Non-starch polysaccharides from different developmental stages of Pleurotus tuber-regium inhibited the growth of human acute promyelocytic leukemia HL-60 cells by cell-cycle arrest and/or apoptotic induction

摘要

The chemical compositions and in vitro anti-proliferative activities of the water-soluble non-starch polysaccharides (NSPs) extracted from the fruiting body,mycelium and culture medium (coded as HWE,EDP and CEP,respectively) of a novel edible mushroom Pleurotus tuber-regium (PTR) were compared.HWE is likely to be a heteropolysaccharide-protein complex with a high molecular weight of 186 x 10~4.Glucose-rich EDP had a moderate MW of 50.9 x 10~4 while mannose-rich CEP had a low MW of 4.4 x 10~4.Among all PTR NSPs,HWE had the strongest cytotoxicity (approximate IC50: 25 mu g/ml) and exerted effective anti-proliferative activity at 200 mu g/ml against human acute promyelocytic leukemia cells (HL-60).All PTR NSPs induced apoptosis in HL-60 cells with an increase in the ratio of Bax/Bcl-2.Analysis from flow cytometry and Western blot demonstrated that EDP caused G2/M arrest in HL-60 cells by lowering the Cdk1 expression while HWE caused S arrest in the HL-60 cells by a depletion of Cdk2 and an increase in cyclin E expression.