Agaricus blazei (class Basidiomycotina) aqueous extract enhances the expression of c-Jun protein in MCF7 cells

The edible mushroom Agaricus blazei Murill is considered a health food in many countries after it was reported to be a source of antitumor and immunoactive compounds. An aqueous extract (AE) from this basidiomycete significantly enhanced the expression of the c-Jun/activator protein-1 (AP1) in the human breast cancer cell line MCF7. Incubating the cells with 17-beta-estradiol (E2), p-nonylphenol (NP), and the AE combined, or NP plus the AE, resulted in increased cell proliferation compared to the untreated control by 93 and 67%, respectively. However, incubating the cells with the extract alone did not enhance cell division. It is suggested that the enhanced proliferation of MCF7 cells in the presence of NP and the AE may be due to the involvement of an AP1 gene regulatory complex. This is the first report showing enhanced c-Jun/AP1 expression in MCF7 cells incubated with an aqueous fungal extract.