Knockdown of circNRIP1 sensitizes colorectal cancer to 5­FU via sponging miR­532­3p.

The present study aimed to investigate the influence of circular RNA nuclear receptor­interacting protein 1 (circNRIP1) on the chemotherapeutic effect of 5­fluorouracil (5­FU) in colorectal cancer (CRC) and reveal its potential molecular mechanisms. The effects of circNRIP1 on cell proliferation, migration and invasion, and apoptosis were evaluated using Cell Counting Kit­8, Transwell and flow cytometric assays, respectively. A dual­luciferase reporter assay was performed to verify the potential interaction between circNRIP1 and microRNA (miR)­532­3p. The results of the present study indicated that circNRIP1 was upregulated in CRC and its increased expression was associated with CRC progression. Furthermore, overexpression of circNRIP1 promoted CRC cell proliferation, invasion and migration, while it inhibited apoptosis. Knockdown of circNRIP1 significantly enhanced the 5­FU­induced inhibition of the viability of HCT116 and SW480 cells. Bioinformatics analysis predicted that miR­532­3p was a direct target of circNRIP1, which was further confirmed by a dual­luciferase reporter assay. miR­532­3p silencing reversed the effects of circNRIP1 knockdown on the sensitivity of 5­FU in the chemotherapy of CRC. The results suggested that circNRIP1 and miR­532­3p may be utilized to improve the diagnosis of CRC and serve as diagnostic markers. In conclusion, overexpression of circNRIP1 promoted the progression of CRC, while circNRIP1 silencing sensitized CRC cells to 5­FU via sponging miR­532­3p.