A polysaccharide from the fungi of Huaier exhibits anti-tumor potential and immunomodulatory effects

A neutral water-soluble polysaccharide (W-NTRP), with a molecular weight of 2.5 × 104 Da, was isolated from the fruit bodies of Trametes robiniophila (Huaier). Gas chromatography (GC) results indicated that W-NTRP was determined to be galactose (Gal), arabinose (Ara) and glucose (Glc), with a relative molar ratio of 4.2:2.5:0.7. Its antitumor and immunomodulatory activity were evaluated in vitro. W-NTRP showed remarkable inhibitory effect on three human cholangiocarcinoma cell lines (QBC939, Sk-ChA-1 and MZ-ChA-1), with respective IC50 values of 47.8, 75.9, and 43.7 μg/mL, but had no cytotoxicity to L-929 normal cells. Furthermore, W-NTRP had proliferation promoting effect on mouse splenocytes with or without concanavalin A (ConA) or lipopolysaccharide (LPS) in a bell-shaped dose-response manner. In addition, W-NTRP could prominently stimulate macrophages to produce nitric oxide (NO) through the up-regulation of inducible NO synthase (iNOS) activity. These results suggest that W-NTRP could be explored as a potential antitumor agent for cholangiocarcinoma.