Antitumor Effects of Extract of the Oak Bracket Medicinal Mushroom, Phellinus baumii (Agaricomycetes), on Human Melanoma Cells A375 In Vitro and In Vivo.

Melanoma is among the most aggressive and treatment-resistant human cancers. Phellinus baumii, a famous medicinal mushroom, has been used to treat different diseases, including cancer, in China and other east Asian countries. The purpose of this research was to explore its anticancer effects against melanoma, and the mechanisms that might be involved. CCK-8 assay exhibited that extracts of Ph. baumii (EPB) strongly inhibited cell viability of A375 melanoma cancer cell. Typical morphological changes of cell apoptosis were observed in EPB-treated A375 cells in Hoechst staining assay. Flow cytometry analysis indicated that EPB significantly induced A375 cells apoptosis and the cell cycle was disrupted in S phase. EPB increased the expression of Bax, and decreased Bcl-2 in A375 cells. EPB remarkably caused mitochondrial membrane potential collapse and induced a mitochondrial-dependent apoptosis in A375 cells evidenced by caspase-3 activation, followed by PARP cleavage. More importantly, EPB has shown a strong inhibitory effect on the migration and aggression of the A375 cells through the healing of the wound and transwell assay. In vivo, EPB was also found to strongly inhibit the growth of tumors in BALB/c nude mice. Our results indicated that Ph. baumii might be a natural therapeutic product for aggressive melanoma because it could induce apoptosis and inhibit metastasis in A375 cells.