloriinfection and ASTX administration. The results were used to identify genes that are differently expressed in response toH. pyloriand 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, PLC gamma 1, 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 ofH. pylori-infection. We propose thatH. 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 counteractH. pylori-induced activation of PI3K and PLC gamma. In conclusion, ASTX can suppressH. pylori-induced gastric cancer progression by inhibiting cytoskeleton reorganization and reducing cell motility through downregulation of c-MET, EGFR, PI3KC2, PLC gamma 1, Cdc42, and ROCK1.