ABSTRACT: Background: circRNAs, a recently identified new member of non-coding RNAs, have been proved to play an essential role in the development and progression of various cancers. However, the functions and mechanisms of circRNAs in colorectal liver metastasis have not been fully elucidated. Methods: We performed circRNA microarray to screen differentially expressed novel circRNAs in the pathology of colorectal liver metastasis. Quantitative real-time PCR was used to detect the circ102049 expression in colorectal cancer (CRC) samples. Then CRC cells were transfected with a circ102049 over-expression vector or siRNAs, and the effects of circ102049 on biological functions in CRC cells were accessed in vitro. Mechanistically, the bioinformatics analysis, fluorescence in situ hybridization, RIP assay, RNA pull down assay and luciferase reporter assay were conducted to confirm the relationships among circ102049, miR-761, miR-192-3p and FRAS1. Moreover, the mechanism of circ102049 how to recruit and distribute DGCR8 protein in cytoplasm was elucidated. Results: The results showed that circ102049 was highly expressed in primary CRC tumors with liver metastasis and closely correlated with the CRC patients' prognosis. Circ102049 might act as a novel metastasis-related non-coding RNA, and significantly promote the adhesion, migration and invasion abilities of CRC cells. Mechanistically, we verified that circ102049 promoted the CRC development and progression via a miR-761/miR-192-3p-FRAS1-dependent mechanism. Notably, due to the distribution of DGCR8 protein, circ102049 might also reduce the mature products of miR-761 and miR-192-3p in cytoplasm indirectly. In addition, the role of circ102049 in promoting colorectal liver metastasis was also confirmed in vivo. Conclusions: Our findings provided new clues that circ102049 might be a potential prognostic factor in CRC, and the circ102049-miR-761/miR-192-3p-FRAS1 axis could be further explored as a therapeutic target for anti-metastatic therapy in CRC patients with liver metastases. Keywords: Hsa_circ_102049, miR-761, miR-192-3p, FRAS1, Colorectal liver metastasis
