Carbonic anhydrase 2 is a promising predictive factor in cholangiocarcinoma and potential mediator in Metformin treatment
Abstract Background Cholangiocarcinoma (CCA) is a rare tumor with an aggressive behavior, early diagnosis is impossible as symptoms emerge only in advanced stages. The discovery of a promising biomarker is urgently needed. Carbonic anhydrase 2 (CA2) was found to be dysregulated in diverse cancers, however limited knowledge of CA2 in CCA development was known. Materials and methods CA2 expression was detected both in human and rat thioacetamide (TAA)-induced CCA model by RT-PCR and IHC staining. The relationship of CA2 expression with clinical outcomes was evaluated by univariate and multivariate analyses. CA2 expression changes were also detected both in vivo and in vitro by a potential CA2 inhibitor, Metformin (Met), which was used to inhibit CCA development. Results The level of CA2 expression was increased in biliary lesions with continuous administration of TAA. CA2 was overexpressed in CCA compared with normal tissue samples in rat model and human samples, and correlated significantly with disease progression. Patients with high CA2 expression had a poorer outcome than those without CA2 expression. Met alleviated TAA-induced CCA lesions, and significantly decreased CA2 expression. Colony formation assay showed Met inhibition in CCA cell abilities to form colonies and CA2 expression. CA2 expression was downregulated by Met in a dose- and time-dependent manner in vitro. Conclusions These findings indicate that CA2 is a promising predictive and prognostic factor, and might serve as a potentially novel therapeutic target for human CCA.