Antrodia camphorata grown on germinated brown rice inhibits HT-29 human colon carcinoma proliferation through inducing G0/G1 phase arrest and apoptosis by targeting the β-catenin signaling.

Antrodia camphorata (AC) has been used as a traditional medicine to treat food and drug intoxication, diarrhea, abdominal pain, hypertension, pruritis (skin itch), and liver cancer in East Asia. In this study, we investigated anticancer activities of AC grown on germinated brown rice (CBR) in HT-29 human colon cancer cells. We found that the inhibitory efficacy of CBR 80% ethanol (EtOH) extract on HT-29 and CT-26 cell proliferation was more effective than ordinary AC EtOH 80% extract. Next, 80% EtOH extract of CBR was further separated into four fractions; hexane, ethyl acetate (EtOAc), butanol (BuOH), and water. Among them, CBR EtOAc fraction showed the strongest inhibitory activity against HT-29 cell proliferation. Therefore, CBR EtOAc fraction was chosen for further studies. Annexin V-fluorescein isothiocyanate staining data indicated that CBR EtOAc fraction induced apoptosis. Induction of G0/G1 cell cycle arrest on human colon carcinoma cell was observed in CBR EtOAc fraction-treated cells. We found that CBR decreased the level of proteins involved in G0/G1 cell cycle arrest and apoptosis. CBR EtOAc fraction inhibited the β-catenin signaling pathway, supporting its suppressive activity on the level of cyclin D1. High performance liquid chromatography analysis data indicated that CBR EtOAc fraction contained adenosine. This is the first investigation that CBR has a greater potential as a novel chemopreventive agent than AC against colon cancer. These data suggest that CBR might be useful as a chemopreventive agent against colorectal cancer.