Induction of autophagic cell death in human ovarian carcinoma cells by Antrodia salmonea through increased reactive oxygen species generation.

We reported in our previously executed studies that the fermented culture broth of Antrodia salmonea (AS), a mushroom used in Taiwanese folk medicine induced reactive oxygen species (ROS)-mediated apoptosis in human ovarian carcinoma cells. In this study, we studied the anticancer efficacies of AS (0-240 µg/ml) by examining the key molecular events implicated in cell death associated with autophagy in SKOV-3 and A2780 human ovarian carcinoma cells and clarified the fundamental molecular mechanisms. Treatment of ovarian carcinoma cells with AS-induced autophagic cell death mediated by increased microtubule-associated protein LC3-II, GFP-LC3 puncta, and acidic vesicular organelle (AVO) formation. These events are linked with the activation of p62/SQSTM1, the inhibition of ATG4B, the expression of ATG7, and the dysregulation of Beclin-1/Bcl-2 (i.e., B-cell lymphoma 2). N-acetylcysteine inhibited AS-induced ROS generation, which in turn constricted AS-induced LC3 conversion, AVO formation, and ATG4B inhibition, indicating ROS-mediated autophagy cell death. In addition, the 3-methyladenine (3-MA) or chloroquine (CQ)-induced autophagy inhibition decreased AS-induced apoptosis. Additionally, apoptosis inhibition by Z-VAD-FMK, a pan-caspase inhibitor, substantially suppressed AS-induced autophagy. Furthermore, AS-inhibited HER-2/ neu and PI3K/AKT signaling pathways which were reversed by autophagy inhibitors 3-MA and CQ. Thus, A. salmonea is a potential chemopreventive agent that is capable of activating ROS-mediated autophagic cell death in ovarian carcinoma cells.

Antrodia salmonea-induced oxidative stress abrogates HER-2 signaling cascade and enhanced apoptosis in ovarian carcinoma cells.

Antrodia salmonea is well known in Taiwan as a traditional Chinese medicinal fungus and has demonstrated antioxidant, anti-inflammatory, and anticancer effects. However, the anticancer activity of A. salmonea against human ovarian cancer is still elusive. Therefore, we investigated the antiovarian tumor activity of a fermented culture broth of A. salmonea and exhibits its underlying molecular mechanism. A. salmonea shows a significant effect on cell viability in human ovarian carcinoma (SKOV-3 or A2780) cell lines with an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Increased terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells and annexin V-propidium iodide stained cells indicate that A. salmonea induces late apoptosis in SKOV-3 cells. Notably, treatment with A. salmonea induced the following events: Apoptosis; caspase-3, -8, -9 and poly(ADP-ribose) polymerase activation; first apoptosis signal (Fas) and Fas ligand activation; Bid cleavage; and Bax2-B-cell lymphoma 2 dysregulation. The results show that A. salmonea-induced apoptosis was mediated by both mitochondrial and death receptor pathways. An increase in intracellular reactive oxygen species (ROS) was also observed in A. salmonea-treated cells, whereas the antioxidant N-acetylcysteine (NAC) prevented A. salmonea-induced cell death and DNA fragmentation, indicating that A. salmonea-induced apoptosis was mediated by ROS generation. Interestingly, A. salmonea-induced apoptosis is associated with the suppression of human epidermal growth factor receptor-2 (HER-2/neu) and phosphoinositide 3-kinase (PI3K)-protein kinase B (AKT) expression in HER-2/neu overexpressing SKOV-3 cells. NAC significantly prevented A. salmonea-induced HER-2/neu depletion and PI3K/AKT inactivation, indicating that A. salmonea-triggered apoptosis is mediated by ROS-inhibited HER-2/neu signaling cascades. To our knowledge, this is the first report describing the anticancer activity of this potentially beneficial mushroom against human ovarian carcinoma.

Induction of Nrf2-mediated genes by Antrodia salmonea inhibits ROS generation and inflammatory effects in lipopolysaccharide-stimulated RAW264.7 macrophages.

Antrodia salmonea (AS), a well-known medicinal mushroom in Taiwan, has been reported to exhibit anti-oxidant, anti-angiogenic, anti-atherogenic, and anti-inflammatory effects. In the present study, we investigated the activation of Nrf2-mediated antioxidant genes in RAW264.7 macrophages by the fermented culture broth of AS, studied the resulting protection against lipopolysaccharide (LPS)-stimulated inflammation, and revealed the molecular mechanisms underlying these protective effects. We found that non-cytotoxic concentrations of AS (25-100 µg mL⁻¹) protected macrophages from LPS-induced cell death and ROS generation in a dose-dependent manner. The antioxidant potential of AS was directly correlated with the increased expression of the antioxidant genes HO-1, NQO-1, and γ-GCLC, as well as the level of intracellular GSH followed by an increase in the nuclear translocation and transcriptional activation of the Nrf2-ARE pathway. Furthermore, Nrf2 knockdown diminished the protective effects of AS, as evidenced by the increased production of pro-inflammatory cytokines and chemokines, including PGE2, NO, TNF-α, and IL-1ß, in LPS-stimulated macrophages. Notably, AS treatment significantly inhibited LPS-induced ICAM-1 expression in macrophages. Our data suggest that the anti-inflammatory potential of Antrodia salmonea is mediated by the activation of Nrf2-dependent antioxidant defense mechanisms. Results support the traditional usage of this beneficial mushroom for the treatment of free radical-related diseases and inflammation.

The anti-tumor activity of Antrodia salmonea in human promyelocytic leukemia (HL-60) cells is mediated via the induction of G1 cell-cycle arrest and apoptosis in vitro or in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: The medicinal mushroom Antrodia salmonea has been used as a traditional Chinese medicine and has demonstrated antioxidant and anti-inflammatory effects. MATERIALS AND METHODS: In the present study, we examined the anti-tumor activity of the fermented culture broth of Antrodia salmonea (AS) in vitro and in vivo and revealed its underlying molecular mechanism of action. RESULTS: Treatment of human promyelocytic leukemia (HL-60) cells with AS (50-150 µg/mL) significantly reduced cell viability and caused G1 arrest via the inhibition of cell-cycle regulatory proteins, including cyclin D1, CDK4, cyclin E, cyclin A, and phosphorylated retinoblastoma protein (p-Rb). Furthermore, AS treatment induced apoptosis, which was associated with DNA fragmentation, followed by a sequence of events, including intracellular ROS generation; mitochondrial dysfunction; Fas ligand activation; cytochrome c release; caspase-3, -8, -9, and PARP activation; and Bcl-2/Bax dysregulation. The results of the in vitro study suggested that AS-induced apoptosis in HL-60 cells was mediated by both the mitochondrial and death receptor pathways. Furthermore, we found that AS treatment was effective in delaying tumor incidence in HL-60 xenografted nude mice and reducing tumor burden. CONCLUSIONS: To the best of our knowledge, this is the first report confirming the anti-tumor activity of this potentially beneficial mushroom against human promyelocytic leukemia.

Inhibition of Cell Growth and Induction of Apoptosis by Antrodia camphorata in HER-2/neu-Overexpressing Breast Cancer Cells through the Induction of ROS, Depletion of HER-2/neu, and Disruption of the PI3K/Akt Signaling Pathway.

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-3ß and ß-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.