Cancer-cell-intrinsic GAS2L3 promotes migration and is associated with poor prognosis in cholangiocarcinoma.

The role of growth arrest-specific 2-like 3 (GAS2L3) in cholangiocarcinoma (CCA) cells remains unclear. This study explored GAS2L3 expression, its prognostic value, and its impact on CCA cell migration. We integrated public transcriptomic data with immunohistochemistry from tumor tissues of 55 patients who underwent resection for intrahepatic CCA. Survival associations were determined using Kaplan-Meier analysis and exploratory multivariable Cox regression. To assess proliferation, actin organization, three-dimensional migration, and epithelial-mesenchymal transition (EMT) markers, we employed stable GAS2L3 knockdown in KKU-213A and KKU-055 cells. GAS2L3 transcript levels were significantly higher in tumors compared to non-tumor tissues (p < 0.01), though this transcript-level association with survival was not significant (p = 0.254). However, high GAS2L3 protein expression correlated with shorter overall survival (adjusted hazard ratio, 1.921; 95% confidence interval, 1.082-3.411; p = 0.026). GAS2L3 knockdown suppressed migration in both cell lines without significantly affecting proliferation over 72 hours. In KKU-055 cells, we observed actin redistribution and reduced cell size, while KKU-213A morphology remained largely unchanged. EMT marker responses varied by cell line: Slug and vimentin decreased in KKU-213A, whereas claudin-1 and E-cadherin increased in KKU-055. These findings suggest an intracellular role for GAS2L3 in CCA cell migration and highlight its potential as a prognostic biomarker. Further independent clinical and mechanistic validation is warranted.