Objective To detect the expression of miRNA-130b in osteosarcoma tissues and investigate the effect of miRNA-130b on the proliferation, cell cycle and apoptosis of human osteosarcoma cell line U2.

Methods Real-time PCR was used to detect the expression level of miRNA-130b in osteosarcoma tissues and corresponding paratumorous tissues collected from 48 patients.The expression level of miRNA-130b in osteosarcoma cell line U2 was measured by qRT-PCR after transfected with miRNA-130b inhibitor. The cell proliferation was determined by CCK8 assay.Flow cytometry was used to monitor cell cycle and apoptosis. Luciferase gene reporter assay was used to detect the regulation mechanism of miRNA-130b and RUNX3. The change of RUNX3 and miRNA-130b of U2 cells after transfection was detected.

Results miRNA-130b was highly expressed in osteosarcoma tissues, compared with the adjacent normal tissues. The miRNA-130b expression of U2 cells after transfection was significantly down-regulated. The proliferation activity of U2 cells was inhibited, the cell cycle was arrested in G₀/G₁ phase, and the cell apoptosis was increased after transfected with miRNA-130b inhibitor. We found that miRNA-130b reduced wide-type RUNX3 3′-UTR luciferase expression intensity. The relative expression of RUNX3 in miRNA-130b inhibitor transfection group was significantly higher than those in negative control group. The relative expression of miRNA-130b in RUNX3 siRNA transfection group had no significant difference with those in negative control group.

Conclusion miRNA-130b is highly expressed in human osteosarcoma tissue. miRNA-130b may inhibit the proliferation and induce the apoptosis of osteosarcoma cell line U2 via inhibiting the RUNX3 expression in vitro.