Induction of apoptosis in cultured cells by extracts from shiitake (Lentinula edodes) mycelial culture broth

Extracts fromshiitake (Lentinula edodes) mycelial culture broth, by an organic solvent ethyl acetate, inhibited the proliferation of cultured cells. At lower concentrations (1.25–15 μg/ml), this inhibition, measured by the MTT assay, was dose- and cell line-dependent. Inhibition of tumor cells, such as Caski, SiHa, HeLa, HP-1 and A375, byL. edodes-436 extracts was stronger than inhibition of normal cells (3T3). At 20 μg/ml, the extracts induced changes in cell shape, DNA-fragmentation and the activation of caspase-3. The extracts also inhibited the binding of E2F protein to its promoter. The results suggest that extracts ofL. edodes culture broth contain substances that have the ability to induce apoptosis in the cultured cells.