Association of aberrant expression of CD39 with the outcome of patients with cholangiocarcinoma.

93 Background: Cholangiocarcinoma is defined as a kind of malignant tumor originating from bile ducts. Due to the lack of effective diagnostic and treatment methods, the prognosis of cholangiocarcinoma is dismal. Accumulating evidence indicates that CD39 could promote the progression of several types of cancer. However, the biological function and the underlying mechanism of CD39 in cholangiocarcinoma have not been well investigated. Methods: Quantitative reverse transcription PCR (RT-qPCR), western blot (WB), and immunohistochemistry staining was used to evaluate the expression level of CD39 in cholangiocarcinoma. Kaplan-Meier and Cox hazard ratio regression analyses were implicated to evaluate the prognostic significance of CD39. Cell counting kit-8 (CCK-8) was carried out to evaluate the proliferative capacity, while transwell assay was used to detect the migration and invasion ability. In addition, B-NDG mice were used for the in vivo assay. The potential protein binding with the CD39 was identified through co-immunoprecipitation. Results: We observed that CD39 was aberrantly expressed in the tumor tissue and cholangiocarcinoma cell lines. Our analysis indicated that the high expression level of CD39 correlated with aggressive clinicopathological characteristics, and CD39 was identified as an independent poor prognostic factor in cholangiocarcinoma. In addition, our in vitro and in vivo data indicated that the knockdown of CD39 could suppress the proliferation, migration, invasion ability, and the epithelial-mesenchymal transition (EMT) process of cholangiocarcinoma. Opposite results were observed when CD39 was overexpressed. Mechanistically, CD39 could bind with Annexin A2 (ANXA2), which influences the phosphorylation level of ANXA2 at the Tyr24 site, thereby promoting the activation of PI3K/AKT signaling, which resulted in the biological change in cholangiocarcinoma. Conclusions: Our data indicated that CD39 was overexpressed in the tumor tissue. Meanwhile, CD39 was identified as an independent prognostic factor of poor overall survival for patients withcholangiocarcinoma. In terms of the biological role of CD39, our data indicated that CD39 promoted the progression and metastasis of cholangiocarcinoma through binding with ANXA2, and through activating the PI3K/AKT signaling. In brief, CD39 is a potential prognostic factor and therapeutical target for cholangiocarcinoma.