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

Mol Urol. Spring 2000;4(1):7-13.

Abstract

Purpose: To explore more effective treatment for hormone-refractory prostate cancer, we investigated the potential antitumor effect of beta-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 microg/mL. Combinations of GD in a concentration as low as 30 to 60 microg/mL with 200 microM vitamin C were as effective as GD alone at 480 microg/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 (twofold) 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.

MeSH terms

  • Agaricales*
  • Androgens / pharmacology
  • Antineoplastic Agents / toxicity*
  • Apoptosis / drug effects*
  • Ascorbic Acid / toxicity
  • Cell Division / drug effects
  • Cell Survival / drug effects*
  • Dose-Response Relationship, Drug
  • Glucans / toxicity*
  • Humans
  • Lipid Peroxidation / drug effects
  • Male
  • Prostatic Neoplasms
  • Tumor Cells, Cultured

Substances

  • Androgens
  • Antineoplastic Agents
  • Glucans
  • Ascorbic Acid