Antineoplastic effect of calycosin on osteosarcoma through inducing apoptosis showing in vitro and in vivo investigations.

Recently, increasing studies have documented that tumorigenesis closely relates to apoptotic processes. Thus, inducing apoptosis is an anti-cancer strategy against osteosarcoma. Here we investigated the anti-proliferative effect of calycosin on human osteosarcoma cell (143B) in vitro. The results showed that calycosin dose-dependently inhibited 143B cell proliferation as reflected in tetrazolium salt (MTT) assay (P<0.01). In addition, calycosin effectively down-regulated cellular mRNA expressions of IκBα, NF-κB p65 and cyclin D1 through RT-PCR assay (P<0.01). Next, calycosin-mediated inhibitory effect on 143B tumor-bearing nude mice and the underlying mechanism were evaluated and discussed. As a result, calycosin administration significantly blocked solid tumor growth in 143B-harbored nude mice (P<0.01). Furthermore, intracellular Bcl-2 protein expression was effectively reduced in 143B-harbored tumor tissue through western blotting analysis (P<0.01), while intratumoral Apaf-1 and cleaved Caspase-3 protein levels were up-regulated, respectively (P<0.01). Taken together, calycosin possesses the anti-osteosarcoma potential, in which the mechanism involved was associated with activation of apoptotic, thus inducing apoptosis.