FBXW2 inhibits the progression of gastric cancer via promoting β-catenin ubiquitylation

Background: F-box and WD-repeat-containing protein 2 (FBXW2), an E3 ubiquitin ligase, may play a crucial role in tumorigenesis. However, its function in gastric cancer remains unknown. Methods: The expression levels of FBXW2 and β-catenin in gastric cancer samples were analyzed using RT-PCR and immunohistochemistry, with Pearson correlation analysis to assess their relationship. AGS and HGC-27 gastric cancer cells were transfected with sh-FBXW2, and their viability was evaluated using the CCK8 assay, while invasion ability was assessed via the transwell assay. Western blotting was performed to measure the expression levels of FBXW2, β-catenin, GSK3β, and Axin2 in AGS cells. Additionally, a ubiquitination assay was conducted to examine the effect of sh-FBXW2 on β-catenin ubiquitination. Immunoprecipitation was used to determine the potential interaction between FBXW2 and β-catenin. Results: FBXW2 expression was downregulated, whereas β-catenin expression was upregulated in gastric cancer tissues compared to adjacent normal tissues, showing a significant negative correlation (r = -0.52, P < 0.001). Knockdown of FBXW2 (sh-FBXW2) promoted gastric cancer cell viability and invasion while increasing β-catenin expression and reducing GSK3β and Axin2 levels. Furthermore, FBXW2 was found to bind β-catenin and facilitate its ubiquitination, leading to enhanced nuclear translocation of β-catenin. Conclusions: FBXW2 suppresses gastric cancer progression by promoting β-catenin ubiquitination, highlighting its potential as a therapeutic target.