Department of Zoology, The University of Hong Kong, Pokfalum Road, Hong Kong, SAR, P.R. China.
Abstract
The polysaccharide peptide (PSP) isolated from the mycelia of Chinese Medicinal fungus Coriolus versicolor has proven benefits in clinical trials in China but the mechanism of action has not been elucidated. In this study, HL-60 cell line was used to investigate the anti-proliferation and cell death process of PSP. The cytotoxicity of PSP on normal human T-lymphocytes was also evaluated. We show that PSP induced apoptosis of human promyelocytic leukemia HL-60 cells but not of normal human T-lymphocytes. The apoptotic machinery induced by PSP was associated with a decrease in Bcl-2/Bax ratio, drop in mitochondrial transmembrane potential, cytochrome c release, and activation of caspase-3, -8 and -9. Activation of the cellular apoptotic program is a current strategy for the treatment of human cancer, and the selectivity of PSP to induce apoptosis in cancerous and not on normal cells supports its development as a novel anticancer agent.
A retrospective analysis of postoperative chemotherapy had shown the continuous administration of UFT, an oral preparation of 1-(2-tetrahydrofuryl)-5-¯uorouracil (tegafur) and uracil at a molar ratio of 1:4, to be e€ective for poorly di€erentiated gastric cancer. We therefore sought to determine prospectively the effective dose of postoperative chemotherapy with UFT for patients with poorly di€erentiated gastric cancer following a curative resection. We determined the e€ect of the combined intravenous administration of mitomycin C (MMC) and oral treatment with protein-bound polysaccharide Kreha (PSK), extracted from the basidiomycete Coriolus versicolor, and UFT at a dose of either 8 mg/kg or 12 mg/kg daily for 1 year. A total of 224 patients with poorly di€erentiated stage II±IV gastric cancer were entered into this study after undergoing a curative resection. No di€erences were observed between the two treatment groups in terms of prognostic factors, the toxicity rate or the doses of the drugs prescribed, other than UFT. The higher dose of UFT in maintenance therapy led to a decrease in the recurrence rate (P < 0.05), and increases in disease-free survival and cause-speci®c survival (P < 0.05). UFT at 12 mg/ kg in postoperative chemotherapy was thus found- to improve the postoperative results with no increase in toxicity for poorly di€erentiated gastric cancer, and is also cost-e€ective for outpatients.
C.Y. Hoa, Clara B.S. Laua, C.F. Kima, K.N. Leungb, K.P. Fungb, T.F. Tsec, Helen H.L. Chanc, Moses S.S. Chowa
Being one of the commonly used Chinese medicinal herbs, Coriolus versicolor (CV), also named as Yunzhi, was known to possess both anti-tumor and immunopotentiating activities. The present study aimed to investigate the in vitro immunomodulatory effect of a standardized ethanol–water extract prepared from CV on the proliferation of murine splenic lymphocytes using the MTT assay, and the production of six T helper (Th)-related cytokines using the enzyme-linked immunosorbent assay (ELISA) technique. The results showed that the CV extract significantly augmented the proliferation of murine splenic lymphocytes in a time- and dose-dependent manner, maximally by 2.4-fold. Moreover, the production of two Th1-related cytokines, including interleukin (IL)-2 and IL-12, in culture supernatants from the CV extract-activated lymphocytes was prominently upregulated at 48 and 72 h. Positive correlations were found between the levels of these two cytokines and the MTT-based proliferative response. In contrast, the production of two other Th1-related cytokines, including interferon (IFN)-g and IL-18, was significantly augmented only at 24 h, but not at 48 and 72 h. On the other hand, the levels of two Th2-related cytokines such as IL-4 and IL-6 were undetectable in the culture supernatants of lymphocytes treated with the CVextract. The CVextract was suggested to be a lymphocyte mitogen by differentially enhancing the production of Th1-related cytokines.
Coriolus versicolor (CV), also known as Yunzhi, is one of the commonly used Chinese medicinal herbs. Although recent studies have demonstrated its antitumour activities on cancer cells in vitro and in vivo, the exact mechanism is not fully elucidated. Hence, the objective of this study was to examine the in vitro cytotoxic activities of a standardized aqueous ethanol extract prepared from Coriolus versicolor on a B-cell lymphoma (Raji) and two human promyelocytic leukemia (HL-60, NB-4) cell lines using a MTT cytotoxicity assay, and to test whether the mechanism involves induction of apoptosis. Cell death ELISA was employed to quantify the nucleosome production resulting from nuclear DNA fragmentation during apoptosis. The present results demonstrated that CV extract at 50 to 800 Ag/ml dose-dependently suppressed the proliferation of Raji, NB-4, and HL-60 cells by more than 90% (p < 0.01), with ascending order of IC50 values: HL-60 (147.3 F 15.2 Ag/ml), Raji (253.8 F 60.7 Ag/ml) and NB-4 (269.3 F 12.4 Ag/ml). The extract however did not exert any significant cytotoxic effect on normal liver cell line WRL (IC50 > 800 Ag/ml) when compared with a chemotherapeutic anticancer drug, mitomycin C (MMC), confirming the tumour-selective cytotoxicity. Nucleosome productions in HL-60, NB-4 and Raji cells were significantly increased by 3.6-, 3.6- and 5.6-fold respectively upon the treatment of CV extract, while no significant nucleosome production was detected in extract-treated WRL cells. The CV extract was found to selectively and dose-dependently inhibit the proliferation of lymphoma and leukemic cells possibly via an apoptosis-dependent pathway.
In the present study the anti-cancer effect of polysaccharide peptide of Coriolus versicolor Cov-1 (PSP) was compared with polysaccharide peptide of Coriolus versicolor CM-101 (PSK) on four human tumor cell line targets (SGC 7901, stomach cancer cell; SPC, human lung adenocarcinoma cell; SLY, human monocytic leukemia cell and Mei, human skin histiocytic lymphoma cell) in Vitro.
PSP had similar cytotoxic effects upon human tumor cells as PSK, both inhibiting cell growth. In comparison with control specimens, the SPC cell line treated with PSP (1000ug/ml) for 72 hours at 37oC showed marked morphological changes such as cell swelling, chromatin aggregation, formation of polynuclear cells and sawtooth on the surface of cell nuclei.
PSK as a new immunomodulative drug had been widely used for clinical anticancer therapy in Japan. When combined with chemotherapy, radiotherapy and surgical operation, PSK is found to be able to improve the therapeutic effects. In 1983, a polysaccharide peptide of Coriolus versicolor Cov-1 was isolated from the mycelia by Qing-yao Yang. It is possessed of physio-chemical characteristics similar to PSK and designated as PSP. In the present study the anti-cancer effect of PSP was compared with PSK using four human tumor cell line targets in vitro.
To elucidate the effects of PSK, a protein-bound polysaccharide from Coriolus versicolor, on gene expression in tumor cells, we prepared cDNA clone libraries from PSKtreated and untreated cells of a rat ascites hepatoma line, AH66, which was previously shown to be susceptible to the antitumor action of this compound. Two PSK-induced and one suppressed cDNA clones were selected from these libraries by using a differential colony hybridization and RNA blot hybridization. PSK was thus shown to have a direct effect on the transcription and consequently on the translation of tumor cells.
Full article: https://mushroomstudies.co/wp-content/uploads/2010/09/Cloning-of-sequences-induced-and-suppressed-by-administration-of-PSK-antitumor-protein-bound-polysaccharide.pdf
Suto T, Fukuda S, Moriya N, Watanabe Y, Sasaki D, Yoshida Y, Sakata Y.
We conducted a randomized, controlled trial comparing 5-fluorouracil (5-FU) with or without biological response modifiers (BRMs) as a maintenance therapy for hepatocellular carcinoma (HCC) after treatment with percutaneous ethanol injection (PEI), transcatheter arterial embolization (TAE) or arterial infusion of antitumor agents (AI). A total of 58 cases of HCC were classified into 4 groups as follows: group I, PSK with 5-FU (n = 15); group II, lentinan with 5-FU (n = 15); group III, OK-432 with 5-FU (n = 12); and group IV, 5-FU alone as the control (n = 16). The mean survival time, mortality rate, time to progression, and T4/T8 ratio of lymphocytes in the peripheral blood were compared among the four groups. There was no significant difference in the background factors among the groups. In group I, the T4/T8 ratio of lymphocytes was reduced after the therapy. No significant difference was found among the groups in terms of the mean survival time, mortality rate, or time to progression. PEI for initial therapy was superior to the other therapies in terms of the mean survival time and mortality rate. These results suggest that the addition of BRM to maintenance therapy with 5-FU exerts no prognostic benefit on HCC patients treated with PEI, TAE, or AI.
A randomized controlled study was carried out on curatively resected gastric cancer patients in a cooperative study involving 16 institutions in order to evaluate the effect of an alternative long-term adjuvant immunochemotherapy using Esquinon (CQ) and Krestin (PSK). One week after surgery, CQ was given at a dose of 2mg/m2 once a week for 3 weeks and this was repeated every 6 weeks. CQ was administered intravenously in the 1st course and thereafter orally up to 9 courses. Three postoperative week, immunotherapy was then started in which PSK was given orally in 3 divided doses of
2g/m2/day from the day when CQ therapy ended for 4 consecutive weeks, and this performed for every course. Estimated survival rate and cumulative survival curves were compared utilizing the data up to 7 years after surgery in the chemotherapy group given CQ alone and in the immunochemotherapy group given CQ + PSK. The survival curve in all cases showed a favorable form in the CQ + PSK group for up to 36 months, and thereafter it crossed with that of the CQ group for up to 68 months. Both curves twisted at 68 months and then deviated from each other, showing that the effect in the CQ + PSK group beneficial. The curve showed a twisting configuration throughout the treatment period. There was no statistically significant difference between the survival curves of the two groups. Retrospective survival analysis was then performed on separate subgroups classified into the category of S1, S2, N1, and N2. The CQ + PSK group was better than the CQ alone group in its survival rate for the S1 + S2 (N1-2) group, the percentage being 11.5%, and a statistically significant difference was observed between the two groups (p = 0.089).
The most effective treatment for gastric cancer is complete surgical resection with lymphadenectomy. However, a number of patients experience recurrence of the cancer even after curative surgery. This review focuses on comparative trials studying the use of adjuvant therapy with chemotherapy plus immunotherapy in the treatment of patients with curatively resected gastric cancer. Preoperative and intraperitoneal therapy, and therapy for advanced or recurrent gastric cancer are also discussed. At present, some subset analyses of adjuvant trials have shown favorable results suggesting that the biological response modifiers (BRMs), PSK or OK-432, add a benefit to chemotherapy. For advanced gastric cancer, although gastric cancer cells are generally not very sensitive to most of the currently available chemotherapeutic agents, it has been reported that biochemical modulation with treatments including low-dose cisplatin + 5-FU (fluorouracil) have high response rates and exert an immunomodulatory effect especially when used in combination with BRMs. The impact of splenectomy and some of the
promising newly developed drugs are discussed.
Up to now, the three main weapons against cancer have been surgery, radiotherapy and chemotherapy. Although these classical methods of treatment have given fairly good results in general, the results have yet to be improved, especially in late cases. Thus for many years, the search for a more effective means of anti-cancer treatment has been going on world-wide. An ideal drug would of course be one that could directly kill all the cancer cells without harming the normal tissues, and also without causing general toxicity. However, at present a more practical approach is to use drugs that would either enhance the biological effects of radiation or of cytotoxic agents, or strengthen the organism’s immunological defenses. In recent years, several such drugs have been undergoing clinical trials, for example, Misonidazole, RS 2508, OK-432, PSK, etc.