Antrodia salmonea induces G2 cell-cycle arrest in human triple-negative breast cancer (MDA-MB-231) cells and suppresses tumor growth in athyrnic nude mice

Ethnopharmacological relevance: Antrodia salmonea (AS), is a well-known folk medicinal mushroom in Taiwan, has been reported to exhibit anti-oxidant, anti-angiogenic, and anti-inflammatory effects. Materials and methods: In the present study, we examined the effects of AS on cell-cycle arrest in vitro in MDA-MB-231 cells and on tumor regression in vivo using an athymic nude mice model. Results: AS (0-200 mu g/mL) treatment significantly induced G(2) cell-cycle arrest in MDA-MB-231 cells by reducing the levels of cyclin B1, cyclin A, cyclin E, and CDC2 proteins. In addition, N-acetylcysteine (NAC) pretreatment prevented AS induced G(2) cell-cycle arrest, indicating that ROS accumulation and subsequent cell cycle arrest might be a major mechanism of AS-induced cytotoxicity. Further, AS treatment decreased COX-2 expression and induced PARP cleavage was significantly reversed by NAC pretreatment in MDA-MB-231 cells. The in vivo study results revealed that AS treatment was effective in terms of delaying the tumor incidence and reducing the tumor growth in MDA-MB-231-xenografted nude mice. TUNEL assay, immunohistochemical staining and Western blotting confirmed that AS significantly modulated the xenografted tumor progression as demonstrated by induction of apoptosis, autophagy, and cell-cycle arrest. Conclusion: Our data strongly suggest that Antrodia salmonea could be an anti-cancer agent for human breast cancer.