A polysaccharide from Grifola frondosa fruit body induces HT-29 cells apoptosis by PI3K/AKT-MAPKs and NF-κB-pathway

Background: A neutral polysaccharide was isolated from the fruiting body of a mushroom Grifola frondosa (GFP-A). The tumor suppressive activity of GFP-A on protein expressions of PI3K/AKT, MAPKs, nuclear factor kappa B and caspase pathways in HT-29 cells were investigated. Methods: The inhibitory effect and mechanism of GFP-A on the HT-29 cells were investigated. The cell viability was examined by MTT. Scanning electron microscopy analysis and flow cytometry were conducted to examine the apoptosis of cells. The protein expressions of PI3K/AKT, MAPKs, nuclear factor kappa B and caspase pathways were analyzed using western blot. Results: The results of MTT assay showed that GFP-A of 180 mu g/mL could significantly inhibit the proliferation of HT-29 cells. Western blotting results showed that GFP-A decreased the protein expression of PI3K and AKT, enhanced the phosphorylation of c-Jun N-terminal kinase (JNK), p38 MAPK and inhibited the phosphorylation of ERK1/2 and the translocation of nuclear factor-kappa B (NF-kappa B) into the nucleus. In the meanwhile, GFP-A could up-regulate the ratio of Bax to Bcl-2, increase the release of cytochrome C to cytoplasm, ultimately lead to the activation of caspase-9. Conclusions: The above results confirmed that GFP-A promoted the apoptosis of HT-29 cells through PI3K/AKT-MAPKs-NF-kappa B and caspase signaling pathways. (C) 2020 Elsevier B.V. All rights reserved.