Cytotoxic Effect of Oyster Mushroom Pleurotus ostreatus on Human Androgen-Independent Prostate Cancer PC-3 Cells

Abstract

Twenty species of edible mushrooms and three purified mushroom polysaccharides were screened for their antitumor potential on human androgen-independent cancer PC-3 cells. A water-soluble extract (POE) prepared from the fresh oyster mushroom Pleurotus ostreatus produced the most significant cytotoxicity on PC-3 cells among the mushroom species tested. At the same time, POE induced a rapid apoptosis on PC-3 cells detected with annexin V-fluorescein isothiocyanate flow cytometry when the cells were exposed to POE (150 microg/mL) for 2 hours. Induced apoptosis was also confirmed by DNA fragment terminal deoxynucleotidyl transferase-mediated X-dUTP nick end labeling staining while POE (200 microg/mL) was added to PC-3 cells for 6 hours. Both cytotoxicity and induced apoptosis mediated by POE in PC-3 cells are dose-dependent. Interestingly, PC-3 cells appeared to be more sensitive to POE in anchorage-independent growth condition. Tumor colony-forming efficiency was dramatically reduced to 4.5% or 0.5% in POE (60 or 120 microg/mL)-supplemented soft agar medium compared with that of POE-free medium (defined as 100%). Temperature in POE processing plays a decisive role for the cytotoxic activity. Bioactivity of POE was eliminated by exposure to high temperature (80 degrees C) for 2 hours; however, it remained stable at a series temperatures of below 40 degrees C. The active fraction POE-F2 was analyzed and identified by size exclusion of high performance liquid chromatography and the CellTiter 96 AQueous Cell Proliferation Assay (Promega, Madison, WI). Since POE-F2 is also sensitive to heat and has strong 280 nm absorption, the results imply that active compounds recovered from P. ostreatus are water-soluble proteins or polypeptides.

Anti‐Cancer Effects of Protein Extracts from Calvatia lilacina, Pleurotus ostreatus and Volvariella volvacea

“…Another study demonstrated that PO expresses marked antihepatoma and antisarcoma activities [21]. Treatment with the water extract of PO (150  μ g mL −1 ) induced phosphatidyl serine translocation from the inner membrane to the outer membrane after as little as 2 h and then induced apoptosis in human prostate cancer PC-3 cells [6]. Recently, the water-soluble polysaccharide extracted from the fruiting bodies of PO was shown to have obvious antitumor activity; they inhibited human HeLa cells in a concentration-dependent manner [11].…”

“…The extraction of PO suppresses the proliferation of breast and colon cancer cells via p53-dependent and p53-independent pathways [3]. The water-soluble polysaccharide of PO is capable of enhancing concanavalin A- or lipopolysaccharide-induced lymphocyte proliferation [4, 5] and induces apoptosis in human PC-3 androgen-independent cancer cells as well as human HT-29 colon cancer cells [6, 7]. DNA isolated from the fruit body of PO augmented NK cytotoxic activity in vitro and significantly increased the life span of mice with solid Ehrlich carcinoma [8].…”

Oyster Mushroom : Answer to Human Ailments:a Review

“…Extracts of Pleurotus species had higher antitumor activity toward lung cancer cells (A549). Recently, a potent antioxidant activity against both DPPH and ABTS radicals was detected in the ethanolic extracts of Pleurotus mushroom [73]. Many more reports are available indicating that oyster mushroom possesses antitumor activity of lectin isolated from P. citrinopileatus exerted potent antitumor activity in mice bearing sarcoma S-180.…”

Extracellular polysaccharide production by a strain of Pleurotus djamor isolated in the south of Brazil and antitumor activity on Sarcoma 180

“…Pleurotus sp. antitumor activity has been focused by several studies (Zhang et al , 2004; Gu and Sivam, 2006; Lavi et al , 2006; Sarangi et al , 2006; Jedinak and Sliva, 2008; Wolff et al , 2008; Dalonso et al , 2010). …”