Ganoderma lucidum polysaccharide inhibits the proliferation of leukemic cells through apoptosis

Objective: To investigate the cytotoxic effect of polysaccharides derived from Ganoderma lucidum on T lymphocyte leukemia cells. Methods: Water-soluble polysaccharides were extracted from the fruit bodies of G. lucidum, purified, and characterized using HPGPC-MALLS and NMR. The cytotoxicity of G. lucidum polysaccharide fraction 5 (GLP5) to T lymphocyte leukemia cell line Jurkat and human immortalized epidermal cell line HaCat was assessed using MTT assay. Apoptosis was assessed using flow cytometry. Expressions of apoptosis-related genes in the cells after being exposed to GLP5 were detected using Western blot assay.Results: GLP5 was a β-(1→3) and β-(1→6) linked glucan. It inhibited the proliferation of Jurkat cells in a concentration-dependent manner and the half-maximal inhibitory concentration (IC50) was 34.5 mg/L but did not suppress the growth of HaCat cells. Apoptotic cells in Jurkat cells were detected to increase with increasing GLP5 concentrations. The expression levels of cleaved caspase-3 were significantly higher after the cells were exposed to 25 and 50 mg/L GLP5 when compared to non-exposed cells (Control). In addition, the expression levels of BAX and Bcl2 were significantly up- and down-regulated after treatment with GLP5 at 25 and 50 mg/L when compared with control (P<0.05), respectively.Conclusions: GLP5 has antiproliferative activity against Jurkat cells and the activity is likely mediated through the activation of apoptosis pathways.