circNSUN2 promotes the malignant biological behavior of colorectal cancer cells via the miR‑181a‑5p/ROCK2 axis.

Aberrant expression of circular RNAs (circRNAs) has been demonstrated to be related to the development of colorectal cancer (CRC), the third most common cancer worldwide. However, the mechanism of the effect of circRNA NOP2/Sun domain family, member 2 (circNSUN2) on the malignant biological behavior of CRC remains unclear. In the present study, the expression of circNSUN2 and microRNA (miR)‑181a‑5p was detected by RT‑qPCR. The expression of Rho‑associated coiled‑coil‑containing protein kinase 2 (ROCK2) was measured by western blotting. Cell proliferation was detected by CCK‑8 assay. The cell apoptosis rate was measured by flow cytometry. Cell migration ability was evaluated by Transwell assay. The interactions between circNSUN2, miR‑181a‑5p and ROCK2 were verified by dual‑luciferase reporter assay. The results revealed that circNSUN2 was highly expressed in CRC tissues and cell lines. Knockdown of circNSUN2 inhibited the malignant biological behavior of CRC in vivo and in vitro. Moreover, miR‑181a‑5p was revealed to be a target gene of circNSUN2, and the expression of ROCK2 was negatively regulated by miR‑181a‑5p. Knockdown of circNSUN2 inhibited proliferation and migration, and induced apoptosis of CRC cells and suppressed tumor growth by targeting miR‑181a‑5p to decrease ROCK2 expression. In conclusion, circNSUN2 promoted the progression of CRC by sponging miR‑181a‑5p to increase the expression of ROCK2.