Anti-Inflammatory Constituents of Antrodia camphorata on RAW 264.7 Cells Induced by Polyinosinic-Polycytidylic Acid.

Antrodia camphorata is an endemic mushroom in Taiwan. This study was designed to screen anti-inflammatory compounds from the methanolic extract of the mycelium of A. camphorata on nitric oxide (NO) production in RAW 264.7 cells induced by polyinosinic-polycytidylic acid (poly I:C), a synthetic analog of double-stranded RNA (dsRNA) known to be present in viral infection. A combination of bioactivity-guided isolation with an NMR-based identification led to the isolation of 4-acetylantroquinonol B (1), along with seven compounds. The structure of new compounds (4 and 5) was elucidated by spectroscopic experiments, including MS, IR, and NMR analysis. The anti-inflammatory activity of all isolated compounds was assessed at non-cytotoxic concentrations. 4-Acetylantroquinonol B (1) was the most potent compound against poly I:C-induced NO production in RAW 264.7 cells with an IC50 value of 0.57 ± 0.06 µM.

Application of Multiple Strategies to Improve the Production of the Potential Cancer Drug 4-Acetylantroquinonol B (4-AAQB) by the Rare Fungus Antrodia cinnamomea.

4-Acetylantroquinonol B (4-AAQB) was identified in the rare fungus Antrodia cinnamomea and has been proven to be a potential therapeutic agent for cancer treatment. But the extraction of 4-AAQB from the fruit body led to a low yield and limited its further application in the pharmaceutical field. In this work, 4-AAQB production was enhanced in the submerged fermentation by the combination of exogenous additives, surfactants with the in situ extractive fermentation. 4-Methylbenzoic acid was proven to be an efficient additive for the accumulation of 4-AAQB by Antrodia cinnamomea, while 2% (w/v) Tween-80 added on the first day as surfactant and 30% (w/v) oleic acid added on the sixteenth day as extractant were the most available couples for 4-AAQB production in the in situ extractive fermentation. The combination of these multiple strategies resulted in the yield of 4-AAQB to 17.27 mg/g dry cell weight with a titer of 140 mg/L, which was the highest titer of 4-AAQB reported so far. It showed that the combination of these strategies had a significant promotion on 4-AAQB production by A. cinnamomea, which laid a good foundation for its large-scale production and also provided a viable method for the cultivation of other rare fungi.

4-Acetylantroquinonol B enhances cell death and inhibits autophagy by downregulating the PI3K/Akt/MDR1 pathway in gemcitabine-resistant pancreatic cancer cells.

Gemcitabine (GEM) is a typical chemotherapeutic drug used to treat pancreatic cancer, but GEM resistance develops within weeks after chemotherapy. Hence, the development of a new strategy to overcome drug resistance is urgent. 4-Acetylantroquinonol B (4-AAQB), a ubiquinone derived from Taiwanofungus camphoratus, has hepatoprotective, anti-obesity, and antitumor activities. However, the role of 4-AAQB in enhancing GEM sensitivity is unclear. This study aimed to determine the underlying mechanisms by which 4-AAQB enhances cytotoxicity and GEM sensitivity. Cell viability was dramatically reduced by 4-AAQB (2 and 5 µM) treatment in the MiaPaCa-2 and GEM-resistant MiaPaCa-2 (MiaPaCa-2GEMR) human pancreatic cancer cells. 4-AAQB led to cell cycle arrest, upregulated the levels of reactive oxygen species (ROS), promoted apoptosis, and inhibited autophagy, which subsequently enhanced GEM chemosensitivity by suppressing the receptor for advanced glycation end products (RAGE)/high mobility group box 1 (HMGB1)-initiated PI3K/Akt/multidrug resistance protein 1 (MDR1) signaling pathway in both cell lines. Vascular endothelial growth factor A (VEGFA) expression, cell migration, and invasion were also inhibited by the 4-AAQB incubation. Overall, this combination treatment strategy might represent a novel approach for GEM-resistant pancreatic cancer.

4-Acetylantroquinonol B ameliorates nonalcoholic steatohepatitis by suppression of ER stress and NLRP3 inflammasome activation.

OBJECTIVE: Nonalcoholic fatty liver disease (NAFLD) is an inflammatory lipotoxic disorder with a prevalence of over 25% worldwide. However, safe and effective therapeutic agents for the management of NAFLD are still lacking. We aimed to investigate the hepatoprotective effect and molecular mechanism of 4-acetylantroquinonol B (4-AAQB), a natural ubiquinone derivative obtained from the mycelia of Antrodia cinnamomea. METHODS: RAW264.7 and J774A.1 cells were treated with 4-AAQB and then stimulated with LPS or tunicamycin (TM) for 24 h. Inflammatory responses, markers of endoplasmic reticulum (ER) stress, and NOD-like receptor protein 3 (NLRP3) inflammasome were analyzed in both cell lines. In the applied in vivo model, male C57BL/6J mice were fed with chow or a methionine/choline-deficient (MCD) diet along with vehicle or 4-AAQB (10 mg/kg, i.p. injected, once a day) for 10 consecutive days. Plasma levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured. Liver tissues were analyzed using histological techniques; protein levels involved in ER stress, NLRP3 inflammasome, and inflammatory responses were measured. RESULTS: 4-AAQB significantly ameliorated the plasma levels of ALT and AST as well as the NAFLD activity score (NAS) in mice fed the MCD diet. In addition, 4-AAQB suppressed inflammatory responses, ER stress, and NLRP3 inflammasome activation, but increased the nuclear factor erythroid 2-related factor 2 (Nrf2) and Sirtuin 1 (SIRT1) signaling pathways in both in vitro and in vivo models. CONCLUSIONS: We suggest that 4-AAQB treatment might be a tangible therapeutic strategy in the management of NAFLD/NASH.

4-Acetylantroquinonol B Inhibits Osteoclastogenesis by Inhibiting the Autophagy Pathway in a Simulated Microgravity Model.

Astronauts suffer from 1-2% bone loss per month during space missions. Targeting osteoclast differentiation has been regarded as a promising strategy to prevent osteoporosis in microgravity (µXg). 4-acetylantroquinonol B (4-AAQB), a ubiquinone from Antrodia cinnamomea, has shown anti-inflammatory and anti-hepatoma activities. However, the effect of 4-AAQB on µXg-induced osteoclastogenesis remains unclear. In this study, we aimed to explore the mechanistic impact of 4-AAQB on osteoclast formation under µXg conditions. The monocyte/macrophage-like cell line RAW264.7 was exposed to simulated µXg (Rotary Cell Culture System; Synthecon, Houston, TX, USA) for 24 h and then treated with 4-AAQB or alendronate (ALN) and osteoclast differentiation factor receptor activator of nuclear factor kappa-B ligand (RANKL). Osteoclastogenesis, bone resorption activity, and osteoclast differentiation-related signaling pathways were analyzed using tartrate-resistant acid phosphatase (TRAP) staining, actin ring fluorescent staining, bone resorption, and western blotting assays. Based on the results of TRAP staining, actin ring staining, and bone resorption assays, we found that 4-AAQB significantly inhibited µXg-induced osteoclast differentiation. The critical regulators of osteoclast differentiation, including nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), c-Fos, and dendritic cell-specific transmembrane protein (DC-STAMP), were consistently decreased. Meanwhile, osteoclast apoptosis and cell cycle arrest were also observed along with autophagy suppression. Interestingly, the autophagy inhibitors 3-methyladenine (3-MA) and chloroquine (CQ) showed similar effects to 4-AAQB. In conclusion, we suggest that 4-AAQB may serve as a potential agent against µXg-induced osteoclast formation.

4-Hydroxybenzoic acid serves as an endogenous ring precursor for antroquinonol biosynthesis in Antrodia cinnamomea.

Antrodia cinnamomea, an endemic fungus species of Taiwan, has long been used as a luxurious dietary supplement to enhance liver functions and as a remedy for various cancers. Antroquinonol (AQ), identified from the mycelium of A. cinnamomea, is currently in phase II clinical trials in the USA and Taiwan for the treatment of non-small-cell lung cancer. In the previous studies, we have demonstrated that AQ and 4-acetylantroquinonol B (4-AAQB) utilize orsellinic acid, via polyketide pathway, as the ring precursor, and their biosynthetic sequences are similar to those of coenzyme Q. In order to test 4-hydroxybenzoic acid (4-HBA), synthesized via shikimate pathway, is the ring precursor of AQ analogs, the strategy of metabolic labeling with stable isotopes was applied in this study. Here we have confirmed that 4-HBA serves as the ring precursor for AQ but not a precursor of 4-AAQB. Experimental results indicated that A. cinnamomea preferentially utilizes endogenous 4-HBA via shikimate pathway for AQ biosynthesis. Exogenous tyrosine and phenylalanine can be utilized for AQ biosynthesis when shikimate pathway is blocked by glyphosate. The benzoquinone ring of 4-AAQB is synthesized only via polyketide pathway, but that of AQ is synthesized via both polyketide pathway and shikimate pathway. The precursor-products relationships diagram of AQ and 4-AAQB in A. cinnamomea are proposed based on the experimental findings.

4-Acetylantroquinonol B suppresses autophagic flux and improves cisplatin sensitivity in highly aggressive epithelial cancer through the PI3K/Akt/mTOR/p70S6K signaling pathway.

Targeting residual self-renewing, chemoresistant cancerous cells may represent the key to overcoming therapy resistance. The entry of these quiescent cells into an activated state is associated with high metabolic demand and autophagic flux. Therefore, modulating the autophagy pathway in aggressive carcinomas may be beneficial as a therapeutic modality. In this study, we evaluated the anti-tumor activities of 4-acetylantroquinonol B (4-AAQB) in chemoresistant ovarian cancer cells, particularly its ability to modulate autophagy through autophagy-related genes (Atg). Atg-5 was overexpressed in invasive ovarian cancer cell lines and tissue (OR: 5.133; P=0.027) and depleting Atg-5 in ES-2 cell lines significantly induced apoptosis. 4-AAQB effectively suppressed viability of various subtypes of ovarian cancer. Cells with higher cisplatin-resistance were more responsive to 4-AAQB. For the first time, we demonstrate that 4-AAQB significantly suppress Atg-5 and Atg-7 expression with decreased autophagic flux in ovarian cancer cells via inhibition of the PI3K/Akt/mTOR/p70S6K signaling pathway. Similar to Atg-5 silencing, 4-AAQB-induced autophagy inhibition significantly enhanced cell death in vitro. These results are comparable to those of hydroxychloroquine (HCQ). In addition, 4-AAQB/cisplatin synergistically induced apoptosis in ovarian cancer cells. In vivo, 4-AAQB/cisplatin also significantly induced apoptosis and autophagy in an ES-2 mouse xenografts model. This is the first report demonstrating the efficacy of 4-AAQB alone or in combination with cisplatin on the suppression of ovarian cancer via Atg-5-dependent autophagy. We believe these findings will be beneficial in the development of a novel anti-ovarian cancer therapeutic strategy.

Biosynthesis of Antroquinonol and 4-Acetylantroquinonol B via a Polyketide Pathway Using Orsellinic Acid as a Ring Precursor in Antrodia cinnamomea.

Antroquinonol (AQ) and 4-acetylantroquinonol B (4-AAQB), isolated from the mycelium of Antrodia cinnamomea, have a similar chemical backbone to coenzyme Q (CoQ). Based on the postulation that biosynthesis of both AQ and 4-AAQB in A. cinnamomea starts from the polyketide pathway, we cultivated this fungus in a culture medium containing [U-13C]oleic acid, and then we analyzed the crude extracts of the mycelium using UHPLC-MS. We found that AQ and 4-AAQB follow similar biosynthetic sequences as CoQ. Obvious [13C2] fragments on the ring backbone were detected in the mass spectrum for [13C2]AQ, [13C2]4-AAQB, and their [13C2] intermediates found in this study. The orsellinic acid, formed from acetyl-CoA and malonyl-CoA via the polyketide pathway, was found to be a novel benzoquinone ring precursor for AQ and 4-AAQB. The identification of endogenously synthesized farnesylated intermediates allows us to postulate the routes of AQ and 4-AAQB biosynthesis in A. cinnamomea.

4-Acetylantroquinonol B inhibits colorectal cancer tumorigenesis and suppresses cancer stem-like phenotype.

4-Acetylantroquinonol B (4-AAQB), closely related to the better known antroquinonol, is a bioactive isolate of the mycelia of Antrodia camphorata, a Taiwanese mushroom with documented anti-inflammatory, hypoglycemic, vasorelaxative, and recently demonstrated, antiproliferative activity. Based on its traditional use, we hypothesized that 4-AAQB may play an active role in the suppression of cellular transformation, tumor aggression and progression, as well as chemoresistance in colorectal carcinoma (CRC). In this study, we investigated the antiproliferative role of 4-AAQB and its underlying molecular mechanism. We also compared its anticancer therapeutic potential with that of antroquinonol and the CRC combination chemotherapy of choice - folinic acid, fluorouracil and oxaliplatin (FOLFOX). Our results showed that 4-AAQB was most effective in inhibiting tumor proliferation, suppressing tumor growth and attenuating stemness-related chemoresistance. 4-AAQB negatively regulates vital oncogenic and stem cell maintenance signal transduction pathways, including the Lgr5/Wnt/ß-catenin, JAK-STAT, and non-transmembrane receptor tyrosine kinase signaling pathways, as well as inducing a dose-dependent downregulation of ALDH and other stemness related factors. These results were validated in vivo, with animal studies showing 4-AAQB possessed comparable tumor-shrinking ability as FOLFOX and potentiates ability of the later to reduce tumor size. Thus, 4-AAQB, a novel small molecule, projects as a potent therapeutic agent for monotherapy or as a component of standard combination chemotherapy.