Niclosamide inhibits the proliferation of human osteosarcoma cell lines by inducing apoptosis and cell cycle arrest

Niclosamide, used as an antihelminthic, has demonstrated some properties of anticancer effects. However, its role in osteosarcoma remains to be determined. The aim of this study was to determine the effect of niclosamide on human osteosarcoma cell lines. The human MG-63 and U2OS osteosarcoma cell lines were treated with different concentrations of niclosamide. The cell inhibitory rate was calculated by CCK-8 assay. Cell cycle was detected by flow cytometry. Cell apoptosis was determined by Hoechst 33324 staining, flow cytometry and fluorescence microscope, respectively. The expression of bcl-2, bax and pro-caspase-3 were measured by western blotting. Niclosamide exerted an inhibitory effect on the two cell lines in a time- and dose-dependent manner. Niclosamide was found to induce the arrest of S and G2/M phase in U2OS cells and G2/M in MG-63 cells. Moreover, niclosamide induced apoptosis in MG-63 and U2OS cells. The bax/bcl-2 ratio increased while the expression of pro‑caspase-3 decreased significantly in the two cell lines. The results indicated that niclosamide inhibits proliferation, and induces apoptosis and cell cycle arrest in human osteosarcoma cell lines.