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


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.


CONCLUSIONS
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.
Fullerton
S A
SA
Department of Urology, New York Medical College, Valhalla, New York 10595, USA.
Samadi
A A
AA
Tortorelis
D G
DG
Choudhury
M S
MS
Mallouh
C
C
Tazaki
H
H
Konno
S
S
D000363:Agaricales; D000728:Androgens / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects*; D001205:Ascorbic Acid / Q000633:toxicity; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005936:Glucans / Q000633:toxicity*; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D011471:Prostatic Neoplasms; D014407:Tumor Cells, Cultured
D000728:Androgens; D000970:Antineoplastic Agents; D005936:Glucans; D001205:Ascorbic Acid