[#2000-05] Induction of apoptosis in human prostatic cancer cells with β-glucan (Maitake mushroom polysaccharide), S.A. Fullerton et al.

Induction of apoptosis in human prostatic cancer cells with β-glucan (Maitake mushroom polysaccharide)

Fullerton SA, Samadi AA, Tortorelis DG, Choudhury MS, Mallouh C, Tazaki H, Konno S.

Department of Urology, New York Medical College

PURPOSE: To explore more effective treatment for hormone-refractory prostate cancer, we investigated the potential antitumor effect of β-glucan, a polysaccharide of the Maitake mushroom, on prostatic cancer cells in vitro.

MATERIALS AND METHODS: Human prostate cancer PC-3 cells were treated with various concentrations of the highly purified beta-glucan preparation Grifron-D(R) (GD), and viability was determined at 24 h. Lipid peroxidation (LPO) assay and in situ hybridization (ISH) were performed to unravel the antitumor mechanism of GD.

RESULTS: A dose-response study showed that almost complete (>95%) cell death was attained in 24 h with GD > or = 480 μg/mL. Combinations of GD in a concentration as low as 30 to 60 μg/mL with 200 μM vitamin C were as effective as GD alone at 480 μg/mL, inducing >90% cytotoxic cell death. Simultaneous use with various anticancer drugs showed little potentiation of their efficacy except for the carmustine/GD combination (approximately 90% reduction in cell viability). The significantly (two fold) elevated LPO level and positive ISH staining of GD-treated cells indicated oxidative membrane damage resulting in apoptotic cell death.

CONCLUSION: A bioactive beta-glucan from the Maitake mushroom has a cytotoxic effect, presumably through oxidative stress, on prostatic cancer cells in vitro, leading to apoptosis. Potentiation of GD action by vitamin C and the chemosensitizing effect of GD on carmustine may also have clinical implications. Therefore, this unique mushroom polysaccharide may have great a potential as an alternative therapeutic modality for prostate cancer.