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November 2010

Improved recovery of myelosuppression following chemotherapy in mice by combined administration of PSK and various cytokines.

Granulocyte-colony-stimulating factor (G-CSF), granulocyte/macrophage-colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) were used in combination with PSK, a protein-bound polysaccharide extracted from mycelium of Coriolus versicolor (strain CM101), in myelosuppressed mice. The myelosuppression model consisted of BDF1 mice who received 150 mg/kg 5-fluorouracil (5-FU) intravenously. The peripheral blood leukocyte count during the recovery stage was significantly increased when these cytokines were administered with PSK compared to when the cytokines were used individually. In vitro colony assay revealed that the combination of PSK and any of GM-CSF, IL-3 or stem cell factor (SCF) showed a greater increase in colony numbers than when these materials were administered individually, although G-CSF did not show a synergistic effect with PSK. When bone marrow cells were obtained from mice which had been given PSK or IL-3, the colony assays were made in the presence of PSK or IL-3 in vitro. The greatest increase in the numbers was observed in colonies of the cultured group in the presence of IL-3 after the PSK priming. However, the colony formation potential of PSK was not inhibited by addition of anti-SCF antibody. The above results indicate that the combined administration of PSK with G-CSF, GM-CSF or IL-3 increased the hematological recovery of myelosuppressed mice. Moreover, the phase at which PSK has effects on hematopoietic cells seems to be at a more immature level than with IL-3. The combined administration of PSK and the above cytokines may improve myelosuppression after chemotherapy in patients with malignancy.[…]

Enhancement of anti-cancer activity of cisdiaminedichloroplatinum by the protein-bound polysaccharide of Coriolus versicolor QUEL (PS-K) in vitro.

The protein-bound polysaccharide of Coriolus versicolor QUEL (PS_K) expresses superoxide dismutase (SOD) mimicking activity. Examination was made of the effects of PS-K on cancer cell lines following administration of the anti-cancer drug cisdiaminedichloroplatinum (cisplatin). Cell proliferation of each cell line was inhibited markedly by cisplatin from 0.5 to 5 micrograms/0.5 ml per well. Fifty percent of the inhibitory concentration (IC50) was 0.33 micrograms/0.5 ml per well in NRK-49F and human ovarian cancer cells, and 1.5 micrograms/0.5 ml per well in H4-II-E. PS-K 50 micrograms/0.5 ml per well prevented cytotoxicity due to cisplatin toward NRK-49F, but enhanced the cytotoxicity on H4-II-E and human ovarian cancer cells. Increase in lipid peroxide and decrease in SOD activity were observed following an IC50 dose of cisplatin. With PS-K 50 micrograms/0.5 ml per well, all the above were augmented in H4-II-E and ovarian cancer cells, but diminished in NRK-49F cell line. PS-K may have effect on cancer patients through its combining with cisplatin.[…]

Oxidative stress relief for cancer-bearing hosts by the protein-bound polysaccharide of Coriolus versicolor QUEL with SOD mimicking activity.

The protein-bound polysaccharide of Coriolus versicolor QUEL (PS-K) expresses the mimetic activity of superoxide dismutase (SOD). Human cancer patients usually suffer from oxidative stress (OS). Examination was made to determine the capacity of this drug with SOD mimetic activity for relieving OS. Rats transplanted with Walker 256 fibrosarcoma showed OS on day 12. After confirming high levels of OS on day 13, PS-K50 mg/kg was intraperitoneally administered, and prompt decrease in O2-release from RBC was noted. The drug ceased to have any effect 24 hours following the first inoculation. Average OS in human cancer patients was found twice that in healthy persons. In human cancer patients perorally administered PS-K3.0 g/day, OS decreased to the normal level one day after the initial administration. Plasma lipid peroxide (LPO) in cancer patients treated with PS-K for 28 days increased and withdrawal of the drug led to decreased LPO.[…]

Suppression of cancer cell growth in vitro by the protein-bound polysaccharide of Coriolus versicolor QUEL (PS-K) with SOD mimicking activity.

The protein-bound polysaccharide of Coriolus versicolor QUEL (PS-K) expresses the mimicking activity of superoxide dismutase (SOD). Examination was made of the suppressive effects of PS-K on cancer cell lines cultured in vitro. The SOD activity of LLC-WRC-256 (Walker 256 fibrosarcoma) cell lines was less than that of NRK-49F (rat normal kidney fibroblast), H4-II-E (rat hepatoma) and H4-II-E-C3 (rat hepatoma) cell lines. This activity in Walker 256 fibrosarcoma cells increased by 3.6 times and H2O2 concentration, by 2.56 times by PS-K 500 micrograms/ml. Cell proliferation was consequently suppressed and living cells decreased to less than 50% of the cells cultured without PS-K. Catalase and glutathione peroxidase activity changed little by PS-K. The sensitivity of cancer cells to PS-K can be predetermined based on SOD activity in tumor tissue.[…]