WWOX Suppresses Gastric Cancer Cell Proliferation, Migration, and EMT by Negatively Regulating the Wnt/β-Catenin Signaling Pathway.

OBJECTIVE: This study aims to unveil whether WWOX modulates epithelial-mesenchymal transition (EMT), proliferation, and invasive capacity of gastric cancer (GC) cells via regulating the Wnt/β-catenin signaling pathway. METHODS: WWOX expression in GC cell lines was assessed by Western blotting (WB) and immunofluorescence. Gain- and loss-of-function approaches were employed by establishing stable WWOX-overexpressing (oe WWOX) MKN28 and HGC27 cell lines and performing siRNA-mediated WWOX (si WWOX) knockdown in the same cell lines. Cell proliferation and invasion were evaluated using CCK-8 and Transwell assays, and EMT-related protein expression was examined by WB. To determine whether WWOX functions through the Wnt/β-catenin pathway, oe WWOX cells were treated with the pathway agonist SKL2001, and WWOX-silenced cells were treated with the β-catenin inhibitor XAV939; β-catenin levels in whole-cell lysates, as well as nuclear and cytoplasmic fractions, were analyzed by WB. The in vivo effects of WWOX overexpression and knockdown were assessed using subcutaneous xenograft models in nude mice. RESULTS: WWOX expression was markedly reduced in GC cells. WWOX overexpression significantly suppressed proliferation, invasion, and EMT, accompanied by decreased β-catenin levels in total cell lysates as well as in nuclear and cytoplasmic fractions. Conversely, WWOX knockdown promoted malignant phenotypes and increased β-catenin expression in both fractions. SKL2001 treatment effectively counteracted the tumor-suppressive effects of WWOX overexpression, whereas XAV939 treatment reversed the tumor-promoting effects induced by WWOX knockdown. In vivo, WWOX overexpression suppressed tumor growth and reversed EMT, while WWOX knockdown promoted tumor growth and EMT progression; these changes were associated with reciprocal alterations in WWOX and β-catenin expression in tumor tissues. CONCLUSION: WWOX suppresses GC cell proliferation, invasion, and EMT both in vitro and in vivo by negatively regulating the Wnt/β-catenin signaling pathway. These findings provide a mechanistic basis for targeting the WWOX/Wnt/β-catenin axis as a potential therapeutic strategy for GC.