Induction of apoptosis in osteosarcoma S180 cells by polysaccharide from Dictyophora indusiata.

Polysaccharides have shown great importance in cancer therapy. The current study showed that a polysaccharide from Dictyophora indusiata (PDI) also possessed anti-cancer properties. Methyl thiazolyl tetrazolium assay revealed a dose-dependent reduction of osteosarcoma S180 growth in response to PDI treatment. Apoptosis was observed following treatments with PDI, as reflected by the appearance of the subdiploid fraction and DNA fragmentations. We then investigated effects of PDI on expression of apoptosis-associated genes and the results revealed an increase of expression of bcl-2 and decreases of cdk4 and p53 protein levels. Finally, PDI treatment significantly increased the activation of caspase-3, a key executioner of apoptosis. These findings indicate that PDI may act as a chemopreventive and/or chemotherapeutic agent in osteosarcoma cells by reducing cell viability and inducing apoptosis.