Simple SummaryColorectal cancer (CRC) is the third leading cause of cancer deaths worldwide, and no cure exists for most patients at advanced stages with distant metastasis.CircUHRF2has been aberrantly expressed in CRC, but its role in CRC growth and metastasis remains largely unclear. This study demonstrated thatcircUHRF2was upregulated in CRC and correlated with poor prognostic outcomes in CRC patients. Methyltransferase-like 3 (METTL3) facilitatedcircUHRF2expression through N6-methyladenine modification (m6A) modification.circUHRF2or METTL3 silencing suppressed in vitro cell stemness, migration, and invasion; and in vivo tumor growth and liver metastasis. Furthermore,circUHRF2is bound with insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) and increases the stability and expression of DEAD-box helicase 27 (DDX27) mRNA. Anti-cancer effect ofcircUHRF2silencing was counteracted by DDX27 overexpression. Our identification of the oncogenic roles ofcircUHRF2and METTL3 in CRC progression as well as their regulatory function through the IGF2BP1-DDX27 axis, has broadened our current knowledge about CRC and may help the future development of more efficient treatments.AbstractIncreasing evidence has implicated that circular RNAs (circRNAs) exert important roles in colorectal cancer (CRC) occurrence and progression. However, the role of a novel circRNA,circUHRF2, remains unknown in CRC. Our work aimed at identifying the functional roles ofcircUHRF2in CRC and illustrating the potential mechanisms. As assessed by quantitative real-time PCR (qRT-PCR),circUHRF2and methyltransferase-like 3 (METTL3) were highly expressed in CRC specimens and cells. Sanger sequencing and RNase R assays were performed to verify the ring structure ofcircUHRF2. Notably, aberrantly increased expression ofcircUHRF2was positively correlated with poor prognosis of CRC patients. Functional experiments indicated that CRC stemness, migration, and epithelial-mesenchymal transition (EMT) were suppressed by the knockdown ofcircUHRF2or METTL3. Mechanistically, METTL3 enhancedcircUHRF2expression through N6-methyladenine (m6A) modification. Rescue experiments showed that overexpression ofcircUHRF2reversed the repressive effect of METTL3 silencing on CRC progression. Moreover,circUHRF2inhibited the loss of DEAD-box helicase 27 (DDX27) protein via promoting the interaction between insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) andDDX27mRNA. DDX27 knockdown repressed CRC malignant properties, which was counteracted bycircUHRF2overexpression. The in vivo assays in nude mice demonstrated thatcircUHRF2or METTL3 silencing exerted a suppressive effect on CRC growth and liver metastasis via repressing DDX27 protein expression. Taken together, METTL3-mediated m6A modification upregulatedcircUHRF2and subsequently inhibited loss of DDX27 protein via recruitment of IGF2BP1, which conferred CRC stemness and metastasis. These findings shed light on CRC pathogenesis and suggestcircUHRF2as a novel target for CRC treatment.