Mushroom Albatrellus Confluens Research Articles

Anticancer potential of grifolin in lung cancer treatment through PI3K/AKT pathway inhibition

ObjectiveGrifolin is a natural secondary metabolite isolated from edible fruiting bodies of the mushroom Albatrellus confluens. Grifolin has antitumor activities in several types of cancer. We aimed to determine the effects of grifolin on lung cancer. MethodsWe determined the proliferation, migration, invasion, and apoptosis of lung cancer cells using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Ethynyl deoxyuridine, colony formation, wound scratch, transwell, flow cytometry, and xenograft mouse assays. Molecular docking evaluated the binding relation between grifolin and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA). The levels of PIK3CA, AKT, and p-AKT were measured by western blot. ResultsGrifolin (10, 20, or 40 μM) inhibited the proliferation, migration, and invasion of lung cancer cells, and induced cell cycle arrest and apoptosis. Grifolin also decreased CDK4, CDK6, and CyclinD1 expression and significantly decreased PIK3CA and p-AKT expression in lung cancer cells. These anticancer effects were abolished by 740Y-P. ConclusionsGrifolin regulates the PI3K/AKT pathway, thus inhibiting lung cancer progression.

The Mushroom Albatrellus confluens: A Minireview on Phytochemistry, Biosynthesis, Synthesis and Pharmacological Activities.

Albatrellus confluens is one of the representative species in the Polyporaceae family. Its major mero terpenoid grifolin and related compounds have the potential for drug applications. The current study aims to briefly provide an insightful view of the phytochemistry, biosynthesis, synthesis, and pharmacology of A. confluens metabolites. Data collection was performed using electronic resources, e.g., Google Scholar, PubMed, and Sci-Finder from the 1990s to the present, while Albatrellus confluens is the most meaningful keyword in the search for publications. The Latin name Albatrellus confluens (Alb. & Schwein.) Kotl. & Pouzar is in accordance with the name listing on www.mycobank.org. By chromatography column procedures, it indicated that A. confluens species was associated with the presence of 57 secondary metabolites, in which nitrogenous compounds, meroterpenoids, polyene pyrones, and polyesters can be seen as the main phytochemical classes. L-isoleucine was the parent molecule in biosynthetic and synthetic steps of A. confluens nitrogenous compounds. Numerous experiments revealed that A. confluens isolated compounds have a variety of pharmacological activities, such as anticancer, anti-inflammatory, vasorelaxant, and neuroprotective and skin whitening activities. Some isolates become potential cancer inhibitors. Grifolin induced apoptosis and promoted cell cycle arrest in A2780 ovarian cancer cells via the inactivation of the ERK1/2/Akt signaling pathway. Grifolic acid caused osteosarcoma cancer cell deaths by inhibiting NADH generation and ATP production without obvious toxicity. Neoalbaconol caused apoptosis and necroptosis in mice bearing nasopharyngeal C666-1 cancer cells via PDK1-PI3K/Akt signaling inhibition. The continuation of chromatographic separation and biomedical research is expected. Modern biological assays for explaining the pharmacological values of A. confluens constituents are warranted. Toxicological and pharmacokinetic assessments are urgently needed.

Heterocyclic Compounds from the Mushroom Albatrellus confluens and Their Inhibitions against Lipopolysaccharides-Induced B Lymphocyte Cell Proliferation.

Eight hetereocyclic compounds conflamides B-I with an unprecedented skeleton and their precursor conflamide A were isolated from the mushroom Albatrellus confluens. Their structures and absolute configurations were determined by use of NMR studies, total synthesis, and calculated ECD spectra. Conflamides D and E were found to exhibit potent inhibition against LPS-induced B lymphocyte cell proliferation with IC50 values 1.48 and 5.71 μM, respectively.

Albatredines A and B, a pair of epimers with unusual natural heterocyclic skeletons from edible mushroom Albatrellus confluens.

A chemical study of the common species Albatrellus confluens present in Yunnan province, southwest China led to the identification of a pair of epimers named albatredines A (1) and B (2). They feature a natural unprecedented 1,2,4-oxadiazolidin-5-one skeleton. The acyl substitution pattern and complete configurational assignments were deduced from the comparison between experimental and theoretical 13C NMR and ECD data, respectively. Bioassay results showed that compound 1 exhibited a weak immunosuppressive activity against the concanavalin A-induced T lymphocyte cell proliferation (IC50 2.99 μM).

Grifolic acid induces mitochondrial membrane potential loss and cell death of RAW264.7 macrophages.

Grifolic acid is a phenolic compound that was first extracted from the mushroom Albatrellusconfluens; it acts as an agonist of the free fatty acid receptor (FFAR4). FFAR4 is expressed in macrophages and mediates the anti‑inflammatory effects of n‑3 unsaturated free fatty acids. In the present study, the effects of grifolic acid on macrophages were observed in mouse RAW264.7 cells. It was demonstrated that grifolic acid (2.5‑20µmol/l) treatment reduced RAW264.7 cell viability in a dose‑ and time‑dependent manner. The number of apoptotic cells significantly increased following grifolic acid treatment compared with the untreated control cells. Grifolic acid treatment resulted in a significant decrease in cellular adenosine 5'‑triphosphate (ATP) content in RAW264.7 cells. Mitochondrial membrane potential (MMP), as measured by JC‑1 staining, was significantly diminished by grifolic acid treatment in a dose‑ and time‑dependent manner. Treatment with cyclosporine A, a protector of MMP, attenuated grifolic acid‑induced reduction of MMP and viability in RAW264.7 cells. FFAR4 knockdown did not significantly influence grifolic acid‑induced reduction of cell viability, ATP levels or MMP. In conclusion, grifolic acid may induce macrophage cell death by reducing MMP and by inhibiting ATP production probably in an FFAR4‑independent manner.

Grifolin exhibits anti-cancer activity by inhibiting the development and invasion of gastric tumor cells.

Grifolin, a natural product isolated from the mushroom Albatrellus confluens, has been reported to be a potent anti-cancer agent in nasopharyngeal carcinoma and osteosarcoma. The data obtained in this study revealed that grifolin is capable of inhibiting the growth and invasion of gastric cancer cells by inducing apoptosis and suppressing the ERK1/2 pathway. Our results support the potent utility of grifolin as an anti-tumor lead compound against gastric cancer cells.

Grifolin inhibits tumor cells adhesion and migration via suppressing interplay between PGC1α and Fra-1 / LSF- MMP2 / CD44 axes.

Grifolin, a farnesyl phenolic compound isolated from the fresh fruiting bodies of the mushroom Albatrellus confluens, exhibits effective antitumor bioactivity in previous study of our group and other lab. In this study, we observed that grifolin inhibited tumor cells adhesion and migration. Moreover, grifolin reduced reactive oxygen species (ROS) production and caused cellular ATP depletion in high-metastatic tumor cells. PGC1α (Peroxisome proliferator-activated receptor γ, coactivator 1α) encodes a transcriptional co-activator involved in mitochondrial biogenesis and respiration and play a critical role in the maintenance of energy homeostasis. Interestingly, grifolin suppressed the mRNA as well as protein level of PGC1α. We further identified that MMP2 and CD44 expressions were PGC1α inducible. PGC1α can bind with metastatic-associated transcription factors: Fra-1 and LSF and the protein-protein interaction was attenuated by grifolin treatment. Overall, these findings suggest that grifolin decreased ROS generation and intracellular ATP to suppress tumor cell adhesion/migration via impeding the interplay between PGC1α and Fra-1 /LSF-MMP2/CD44 axes. Grifolin may develop as a promising lead compound for antitumor therapies by targeting energy metabolism regulator PGC1α signaling.

Grifolin directly targets ERK1/2 to epigenetically suppress cancer cell metastasis.

Grifolin, a secondary metabolite isolated from the fresh fruiting bodies of the mushroom Albatrellus confluens, has been reported by us and others to display potent antitumor effects. However, the molecular target of grifolin has not been identified and the underlying mechanism of action is not fully understood. Here, we report that the ERK1/2 protein kinases are direct molecular targets of grifolin. Molecular modeling, affinity chromatography and fluorescence quenching analyses showed that grifolin directly binds to ERK1/2. And in vitro and ex vivo kinase assay data further demonstrated that grifolin inhibited the kinase activities of ERK1/2. We found that grifolin suppressed adhesion, migration and invasion of high-metastatic cancer cells. The inhibitory effect of grifolin against tumor metastasis was further confirmed in a metastatic mouse model. We found that grifolin decreased phosphorylation of Elk1 at Ser383, and the protein as well as the mRNA level of DNMT1 was also down-regulated. By luciferase reporter and ChIP assay analyses, we confirmed that grifolin inhibited the transcription activity of Elk1 as well as its binding to the dnmt1 promoter region. Moreover, we report that significant increases in the mRNA levels of Timp2 and pten were induced by grifolin. Thus, our data suggest that grifolin exerts its anti-tumor activity by epigenetic reactivation of metastasis inhibitory-related genes through ERK1/2-Elk1-DNMT1 signaling. Grifolin may represent a promising therapeutic lead compound for intervention of cancer metastasis, and it may also be useful as an ERK1/2 kinase inhibitor as well as an epigenetic agent to further our understanding of DNMT1 function.

The role of targeting kinase activity by natural products in cancer chemoprevention and chemotherapy (Review).

The WHO clearly identifies tumors as a curable or a chronic disease. The use of natural agents in cancer prevention and therapy is currently playing an important role. Our laboratory has been investigating various natural phenolic compounds, including grifolin, neoalbaconol and epigallocatechin-3-gallate (EGCG). In the present review, we focus on the anticancer activities and the molecular mechanisms of these compounds. Grifolin, a secondary metabolite isolated from the mushroom Albatrellus confluens, has been shown to inhibit cell growth and induce cell cycle arrest in multiple cancer cell lines by targeting extracellular signal-regulated kinase 1 or by upregulating death-associated protein kinase 1 (DAPK1) via p53. We also demonstrated that neoalbaconol, a novel small-molecular compound with a drimane-type sesquiterpenoid structure obtained from Albatrellus confluens, regulates cell metabolism by targeting 3-phosphoinositide-dependent protein kinase 1 (PDK1) and inhibits cancer cell growth. EGCG, a well known catechin found in tea, has gained much attention for its anticancer effects. Previously, we found that it regulates EBV lytic infection through the phosphoinositide-3 kinase/Akt (PI3K/Akt) and mitogen-activated protein kinase (MAPK) pathways in EBV-positive cancer cells. Therefore, these natural agents could be used as potential leading compounds in the prevention of tumor progression and/or EBV-related cancer.

DAPK1 mediates the G1 phase arrest in human nasopharyngeal carcinoma cells induced by grifolin, a potential antitumor natural product

Grifolin, a secondary metabolite isolated from the fresh fruiting bodies of the mushroom Albatrellus confluens, has been shown to induce G1 phase cell-cycle arrest in tumor cells in previous studies of our group. However, the mechanisms of action are not completely understood. Our group further demonstrated that grifolin upregulates death-associated protein kinase 1 (DAPK1) in nasopharyngeal carcinoma cells (NPCs). Here, we found that grifolin induced dephosphorylation of DAPK1 (Ser308) to activate DAPK1 and subsequent phosphorylation of its potential downstream effector p21 (Thr145) in nasopharyngeal carcinoma cell CNE1. Inhibition of DAPK1 by introducing siRNA targeting DAPK1 reversed the grifolin- induced phosphorylation of p21. Furthermore, we confirmed that grifolin increased the half-life of p21 and promoted its stability. Flow cytometry analysis demonstrated that DAPK1 was involved in grifolin-induced G1 phase arrest in CNE1 cells. The similar effects induced by grifolin and mechanism beneath were identified in another nasopharyngeal carcinoma cell HONE1. In addition, we observed that grifolin promoted the protein-protein interaction of DAPK1 and ERK1/2 to prevent ERK1/2 nucleolus translocation. Our findings indicate that DAPK1 plays a crucial role in the induction of cell-cycle arrest at G1 phase by grifolin. Grifolin might represent a promising candidate in the prevention and intervention of cancer by targeting DAPK1 signaling to induce cell cycle G1 phase arrest.

Grifolin, a potent antitumour natural product upregulates death-associated protein kinase 1 DAPK1 via p53 in nasopharyngeal carcinoma cells

Grifolin, a secondary metabolite isolated from the fresh fruiting bodies of the mushroom Albatrellus confluens, has been shown to inhibit the growth of some cancer cell lines in vitro by induction of apoptosis in previous studies of our group. However, the mechanisms of action are not completely understood. An apoptosis-related gene expression profiling analysis provided a clue that death-associated protein kinase 1 ( dapk1) gene was upregulated at least twofold in response to grifolin treatment in nasopharyngeal carcinoma cell CNE1. Here, we further investigated the role of DAPK1 in apoptotic effect induced by grifolin. We observed that protein as well as mRNA level of DAPK1 was induced by grifolin in a dose-dependent manner in nasopharyngeal carcinoma cell CNE1. We found that grifolin increased both Ser392 and Ser20 phosphorylation levels of transcription factor p53 protein, which could promote its transcriptional activity. Moreover, induced by grifolin, the recruitment of p53 to dapk1 gene promoter was confirmed to enhance markedly using EMSA and ChIP assays analysis. The involvement of DAPK1 in grifolin-induced apoptosis was supported by the studies that introducing siRNA targeting DAPK1 to CNE1 cells remarkably interfered grifolin-caused apoptotic effect as well as the activation of caspase-3. Grifolin induced upregulation of DAPK1 via p53 was also observed in tumour cells derived from human breast cancer and human colon cancer. The findings suggest that upregulation of DAPK1 via p53–DAPK1 pathway is an important mechanism of grifolin contributing to its ability to induce apoptotic effect. Since growing evidence found a significant loss of DAPK1 expression in a large variety of tumour types, grifolin may represent a promising candidate in the intervention of cancer via targeting DAPK1.

Albaconol, a Plant-Derived Small Molecule, Inhibits Macrophage Function by Suppressing NF-κB Activation and Enhancing SOCS1 Expression

Discovery and functional identification of plant-derived small compounds as the immunosuppressant attract much attention these years. Albaconol is a new kind of small compound, prenylated resorcinol, isolated from the fruiting bodies of the inedible mushroom Albatrellus confluens. Our previous studies showed that albaconol can inhibit tumor cell growth and dendritic cell maturation. However, the immunomodulatory roles and the underlying mechanisms of albaconol have not been fully understood. In this study we investigated the effects of albaconol on the proliferation and LPS-induced proinflammatory cytokine production of macrophages. Albaconol, when used at a dose higher than 1.0 microg/ml, inhibited proliferation of RAW264.7 cells in a dose- and time-dependent manner, and could induce cellular apoptosis when used at high dosage (>or= 7.5 microg/ml). Furthermore, we found that albaconol used at a lower dosage without apoptosis induction could significantly inhibit LPS-induced TNF-alpha, IL-6, IL-1beta and NO production in RAW264.7 cells. The inhibition of NF-kappaB activation and enhancement of SOCS1 expression in LPS-stimulated macrophages by albaconol may contribute to the above immunosuppressive or anti-inflammatory activities of albaconol. Our results suggest that albaconol may be a potential immunosuppressive and anti-inflammatory drug.

Plant-derived small molecule albaconol suppresses LPS-triggered proinflammatory cytokine production and antigen presentation of dendritic cells by impairing NF-κB activation

Dendritic cells (DCs) play crucial roles in linking innate immunity and adaptive immunity, thus being regarded as one of the important targets of immunosuppressant. Natural small molecule products isolated from plants, such as fungal metabolites, have been shown to be effective in the treatment of cancer, inflammation and autoimmune diseases. Albaconol is a new kind of prenylated resorcinols isolated from the fruiting bodies of the inedible mushroom Albatrellus confluens, and has been shown to inhibit tumor cell growth. Considering that most of small molecule compounds with antitumor activity always exert immunosuppressive effect, so we wonder whether albaconol could inhibit maturation and antigen presentation of DCs, thus acting as immunosuppressant. Here we demonstrate that albaconol significantly inhibits LPS-induced production of proinflammatory cytokines TNF-alpha, IL-6, IL-1beta, and expression of MHC-II and co-stimulatory molecules by DCs. Furthermore, albaconol markedly inhibits T cell-stimulating capacity of DCs and DCs-initiated antigen-specific T cell response, indicating albaconol can inhibit phenotypic and functional maturation of DCs. Inhibition of LPS-induced NF-κB activation may contribute to the above immunosuppressive or anti-inflammatory activities of albaconol. Therefore, our results suggest that natural small molecule albaconol may be a potential immunosuppressive and anti-inflammatory agent through suppressing DCs function via impairment of NF-κB activation.

Grifolin, a potential antitumor natural product from the mushroom Albatrellus confluens, induces cell-cycle arrest in G1 phase via the ERK1/2 pathway

Grifolin, a natural product isolated from the mushroom Albatrellus confluens, has been shown to inhibit the growth of some cancer cell lines and induce significant apoptosis. However, the molecular targets and the signaling mechanism underlying the anticancer effect of this compound are not completely understood. Here, we undertook a gene expression profiling study to identify novel targets of grifolin. We found that the effect of grifolin on the human nasopharyngeal carcinoma cell line CNE1 occurs primarily via the ERK1/2 pathway. At high doses, both the ERK1/2 and the ERK5 pathways may be involved in the inhibition. Because inhibition of the ERK1/2 or the ERK5 pathway has been associated with cell-cycle arrest and growth inhibition, we evaluated the cell cycle distribution after grifolin treatment. We found that grifolin significantly caused cell-cycle arrest in G1 phase. To investigate the underlying mechanisms, G1-related proteins were assayed by Western blotting. Following grifolin treatment, a concomitant inhibition of cyclin D1, cyclin E, CDK4 expression, and subsequent reduction in pRB phosphorylation occurred. Meanwhile, grifolin treatment also resulted in a significant upregulation of CKI (p19 INK4D). These results suggest that the inhibition of the ERK1/2 or the ERK5 pathway is responsible for at least part of the induction of cell-cycle arrest in G1 phase by grifolin. These results are significant in that they provide a mechanistic framework for further exploring the use of grifolin as a novel antitumor agent.

Grifolin induces apoptosis via inhibition of PI3K/AKT signalling pathway in human osteosarcoma cells

Grifolin, a natural biologically active substance isolated from the edible bodies of the mushroom Albatrellus confluens, has been shown to inhibit proliferation and induce apoptosis in several cancer cell lines. But the mechanisms remain poorly understood. In this study, we investigated the apoptosis-inducing effects and the mechanisms of grifolin on human osteosarcoma cells. Our results demonstrated that grifolin induced concentration- and time-dependent suppression of proliferation and induction of apoptosis in U2OS and MG63 osteosarcoma cell lines. Grifolin induced the release of cytochrome c accompanied by activation of caspase-9, caspase-3 and cleavage of poly (ADP-ribose) polymerase (PARP). In addition, z-VAD-fmk, a universal inhibitor of caspases, prevented caspase-3 activation and PARP cleavage and inhibted grifolin-induced cell growth inhibition. Furthermore, grifolin treatment resulted in a reduction in level of phosphorylated AKT, FOXO transcription factor, and glycogen synthase kinase 3 (GSK3). Knockdown of GSK3 with siRNA inhibited the apoptotic effects of grifolin. On the other hand, grifolin treatment down-regulated the expression of the inhibitor of apoptosis protein(IAP) in both osteosarcoma cells. Taken together, our results suggested that grifolin is able to suppress the phosphorylation of Akt and its substrates FOXO transcription factor and GSK3 in osteosarcoma cells causing the suppression of proliferation and induction of mitochondria- and caspase-dependent apoptosis.

Grifolin, a potential antitumor natural product from the mushroom Albatrellus confluens, inhibits tumor cell growth by inducing apoptosis in vitro

Grifolin is a natural biologically active substance isolated from the fresh fruiting bodies of the mushroom Albatrellus confluens. Here, for the first time, we describe a novel activity of grifolin, namely its ability to inhibit the growth of tumor cells by the induction of apoptosis. Grifolin strongly inhibited the growth of tumor cell lines: CNE1, HeLa, MCF7, SW480, K562, Raji and B95-8. Analysis of acridine orange (AO)/ethidium bromide (EB) staining and flow cytometry showed that grifolin possessed apoptosis induction activity to CNE1, HeLa, MCF7 and SW480. Furthermore, the cytochrome c release from mitochondria was detected by confocal microscopy in CNE1 cells after a 12 h treatment with grifolin. The increase of caspase-8, 9, 3 activities revealed that caspase was a key mediator of the apoptotic pathway induced by grifolin, and the underexpression of Bcl-2 and up-regulation of Bax resulted in the increase of Bax: Bcl-2 ratio, suggesting that Bcl-2 family involved in the control of apoptosis. Owing to the combination of the significant antitumor activity by inducing apoptosis and natural abundance of the compound, grifolin holds the promise of being an interesting antitumor agent that deserves further laboratory and in vivo exploration.

A pyradine-derivative from the mushroom Albatrellus confluens

A novel pyradine-derivative was isolated from the mushroom Albatrellus confluens. This compound promoted melanin synthesis by B16 melanoma cells.