Artesunate inhibits growth and induces apoptosis in human osteosarcoma HOS cell line in vitro and in vivo

This paper aims to investigate the effects of artesunate （ART） on growth and apoptosis in human osteosarcoma HOS cell line in vitro and in vivo and to explore the possible underlying mechanisms. Cell viability was measured by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay. The induction of apoptosis was detected by light and transmission electron microscopy and flow cytometry. Western blot analysis was used to investigate the related mechanisms. Nude mice were further employed to investigate the antitumour activity of ART in vivo. MTT assay results demonstrated that ART selectively inhibits the growth of HOS cells in a dose- and time-dependent manner. Based on the findings of light and transmission electron microscopy, Hoechst 33258 staining, and fluoreseein isothiocyanate （FITC）-annexin V staining, the cytotoxicity of ART in HOS cells occurs through apoptosis. With ART treatment, cytosolic cy- tochrome c was increased, Bax expression was gradually and caspase-9 and caspase-3 were activated. Thus, the upregulated, Bcl-2 expression was downregulated, intrinsic apoptotic pathway may be involved in ART-induced apoptosis. Cell cycle analysis by flow cytometry indicated that ART may induce cell cycle arrest at Gz/M phase. In nude mice bearing HOS xenograft tumours, ART inhibited tumour growth and regulated the expressions of cleaved caspase-3 and survivin, in agreement with in vitro observations. ART has a selective antitumour activity against human osteosarcoma HOS cells, which may be related to its effects on induction of apoptosis via the intrinsic pathway. The results suggest that ART is a promising candidate for the treatment of osteosarcoma.