miR-185 influences Cdc42-N-WASP signaling pathway in gastric cancer by targeting CTTN

Background: miR-185 expression is dysregulated in various tumors, but its role in gastric cancer remains unclear. Objectives: To investigate miR-185 expression and clinical significance in gastric cancer, explore its effects on malignant phenotypes and preliminarily elucidate the underlying mechanism. Methods: Real-time polymerase chain reaction (PCR) was used to detect miR-185 expression in 58 archived gastric cancer tissue samples and paired adjacent normal tissues obtained from a hospital biospecimen repository. In SGC-7901 and AGS cells, the effects of miR-185 modulation on proliferation, apoptosis, epithelial-mesenchymal transition (EMT) and the cell division cycle protein 42 (Cdc42)-neural Wiskott-Aldrich syndrome protein (N-WASP) pathway were assessed using 5-ethynyl-2?-deoxyuridine (EdU) assay, flow cytometry, Western blot and dual-luciferase reporter assay. Results: miR-185 expression was significantly downregulated in gastric cancer tissues and correlated with lymph node metastasis and advanced stage. In vitro, miR-185 overexpression inhibited proliferation, induced apoptosis, increased E-cadherin expression and decreased Vimentin, N-cadherin, Snail, Cdc42 and neural WASP expression. A dual-luciferase reporter assay confirmed that cortactin (CTTN) is a direct target of miR-185. These findings were consistent in both cell lines. Conclusion: miR-185 is downregulated in gastric cancer and its low expression correlates with lymph node metastasis and advanced TNM stage. In vitro experiments indicate that upregulation of miR-185 suppresses gastric cancer cell proliferation, induces apoptosis and reverses epithelial-mesenchymal transition, possibly by targeting CTTN and thereby affecting Cdc42 and N-WASP expression. This single-center, small-sample (n=58) in vitro study lacks in vivo validation; the findings require confirmation in larger, multicenter cohorts. Nevertheless, this study provides the first experimental evidence for the miR-185/CTTN/Cdc42-N-WASP axis in gastric cancer.