Polysaccharide extracted from the Maitake mushroom (MP) is considered as a potential anticancer agent. The present study was performed to investigate the cytotoxic effects of MP and vitamin C (VC) alone and in combination on the viability of human neuroglioma M059 K cells in vitro. A combination of MP (1.0 mg/mL) and VC (0.4 mmol/L) led to a 53.10% reduction in cell viability and this treatment induced cell cycle arrest at the G2/M phase, and apoptosis occurred in 38.54% of the cells. Results of Hoechst 33258 staining and Western blot showed apoptotic cells appeared and changes in the expression of apoptosis-related proteins (upregulation of Bax and caspase-3, downregulation of Bcl-2, and activation of poly-(ADP-ribose)-polymerase). Moreover, the activities of caspase-3, caspase-8, and caspase-9 were enhanced in M059 K cells. The inhibiting effect of combined treatment with MP and VC on M059 K cells indicates the mechanism of anticancer activity involved induction of cell apoptosis.
Keywords: Maitake; antitumor; apoptosis; neuroglioma; vitamin C.