Finkelstein MP, Aynehchi S, Samadi AA, Drinis S, Choudhury MS, Tazaki H, Konno S. Chemosensitization of carmustine with maitake beta-glucan on androgen-independent prostatic cancer cells: involvement of glyoxalase I.
J Altern Complement Med 2002;
8:573-80. [PMID:
12470438 DOI:
10.1089/107555302320825084]
[Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
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.
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