Induction of apoptosis in human hepatoma cells by mycelia of Antrodia camphorata in submerged culture

The effect of methanolic extracts of mycelia (MEM) from Antrodia camphorata (Polyporaceac, Aphyllophorales) of submerged culture (ACSC) on the inhibition of cell viability and the mechanism of MEM-induced cytotoxic in hepatoma cells were investigated. The IC(50) of MEM on the cytotoxicity of HepG2 (wild type p53) and Hep3B (delete p53) were 49.5 and 62.7 microg/ml, respectively, on 48 h incubation. There is no observable cytotoxicity of MEM in Chang liver cells and rat primary hepatocytes at the concentration of 100 microg/ml. Cell cycle analysis revealed that MEM induced apoptosis on HepG2 via G0/G1 cell cycle arrest. MEM (100 microg/ml) treated HepG2 and Hep3B for 72 h, the apoptotic cells were 98.3 and 39.5%, respectively. The activities of caspase-3, -8 and -9 in HepG2 induced by MEM (50 microg/ml) were increased 5.3, 6.7 and 2.2-fold, respectively. MEM-induced apoptotic cell death was accompanied by up-regulation of caspase-3 and -8 in HepG2 cells. Combined treatment with MEM and caspase-3, -8 and -9 inhibitors, the caspase-3 and -8 inhibitors were accounting for 63 and 47% inhibition in MEM-induced apoptosis, respectively; however, caspase-9 inhibitor exhibited no obvious inhibition effect on the apoptosis percentage (p>0.05). The results indicated that MEM induced HepG2 apoptosis through activation of caspase-3 and -8 cascades and regulation of the cell cycle progression to inhibit hepatoma cells proliferation.