Circ_0000591 served as endogenous RNA for miR-326 to promote progression of cholangiocarcinoma via the TLR4/MyD88/IL6 axis.

Cholangiocarcinoma (CCA) is the second most common liver malignancy with poor prognosis after hepatocellular carcinoma (HCC). Emerging evidences have proved that circular RNAs (circRNAs) are involved in the progression of multiple cancers, while their roles in tumorigenesis of CCA remains largely unclear. In the present study, we found circ_0000591 was upregulated in CCA cells and tissues. The highly expressed circ_0000591 could promote the proliferation, migration, invasion and carcinogenesis of CCA cells in vitro and in vivo. Functionally, circ_0000591 induced the proliferation, migration and invasion of CCA cells through sponging miR-326. Moreover, silencing of circ_0000591 attenuated LPS-induced anti-apoptosis of CCA cells through the TLR4/MyD88/IL6 pathway. In conclusion, this study revealed a novel regulatory mechanism that circ_0000591 contributed to the progression of CCA via miR-326/TLR4/MyD88/IL6 axis. These findings enhanced our knowledge of potential molecular mechanism involved in the malignant progression of CCA.