MiR-193b-5p protects BRL-3A cells from acrylamide-induced cell cycle arrest by targeting FoxO3

Acrylamide (AA), an important by-product of the Maillard reaction, has been reported to be genotoxic and carcinogenic. The present study employed miRNAs to investigate the toxic mechanism of AA and their role against AA toxicity. Deep sequencing of small RNA libraries was performed and miR-193b-5p was applied for further study. AA significantly reduced the level of miR-193b-5p and its ectopic expression promoted cell cycle G1/S transition and cell proliferation by upregulating the cyclin-dependent kinase regulator Cyclin D1 and downregulating the cyclin-dependent kinase inhibitor p21, while miR-193b-5p inhibitor led to the opposite results. Dual luciferase assay demonstrated miR-193b-5p regulated the expression of FoxO3 by directly targeting the FoxO3 3'-untranslated region (3'-UTR). Knockdown of FoxO3 induced cell cycle G1/S transition and cell proliferation, which was suppressed by the inhibition of miR-193b-5p but promoted by miR-193b-5p mimics. MiR-193b-5p inhibitor strengthened the effect of FoxO3, contrary to the effect of miR-193b-5p mimics. In conclusion, miR-193b-5p acted as a regulator of cell cycle G1/S transition and cell proliferation by targeting FoxO3 to mediate the expression of p21 and Cyclin D1.