Chemosensitization of carmustine with maitake beta-glucan on androgen-independent prostatic cancer cells: involvement of glyoxalase I

J Altern Complement Med. 2002 Oct;8(5):573-80. doi: 10.1089/107555302320825084.


Objective: To improve the poor efficacy (< 10%) of chemotherapy for patients with hormone-refractory prostate cancer, we investigated a possible cytotoxic effect of carmustine/beta-glucan combination on prostatic cancer PC-3 cells, focusing on a glutathione-dependent detoxifying enzyme, glyoxalase I (Gly-I).

Methods: Carmustine (BCNU) is an anticancer agent and a putative inhibitor of Gly-I, while beta-glucan is a unique, nontoxic polysaccharide extracted from maitake mushrooms. The cytotoxic effects of BCNU or other anticancer agents with beta-glucan on PC-3 cells were assessed by cell-viability testing and Gly-I activity was measured using the spectrophotometric method.

Results: BCNU, 5-fluorouracil (5-FU), and methotrexate (MTX) were capable of inducing approximately a 50% reduction in cell viability at 72 hours, while etoposide, cisplatin, and mitomycin C were all ineffective. Only the combination of BCNU (50 micro ;mol) and beta-glucan (60 micro g/mL) exhibited an enhanced cytotoxicity with an approximate 90% cell viability reduction, but little improvement was seen with any combinations of 5-FU, MTX, or beta-glucon. Gly-I assays revealed that such a profound (approximately 90%) cell death was accompanied by an approximate 80% reduction in Gly-I activity by 6 hours.

Conclusion: This study demonstrates a sensitized cytotoxic effect of BCNU with beta-glucan in PC-3 cells, which was associated with a drastic (approximately 80%) inactivation of Gly-I. Therefore, the BCNU/beta-glucan combination may help to improve current treatment efficacy by targeting Gly-I, which appears to be critically involved in prostate cancer viability.

MeSH terms

  • Agaricales
  • Androgens / metabolism
  • Antineoplastic Agents, Alkylating / pharmacology*
  • Antineoplastic Combined Chemotherapy Protocols / pharmacology
  • Carmustine / pharmacology*
  • Cell Survival / drug effects
  • Dose-Response Relationship, Drug
  • Fluorouracil / pharmacology
  • Glucans / pharmacology*
  • Humans
  • In Vitro Techniques
  • Lactoylglutathione Lyase / drug effects
  • Lactoylglutathione Lyase / metabolism*
  • Male
  • Methotrexate / pharmacology
  • Prostatic Neoplasms / drug therapy*
  • Prostatic Neoplasms / enzymology*
  • Prostatic Neoplasms / metabolism
  • Tumor Cells, Cultured / drug effects
  • beta-Glucans*


  • Androgens
  • Antineoplastic Agents, Alkylating
  • Glucans
  • beta-Glucans
  • beta-1,6-glucan
  • Lactoylglutathione Lyase
  • Fluorouracil
  • Carmustine
  • Methotrexate