Agarol, an ergosterol derivative from Agaricus blazei, induces caspase-independent apoptosis in human cancer cells

Abstract

Agaricus blazei (A. blazei) is a mushroom with many biological effects and active ingredients. We purified a tumoricidal substance from A. blazei, an ergosterol derivative, and named it 'Agarol'. Cytotoxic effects of Agarol were determined by the MTT assay using A549, MKN45, HSC-3, and HSC-4 human carcinoma cell lines treated with Agarol. Apoptosis was detected by flow cytometry analysis. Reactive oxygen species (ROS) levels and mitochondria membrane potential (∆ψm) were also determined by flow cytometry. Western blot analysis was used to quantify the expression of apoptosis-related proteins. Agarol predominantly induced apoptosis in two p53-wild cell lines (A549 and MKN45) compared to the other p53-mutant cell lines (HSC-3 and HSC-4). Further mechanistic studies revealed that induction of apoptosis is associated with increased generation of ROS, reduced ∆ψm, release of apoptosis-inducing factor (AIF) from the mitochondria to the cytosol, upregulation of Bax, and downregulation of Bcl-2. Caspase-3 activities did not increase, and z-VAD-fmk, a caspase inhibitor, did not inhibit the Agarol-induced apoptosis. These findings indicate that Agarol induces caspase-independent apoptosis in human carcinoma cells through a mitochondrial pathway. The in vivo anticancer activity of Agarol was confirmed in a xenograft murine model. This study suggests a molecular mechanism by which Agarol induces apoptosis in human carcinoma cells and indicates the potential use of Agarol as an anticancer agent.

Genome Survey and Transcriptome Analysis on Mycelia and Primordia of Agaricus blazei

“…Nowadays, A. blazei has received great scientific and practical interest. A series of bioactive compounds, for instance polysaccharides [9,10], lectin [11,12], and ergosterol [13,14], have been discovered in A. blazei. Moreover, several volatile flavor ingredients have been identified in its fruiting body and mycelia [15].…”

A natural food ingredient based on ergosterol: optimization of the extraction fromAgaricus blazei, evaluation of bioactive properties and incorporation in yogurts

“…14,15 However, A. blazei also holds diverse small bioactive molecules, as the compound named agarol, an ergosterol derivative with anti-cancer and anti-tumor potential. 16 Although some studies have reported the optimization of ergosterol production using automated fermentative processes, 17,18 a considerable volume of A. blazei fruiting bodies that do not fit into the commercial standard, and therefore are usually discarded by the mushroom producers, could be feasibly exploited for this purpose. 1 Natural ingredients with antioxidant activity could be employed as substitutes for artificial additives, which might also display an important role in the prevention of various diseases related to oxidative/nitrosative stress, such as cancer, cardiovascular diseases and diabetes mellitus.…”

Autotrophic and Heterotrophic Growth Conditions Modify Biomolecole Production in the Microalga Galdieria sulphuraria (Cyanidiophyceae, Rhodophyta)

“…Ergosterol and derivatives have shown a wide range of health-promoting properties, such as antioxidant, anti-inflammatory, and antihyperlipidemic activities [40]. Treatments with ergosterol were able to significantly inhibit the proliferation of human epithelial type 2 (HEp-2) cells, a cell line originating from human laryngeal carcinoma, and the ergosterol derivatives were known to be a source of new potential antitumor or anti-angiogenesis chemotherapy agents [41]. Moreover, ergosterol derivatives have the ability to suppress lipopolysaccharide (LPS)-induced inflammatory responses of macrophages in vitro through the inhibition of highly proinflammatory cytokine (TNF-α) and cyclooxygenase-2 (COX-2) expression, as well as having a cytostatic effect on human colorectal adenocarcinoma cells [42].…”