CY Ho, CF Kim, KN Leung, KP Fung, TF Tse, H Chan, CB Lau.
School of Pharmacy, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
Coriolus versicolor (CV), also called Yunzhi, has been demonstrated to exert anti-tumor effects on various types of cancer cells, but the underlying mechanism has not been fully elucidated. The present study aimed to evaluate the in vitro anti-tumor activity of a standardized aqueous ethanol extract prepared from CV on four breast cancer cell lines using MTT assay, and test whether the mechanism involves apoptosis induction and modulation of p53 and Bcl-2 protein expressions using cell death detection ELISA, p53 and Bcl-2 ELISAs respectively. Our results demonstrated that the CV extract dose-dependently suppressed the proliferation of three breast tumor cell lines, with ascending order of IC50 values: T-47D, MCF-7, MDA-MB-231, while BT-20 cells were not significantly affected. Tumoricidal activity of the CV extract was found to be comparable to a chemotherapeutic anti-cancer drug, mitomycin C. Nucleosome productions in apoptotic MDA-MB-231, MCF-7 and T-47D cells were significantly augmented in a time-dependent manner and paralleled the anti-proliferative activity of CV extract. Expression of p53 protein was significantly upregulated only in T-47D cells treated with the CV extract in a dose- and time-dependent fashion, but not in MCF-7 (except at 400 mug/ml after 16 h) and MDA-MB-231 cells. The CV extract significantly induced a dose-dependent downregulation of Bcl-2 protein expression in MCF-7 and T-47D cells, but not in MDA-MB-231 cells. These results suggested that apoptosis induction, differentially dependent of p53 and Bcl-2 expressions, might be the possible mechanism of CV extract-mediated cytotoxicity in human breast cancer cells in vitro.
Breakspear Hospital, Hemel Hempstead, Herts, United Kingdom. jmonro@breakspearmedical.com
Cancer has been attributed to 3 causes: pollution, infection, and poor nutrition. Conventional treatments include surgery, chemotherapy, and radiotherapy. The author proposes that immunotherapy also be considered. Among other environmental influences, dietary deficiencies and carcinogenic viral infections must be investigated and treated wherever possible. It has been suggested that mushrooms, in particular, have a structure that is immunomodulatory because it resembles the proteoglycan structure in the human extracellular matrix, and both are metabolically active. Inasmuch as mitochondria have a bacterial origin, proteoglycans may have a mushroom origin. The author describes a study which shows that natural killer cells can double in number with 8 wk of treatment with Coriolus versicolor. Also described is an epidemiological survey of cancer deaths among Flammulina velutipes farmers in Japan, which found that the mushroom farmers had lower rates of cancer deaths than controls who were not involved in mushroom farming?
Department of Surgery II, Faculty of Medicine, Kyushu University Fukuoka, Japan.
Abstract
We evaluated the effects of chemotherapy given postoperatively with and without immunomodulators on the survival of patients who had undergone resection for gastric cancer. We conducted a retrospective survey of data on 963 Japanese patients treated at our department of surgery between 1965 and 1987. Data related to the duration of postoperative survival were calculated for those who received chemotherapy, i.e. an individualized combination of various agents given with or without the immunomodulators PSK, a protein extract of the fungus Coriolus versicolor, and/or OK-432, a preparation of an attenuated strain of Streptococcus (immunochemotherapy). Postoperative immunochemotherapy was more often prescribed for patients with advanced disease. The survival of patients who received immunochemotherapy was shorter than that of patients who received only chemotherapy. In a subgroup of patients adjusted for disease stage, the survival of those on chemotherapy versus immunochemotherapy did not differ significantly at any stage. For optimal results, a protocol for postoperative immunochemotherapy needs to be designed and investigated prospectively and according to the stage of gastric cancer. The stage III gastric cancers seem amenable to a favorable response.
Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Abstract
Polysaccharide peptide (PSP) is a protein-bound polysaccharide extracted from an edible mushroom, Coriolus versicolor. Effects of PSP (2g/kg/day) on cyclophosphamide (CPA, 40 mg/kg/2 days)-induced immunosuppression were investigated by determining lymphocyte proliferation, Natural killer (NK) cell formation, IgG and IL-2 concentration, WBC count and the weight of organs after rats were treated with or without CPA in the presence or absence of PSP. The results demonstrated that PSP possessed immunopotentiating effect, being effective in restoring CPA-induced immunosuppression such as depressed lymphocyte proliferation, Natural Killer cell function, production on white blood cell and the growth of spleen and thymus in rats as well as in increasing both IgG and IL-2 production on which CPA did not have significant effects under the conditions of our experiments. PSP can partly restore CPA-induced immunosuppression. Based on our findings and the data accumulated so far, it was suggested that PSP should be considered as an useful adjuvant especially combined with CPA or other chemotherapy in clinical treatment of cancer patients. The mechanism by which PSP restores the immunosuppression induced by CPA is unclear.
Department of Surgery II, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Abstract
A retrospective analysis of postoperative chemotherapy had shown the continuous administration of UFT, an oral preparation of 1-(2-tetrahydrofuryl)-5-fluorouracil (tegafur) and uracil at a molar ratio of 1:4, to be effective for poorly differentiated gastric cancer. We therefore sought to determine prospectively the effective dose of postoperative chemotherapy with UFT for patients with poorly differentiated gastric cancer following a curative resection. We determined the effect 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 differentiated stage II-IV gastric cancer were entered into this study after undergoing a curative resection. No differences 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-specific 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 differentiated gastric cancer, and is also cost-effective for outpatients.
Immunoceuticals can be considered as substances having immunotherapeutic efficacy when taken orally. More than 50 mushroom species have yielded potential immunoceuticals that exhibit anticancer activity in vitro or in animal models and of these, six have been investigated in human cancers. All are non-toxic and very well tolerated. Lentinan and schizophyllan have little oral activity. Active Hexose Correlated Compound (AHCC) is poorly defined but has shown early clinical promise. Maitake D-Fraction has limited proof of clinical efficacy to date, but controlled research is underway. Two proteoglycans from Coriolus versicolor – PSK (Polysaccharide-K) and PSP (Polysaccharide-Peptide – have demonstrated the most promise. In Japanese trials since 1970, PSK significantly extended survival at five years or beyond in cancers of the stomach, colon-rectum, esophagus, nasopharynx, and lung (non-small cell types), and in a HLA B40-positive breast cancer subset. PSP was subjected to Phase II and Phase III trials in China. In double-blind trials, PSP significantly extended five-year survival in esophageal cancer. PSP significantly improved quality of life, provided substantial pain relief, and enhanced immune status in 70-97 percent of patients with cancers of the stomach, esophagus, lung, ovary, and cervix. PSK and PSP boosted immune cell production, ameliorated chemotherapy symptoms, and enhanced tumor infiltration by dendritic and cytotoxic T-cells. Their extremely high tolerability, proven benefits to survival and quality of life, and compatibility with chemotherapy and radiation therapy makes them well suited for cancer management regimens.
Radiobiology Laboratory, St. Mary’s Medical Center, California Pacific Medical Center Research Institute, San Francisco 94118, USA.
Abstract
Polysaccharide-K (polysaccharide-Kureha; PSK), also known as krestin, is a unique protein-bound polysaccharide, which has been used as a chemoimmunotherapy agent in the treatment of cancer in Asia for over 30 years. PSK and Polysaccharopeptide (PSP) are both protein-bound polysaccharides which are derived from the CM-101 and COV-1 strains of the fungus Coriolus versicolor by Japanese and Chinese researchers, respectively. Both polysaccharide preparations have documented anticancer activity in vitro, in vivo and in human clinical trials, though PSK has been researched longer and has therefore undergone more thorough laboratory, animal and clinical testing. Several randomized clinical trials have demonstrated that PSK has great potential as an adjuvant cancer therapy agent, with positive results seen in the adjuvant treatment of gastric, esophageal, colorectal, breast and lung cancers. These studies have suggested the efficacy of PSK as an immunotherapy or biological response modifier (BRM). BRMs potentially have the ability to improve the “host versus tumor response,” thereby increasing the ability of the host to defend itself from tumor progression. The mechanisms of biological response modification by PSK have yet to be clearly and completely elucidated. Some studies suggest that PSK may act to increase leukocyte activation and response through up-regulation of key cytokines. Indeed, natural killer (NK) and lymphocyte-activated killer (LAK) cell activation has been demonstrated in vivo and in vitro, and recent genetic studies reveal increased expression of key immune cytokines in response to treatment with PSK. An antimetastatic action of PSK has also been demonstrated and is perhaps attributed to its potential to inhibit metalloproteinases and other enzymes involved in metastatic activity. PSK has also been shown to cause differentiation of leukemic cells in vitro, and this effect has been attributed to induction of differentiation cytokines. PSK has further been shown to have antioxidant capacity which may allow it to play a role as a normal tissue chemo- and radio-protector when used in combination with adjuvant or definitive chemotherapy and/or radiotherapy in the treatment of cancer, while it may also enable it to defend the host from oxidative stress. Interestingly, studies have also shown that PSK may actually inhibit carcinogenesis by inhibiting the action of various carcinogens on vulnerable cell lines. This action of PSK may play a role in preventing second primary tumors when an inducing agent, such as tobacco or asbestos, is suspected and may also prevent second malignancies due to the carcinogenic effects of radiotherapy and cytotoxic chemotherapy. Another very important aspect of chemoimmunotherapy, in general is that it may be used on debilitated patients such as those with AIDS and the elderly who might otherwise be denied potentially helpful adjuvant cytotoxic chemotherapy. Further determination of the mechanisms of these anti-cancer, immunostimulating and biological response modifying effects of PSK as well as of other protein-bound polysaccharides is certainly warranted. Indeed, with modern cellular and molecular biology techniques, a better understanding of the specific molecular effects of PSK on tumor cells as well as leukocytes may be determined. Much of the research that has been done on PSK is outlined in this paper and may serve as a foundation toward determining the mechanisms of action of this and other protein-bound polysaccharides in the treatment of cancer. This information may open new doors in the development of novel strategies for the treatment of malignancies using adjuvant immunotherapy in combination with surgery, chemotherapy and/or radiotherapy.
Institute of Technology and Engineering PN456, Massey University, Private Bag 11 222, 5320, Palmerston North, New Zealand.
Abstract
The protein-bound polysaccharides or polysaccharopeptides produced by Coriolus versicolor are effective immunopotentiators, which are used to supplement the chemotherapy and radiotherapy of cancers and various infectious diseases. Antitumor activity of polysaccharopeptides has been documented. Several kinds of protein-bound polysaccharides have been shown to be produced by the white rot fungus, C. versicolor. Although some of these polymers are structurally distinct, they are not distinguishable in terms of their physiological activity. This review focuses on the physiologically active polysaccharopeptides of C. versicolor. In nature, C. versicolor occurs as a mushroom body, but the fungus can be grown as mycelial biomass in submerged culture in bioreactors. Mushrooms gathered in the wild, cultivated mushrooms, and the mycelial biomass of submerged culture are used to produce the polysaccharopeptides. Submerged cultures are typically carried out in batches lasting 5-7 days and at 25-27 degrees C. Hot water extraction of the biomass is used to recover the thermostable polysaccharopeptides that are concentrated, purified, and dried into a powder for medicinal use. In view of the documented physiological benefits of these compounds, extensive research is underway on the structure, composition, production methods, and use of new C. versicolor strains for producing the therapeutic biopolymers. Properties, physiological activity, recovery, and purification of the bioactive polysaccharopeptides are discussed.
Breakspear Hospital, Hemel Hempstead, Herts, United Kingdom. jmonro@breakspearmedical.com
Abstract
Cancer has been attributed to 3 causes: pollution, infection, and poor nutrition. Conventional treatments include surgery, chemotherapy, and radiotherapy. The author proposes that immunotherapy also be considered. Among other environmental influences, dietary deficiencies and carcinogenic viral infections must be investigated and treated wherever possible. It has been suggested that mushrooms, in particular, have a structure that is immunomodulatory because it resembles the proteoglycan structure in the human extracellular matrix, and both are metabolically active. Inasmuch as mitochondria have a bacterial origin, proteoglycans may have a mushroom origin. The author describes a study which shows that natural killer cells can double in number with 8 wk of treatment with Coriolus versicolor. Also described is an epidemiological survey of cancer deaths among Flammulina velutipes farmers in Japan, which found that the mushroom farmers had lower rates of cancer deaths than controls who were not involved in mushroom farming.
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.