CDKN1A is a target gene of miR-106b-5p. (A) Binding sites between WT and MUT CDKN1A 3'-UTR and miR-106b-5p. (B) Luciferase reporter assays were performed on 293T cells transfected with WT or MUT CDKN1A 3'-UTR vectors and miR-106b-5p inhibitor or miR-NC. (C) RT-qPCR analysis of CDKN1A mRNA levels in Saos-2 and U2OS cells transfected with the miR-106b-5p inhibitor or miR-NC. (D) Western blot analysis of p21 protein level in Saos-2 and (E) U2OS cells transfected with miR-106b-5p inhibitor or miR-NC. (F) mRNA expression of CDKN1A relative to GAPDH in human OS tissues and adjacent tissues, as detected via RT-qPCR. ***P<0.001 as indicated. (G) A Negative correlation between miR-106b-5p and CDKN1A expression was identified in OS tissues. Data are presented as the mean ± standard deviation. **P<0.01 and ***P<0.001 vs. NC group. CDKN1A, cyclin-dependent kinase inhibitor 1A; miR, microRNA; WT, wild-type; MUT, mutant; UTR, untranslated region; NC, negative control; RT-qPCR, reverse transcription-quantitative; OS, osteosarcoma.