Pleurotus pulmonarius polysaccharides inhibit glioma growth through the Hippo signaling pathway and regulate the structure of gut microbiota

Pleurotus pulmonarius (Fr.) is an edible and medicinal fungus. Here, we isolated polysaccharides from P. pulmonarius and evaluated their physicochemical properties, anti-tumor activity, and gut microbiota regulation. Freeze-dried powder of P. pulmonarius fruiting body polysaccharide (PFP) is a heteropolysaccharide, mainly composed of galactose (295.52 μg/mg). PFP significantly inhibited glioma cell survival in vitro and U251 glioma cell tumor growth in nude mice (inhibition rate, 53.70%). PFP inhibited YAP1 and TAZ protein expression levels, upregulated those of MST1 and LAST1, regulated Hippo signaling, stimulated E-cadherin, and downregulated N-cadherin proteins, inhibiting tumor migration. PFP downregulated Bcl-2 protein expression, upregulated that of Cleaved Caspase 3, and induced tumor cell apoptosis. PFP regulated gut microbiota structure in tumor-bearing nude mice and increased the relative abundance of beneficial bacteria. In summary, PFP is a natural, safe, and non-toxic anti-cancer drug, and a potential probiotic. Our data provide theoretical guidance for the treatment of glioma.