Long non-coding RNA EPIC1 promotes cholangiocarcinoma cell growth

Cholangiocarcinoma (CCA) is the as the most frequently observed biliary tract malignancy, which has low survival rate in addition to constrained treatment options. However, the fundamental molecular mechanism underlying malignant progression of CCA is quite ambiguous. Recent studies reported that long non-coding RNA (lncRNA) might play critical roles in regulating chemo-resistant of multiple types of cancer. In this study, our results indicate that the LncRNA-EPIC1 expression were significantly increased in cholangiocarcinoma tissues, compared to adjacent normal tissues. And also, its expression also increased in several CCA cancer cell lines than that in human normal immortalized cholangiocyte cell. Loss-and-gain of Lnc-EPIC1 contributes to the CCA cell growth, colony formation, cell apoptosis and also cell cycle. Myc has been reported to directly interact with Lnc-EPIC1 in several cancer cells. Myc targets, including Cyclin A/D and CDK9 were downregulated by Lnc-EPIC1 siRNA. Myc knockout also suppresses the CCA cell growth, colony formation and cell apoptosis. However, Lnc-EPIC1 knockdown failed to enhance the Myc-KO-induced suppression of CCA tumor progression. RNA immunoprecipitation (RIP) results showed the direct interaction between Lnc-EPIC1 and Myc. Taken together, our results show that Lnc-EPIC1 promotes CCA cancer progression by targeting Myc.