Crude Extracts of Agaricus brasiliensis Induce Apoptosis in Human Oral Cancer CAL 27 Cells through a Mitochondria-dependent Pathway

In Taiwan, oral cancer is the fourth leading cause of male cancer mortality, and is still increasing. The Basiodiomycete, Agaricus brasiliensis Mural (ABM) is a dietary mushroom and has been known for its immune-enhancing, antitumor, antioxidation, antiviral and anti-mutagenesis functions. However, the exact anticancer mechanisms of ABM on human oral cancer cells are still unclear. In the present study, we investigated the effects of 50% ethanol crude extracts and hot water extracts of ABM on oral cancer CAL 27 cells. We observed that 0.9 mg/ml and 0.7 mg/ml of ABM 50% ethanol crude extracts and hot water, respectively, caused morphological changes and significantly reduced cell viability after 48-h treatment. The results showed that both extracts of ABM inhibited cell proliferation, increased the Ca2+ release, reduced the mitochondria membrane potential (Delta Psi m), and caused cell cycle arrest in the G(0)/G(1) I phase, which contributed to apoptosis. Additionally, ABM induced DNA fragmentation, a characteristic of apoptosis and the expressions of apoptosis-related proteins, including apoptosis-inducing factor, cytochrome c, and caspase-3, were increased. Overall, we demonstrated that 50% ethanol crude extract and hot water extracts of ABM were able to induce apoptotic cell death in CAL 27 cells via the release of cytochrome c from mitochondria into the cytoplasm and activation of caspase-3 in vitro.