Effect of Flammulina velutipes polysaccharides on endoplasmic reticulum stress‐mediated apoptosis by activating PLC–IP3 pathway in HepG2 cells

• Published in: Journal of food science 2023-01, Vol.88 (1), p.523-536
• Main Authors: Ding, Miao, Lv, Kai, Zhang, Dongliang, Fan, Wentao, Tsopmejio, Ivan Stève Nguepi, Jin, Zhouyu, Song, Hui
• Format: Article
• Language: English
• Subjects: Antineoplastic drugs; Antitumor agents; Apoptosis; Calcium (intracellular); Calcium ions; Chemotherapy; Endoplasmic reticulum; Endoplasmic Reticulum Stress; Flammulina; Flammulina velutipes; Flammulina velutipes polysaccharides; Flow cytometry; Galactose; Gene expression; Gluconic acid; Hep G2 Cells; HepG2 cells; Humans; Immunofluorescence; Inositol 1,4,5-trisphosphate receptors; Inositols; Intracellular; Mannose; Molecular weight; Phenylbutyric acid; Phospholipase; Phospholipase C; Polysaccharides; Polysaccharides - pharmacology; Pretreatment; Saccharides; Type C Phospholipases
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/1750-3841.16423

Flammulina velutipes polysaccharides (FVP) have been proven to induce apoptosis in HepG2 cells. It is well known that endoplasmic reticulum stress (ERS) is involved in apoptosis. However, ERS mediates FVP‐induced apoptosis in HepG2 cells remains unclear. In our study, the results indicated that FVP caused ERS in HepG2 cells. They showed that FVP were water‐soluble polysaccharides with the weight average molecular weight of 1972 kDa, which were mainly composed of mannose, gluconic acid, glucose, galactose, xylose and fructose in a molar ratio of 6.6 : 1.3 : 79.9 : 7.4 : 3.4 : 1.5. After FVP treatment, the expression levels of genes and proteins related to ERS were upregulated. The inhibition of ERS by 4‐phenylbutyric acid (4‐PBA) pretreatment could significantly reduce the role of FVP in inducing apoptosis. We further found the results of immunofluorescence and flow cytometry showing that Ca2+ in the ERS leaked out, and the intracellular Ca2+ concentration increased after FVP treatment. The pretreatment with the phospholipase C (PLC) inhibitor U73122 proved that FVP caused excessive intracellular Ca2+ concentration by activating the phospholipase C–inositol‐1,4,5‐triphosphate (PLC‐IP3) pathway, resulting in ERS, and ultimately leading to apoptosis. In summary, our results indicated that FVP induced ERS‐mediated apoptosis by activating PLC–IP3 pathway in HepG2 cells. Practical Application This work may suggest that FVP could be used as an adjuvant therapy to anticancer drugs, providing new application prospects and possibilities.