PODXL2 Promotes Cholangiocarcinoma Progression via Interactions with Ezrin and Activation of the MAPK/ERK1/2 and PI3K/AKT Signaling Pathways.

BACKGROUND

Cholangiocarcinoma (CCA), an aggressive malignancy of the biliary epithelium, is associated with poor clinical outcomes. The lack of distinct early-stage symptoms often leads to a delayed diagnosis. Therefore, the identification of reliable biomarkers and therapeutic targets is crucial for improving patient outcomes. Although podocalyxin-like protein 2 (PODXL2) is implicated in other malignancies, its role in CCA remains underexplored. We aimed to elucidate the functional role of PODXL2 in CCA and determine its prognostic significance in patient outcomes.

METHODS

PODXL2 expression was analyzed by immunohistochemistry on tissue microarrays. In vitro functional assays were performed in HuCCT1 cells with PODXL2 knockdown or overexpression. Scratch wound healing and Transwell assays evaluated cell migration and invasion. Immunofluorescence staining assessed cytoskeletal remodeling. The underlying mechanisms were explored through co-immunoprecipitation, western blot, and bioinformatic analyses.

RESULTS

Immunohistochemistry revealed markedly elevated PODXL2 expression in CCA tissues compared with that in adjacent normal tissues, and high PODXL2 levels were inversely correlated with overall survival. Functional assays demonstrated that PODXL2 overexpression promoted CCA cell migration and invasion, accompanied by cytoskeletal remodeling and altered F-actin distribution. Mechanistically, PODXL2 activated MAPK/ERK1/2 and PI3K/AKT signaling,enhancing the expression of MMP1, MMP2, and MMP9. Additionally, PODXL2-induced migration, invasion, and downstream signaling activation were attenuated following the knockdown of Ezrin.

CONCLUSIONS

PODXL2 is significantly overexpressed in CCA and associated with adverse clinical outcomes. Through interactions with Ezrin, PODXL2 promotes CCA cell migration and invasion via MAPK/ERK1/2 and PI3K/AKT pathway activation. These findings support PODXL2 as a potential diagnostic biomarker and therapeutic target in CCA.