Survivin is a direct target of miR-330-5p. (A) Schematic of the survivin 3′-UTR containing the miR-330-5p binding site. (B) Survivin expression was measured by reverse transcription-quantitative polymerase chain reaction in OS tissues (n=63) and osteochondroma tissues (n=20). (C) Survivin expression was negatively associated with miR-330-5p expression in OS tissues (r=−0.8696, P<0.01). (D) 293T cells were co-transfected with 80 ng survivin-3′-UTR wt or mut reporter plasmids, and with 50 nM miR-330-5p mimics, mimics NC, miR-330-5p inhibitor or inhibitor NC for 48 h, and relative luciferase activity was measured. (E) U2OS and (F) MG63 cells were transfected with the 50 nM miR-330-5p mimics, mimics-NC, miR-330-5p inhibitor or inhibitor NC for 48 h, and then survivin protein expression was determined by western blot analysis. Data represent the mean ± standard deviation of three independent experiments. **P<0.01. miR, microRNA; OS, osteosarcoma; NC, negative control; 3′-UTR, 3′-untranslated region; wt, wild-type; mut, mutant.