Study on the Probiotics Regulating miRNA in H. Pylori-induced Wnt/β-catenin Gastric Carcinogenesis.

Background. H. pylori has recognized as a type 1 carcinogen for gastric adenocarcinoma. Although H. pylori eradication promises to reduce the risk of gastric cancer, the regression rate of intestinal metaplasia (IM) after eradication is unsatisfactory. Therefore, to find the mechanism of IM persistent and a new strategy to improve IM regression are critical for reducing gastric cancer development. The canonical Wnt/beta-catenin signaling pathway upregulating cyclooxygenase-2 (COX-2) transcriptional activity involves gastric carcinogenesis after H. pylori infection. Investigators have established an in vitro model that H. pylori induces a cagA-dependent nuclear COX-2 expression in both GES-1 and AGS cells. MicroRNAs (miRNAs) are a class of widespread non-coding RNAs and have been shown to involve in the gastric carcinogenesis. Among these gastric cancer-related miRNA candidates, some were reported to interact with Wnt/β-catenin pathway. Clinically, H. pylori eradication plus celecoxib therapy results in about one-third cases being IM regression, which correlated to the nuclear β-catenin and COX-2 expression before treatment. Based on the probiotics ingestion can ameliorate H. pylori-induced inflammatory pathways, investigators hypothesis that H. pylori eradication with probiotics supplement may promote IM regression through regulating certain miRNAs and Wnt/β-catenin signaling. The aims of this 3-year grant will 1. to establish the H. pylori induces the Wnt/beta-catenin and COX-2 signaling pathway in vitro. 2. to investigate the effects and mechanisms of L. acidophilus and B. latis on H. pylori-induced Wnt/beta-catenin oncogenesis pathway. 3. to study whether probiotics ingestion promote IM regression or ameliorate IM progression in H. pylori-infected patients after successful eradication therapy. Materials and Methods. A H. pylori (HP238) isolate strain, GES-1, and AGS cells will be used for in vitro study. The protein levels of cell tests will measured by western