Inhibition of Cell Growth and Induction of Apoptosis by Antrodia camphorata in HER-2neu-Overexpressing Breast Cancer Cells through the Induction of ROS, Depletion of HER-2neu, and Disruption of the PI3KAkt Signaling Pathway

Abstract EN

Previously, we demonstrated that a submerged fermentation culture of Antrodia camphorata (AC) promotes cell-cycle arrest and apoptosis in human estrogen receptor-positive/negative breast cancer cells.

However, whether AC is effective against HER-2/neu-overexpressing breast cancers has not been thoroughly elucidated.

In the present study, we showed that AC exhibited a significant cytotoxic effect against HER-2/neu-overexpressing MDA-MB-453 and BT-474 cells.

Immunoblot analysis demonstrated that HER-2/neu and their tyrosine phosphorylation were inhibited by AC in a dose-dependent manner.

An increase in intracellular reactive oxygen species (ROS) was observed in AC-treated cells, whereas antioxidant N-acetylcysteine (NAC) significantly prevented AC induced HER-2/neu depletion and cell death, which directly indicates that AC-induced HER-2/neu depletion and cell death was mediated by ROS generation.

Also, AC significantly downregulated the expression of cyclin D1, cyclin E, and CDK4 followed by the suppression of PI3K/Akt, and their downstream effectors GSK-3β and β-catenin.

Notably, AC-treatment induced apoptotic cell death, which was associated with sub-G1 accumulation, DNA fragmentation, mitochondrial dysfunction, cytochrome c release, caspase-3/-9 activation, PARP degradation, and Bcl-2/Bax dysregulation.

Assays for colony formation also confirmed the growth-inhibitory effects of AC.

This is the first report confirming the anticancer activity of this potentially beneficial mushroom against human HER-2/neu-overexpressing breast cancers.