Purification of a novel protein with cytotoxicity against non‐small‐cell lung cancer cells from Boletus bicolor

Abstract

A novel protein (D1 component) was purified from Boletus bicolor by ion‐exchange chromatography and gel chromatography on a HiTrap™ Q HP column, a diethylaminoethanol cellulose‐52 column, and a Sephadex G75 column, respectively. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis revealed that the D1 component was a single protein band with a molecular weight of about 40 kDa. The sulforhodamine B assay showed that at concentrations as low as 25–75 μg/ml, protein D1 significantly inhibited the proliferation of human lung adenocarcinoma cell lines (A549 and H1299 cells) and had little effect on human normal kidney cells (HEK293 cells). After labeling protein D1, it was found that D1 could enter the cytoplasm of tumor cells and colocated with lysosomes. Flow cytometry results demonstrated that protein D1 induced apoptosis and G1 phase arrest of the cell cycle in A549 and H1299 cells. The Western blot analysis results showed that the expression of apoptosis and cell cycle‐related proteins of cleaved caspase‐3, cytochrome c, Bax, P16, and P21 was significantly upregulated, whereas the expression of Bcl‐2, CDK4, cyclin D, p‐Rb, and E2F was significantly downregulated after treatment with protein D1. Therefore, D1 exhibits potential to be developed into an antitumor agent.

Ultrasound-assisted extraction optimization of polyphenols from Boletus bicolor and evaluation of its antioxidant activity

“…Boletus bicolor is a basidiomycete mushroom species widely used as delicacy food, and its extract is traditionally used to treat several human ailments (14,15). As a kind of delicious wild mushroom, B. bicolor contains various beneficial components, including steroids, terpenoids, alkaloids, phenols, and proteins, and has many beneficial properties, such as enhancing human immunity, anti-tumor, antioxidant, and antibacterial (16,17). To the best of our knowledge, the antioxidant activities obtained from wild edible fungal B. bicolor extracts were rarely explored, so effective extraction of polyphenols from B. bicolor should be helpful for its utilization.…”