Pleurotus ostreatus inhibits proliferation and modulates expression of cell cycle regulatory proteins in human breast and colon cancer cells

Abstract

Oyster mushroom (Pleurotus ostreatus) is one of the edible mushrooms consumed in the US. The anticancer effects of P. ostreatus were demonstrated in vitro and in animal studies. However, the molecular mechanism(s) responsible for the biological activities of P. ostreatus remain to be elucidated. In the present study we evaluated the effect of an extract from Oyster mushroom (OME) on the proliferation of human breast and colon cancer cells. We found strong inhibitory effects of OME on the human colon cancer cells (HCT-116, HT-29) and breast cancer cells (MDA-MB-231, MCF-7) in a dose- and time-dependent manner. Interestingly, proliferation of non-tumorigenic colon (FHC) or mammary (MCF10A) epithelial cells was not affected by OME. Flow cytometry demonstrated that P. ostreatus induced cell cycle arrest at G0/G1 phase in colon HT-29 and breast MCF-7 cancer cells. cDNA microarray analysis revealed that OME changes expression of cell cycle regulatory proteins which expression was confirmed by western blot analysis. Therefore, our data demonstrate that OME induces cell cycle arrest of HT-29 by the up-regulation of expression of p-21, whereas cell cycle arrest of MCF-7 is induced by the up-regulation of expression of p-53 and p-21. In conclusion, our data suggest that the consumption of the dietary mushroom P. ostreatus could specifically inhibit growth of colon and breast cancer cells without any effect on normal cells.