Aim: To explore the function of circular RNA CUL2 (circCUL2) in colorectal cancer progression.

Method: RT-PCR was carried out to detect the expression of circCUL2 in colorectal cancer tissues and cell lines. Western blot and immunofluorescence were used to determine the level of autophagy. CCK-8, clone formation assay, and EdU staining were used to assess the proliferation ability. Luciferase assay verified the relationship between miR-208a-3p and circCUL2 /PPP6C. The xenograft mouse model was used to confirm the function of circCUL2 in vivo.

Results: The expression level of circCUL2 was down-regulated in colorectal cancer tissues and cell lines. Forcing expression of circCUL2 inhibited proliferation ability, induced apoptosis, and autophagy in colorectal cancer cells. Luciferase assay verified that miR-208a-3p could bind with circCUL2/PPP6C. Overexpression of circCUL2 could inhibit cancer progression via targeting the miR-208a-3p/PPP6C signal pathway.

Conclusion: CircCUL2 participates in progression via the miR-208a-3p/PPP6C axis in colorectal cancer. CircCUL2 would be an underlying target for the diagnosis and therapy of colorectal cancer.