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Antimetastatic
effects of PSK (Krestin), a protein-bound polysaccharide obtained from
basidiomycetes: an overview
Kobayashi H, Matsunaga K, Oguchi Y
Health Science University of Hokkaido, Japan
PSK, a protein-bound polysaccharide obtained from cultured mycelia of
Coriolus versicolor in basidiomycetes, is a biological response modifier,
diverse operations of which include an antitumor action.
We have previously reviewed recent research which had demonstrated that in
animals, PSK has a preventive effect on chemical carcinogen-induced,
radiation-induced, and spontaneously developed carcinogenesis (Kobayashi et al.,
Cancer Epidemiol., Biomarkers & Prev., 2: 271-276, 1993).
We now focus on the effects of PSK once the progression of carcinogenesis has
begun, and review what is now known of the preventive action of PSK on cancer
metastasis.
Recent research reports that PSK suppresses pulmonary metastasis of
methylcholanthrene-induced sarcomas, human prostate cancer DU145M, and lymphatic
metastasis of mouse leukemia P388, and that it has prolonged the survival period
in spontaneous metastasis models.
PSK also suppresses the metastasis of rat hepatoma AH60C, mouse colon cancer
colon 26, and mouse leukemia RL male 1 in artificial metastasis models.
PSK influences the steps of cancer metastasis in a number of ways:
(a) by suppression of intravasation through the inhibition of tumor invasion,
adhesion and production of cell matrix-degrading enzymes;
(b) by suppression of tumor cell attachment to endothelial cells through the
inhibition of tumor cell-induced platelet aggregation;
(c) by suppression of tumor cell migration after extravasation through the
inhibition of tumor cell motility; and
(d) by suppression of tumor growth after extravasation through the inhibition of
angiogenesis, the modulation of cytokine production, and the augmentation of
effector cell functions.
In addition, PSK has suppressed the malignant progression of mouse tumor cells
through superoxide trapping.
(ABSTRACT TRUNCATED AT 250 WORDS)
PMID:
7606203 [PubMed - indexed for MEDLINE]
Source:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7606203&dopt=Abstract
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