Circular RNA CDR1as Exerts Oncogenic Properties Partially through Regulating MicroRNA 641 in Cholangiocarcinoma

It has been found that the circular RNA (circRNA) CDR1as is upregulated in cholangiocarcinoma (CCA) tissues. In this study, we tried to explore the roles of CDR1as in CCA. CDR1as was overexpressed or knocked down in human CCA cells to assess the effects of CDR1as on cell behaviors and tumor xenograft growth. In vitro, the CDR1as level was significantly increased in CCA cell lines. The results showed that CDR1as promoted the cell proliferation, migration, invasion, and activation of the AKT3/mTOR pathway in CCA cells. Moreover, miR-641, a predicted target microRNA (miRNA) of CDR1as, could partially reverse the effects of CDR1as on cell behaviors in CCA cells. Furthermore, CDR1as improved tumor xenograft growth, and it could be attenuated by miR-641 in vivo Additionally, CDR1as expression was inversely correlated with miR-641 in CCA cells, and miR-641 could directly bind with CDR1as and its target genes, the AKT3 and mTOR genes. Mechanistically, CDR1as could bind with miR-641 and accelerate miR-641 degradation, which possibly leads to the upregulation of the relative mRNA levels of AKT3 and mTOR in RBE cells. In conclusion, our findings indicated that CDR1as might exert oncogenic properties, at least partially, by regulating miR-641 in CCA. CDR1as and miR-641 could be considered therapeutic targets for CCA.