Ginseng polysaccharide (GPS), a polymer of glucose and the primary constituent extracted from panax ginseng, has been documented to exert various pharmacological properties, including anti-tumor properties. To provide further insights into the anti-tumor functions of GPS, the present study was designed to investigate the effect of GPS on apoptosis and the cell cycle of human leukemia cell line K562 cells, and its underlying mechanisms. The results demonstrated that GPS could inhibit K562 cell proliferation and induce apoptosis in vitro in a concentration- and time-dependent manner. The transcription of P38 and c-Jun NH2-terminal kinase (JNK) mRNA were significantly augmented, while the transcription of extracellular signal-regulated kinase (ERK) mRNA were significantly reduced following treatment with GPS compared with the control group (all P<0.05). In addition, GPS treatment markedly suppressed the expression of phosphorylated (p)-ERK, nuclear factor (NF)-κB p65 and cyclin D1, and increased the synthesis of p-P38 and p-JNK protein expression, as evidenced by immunofluorescence and western blotting analyses. In conclusion, the results indicate that the GPS-mediated MAPK/NF-κB/cyclin D1 signaling pathway serves a crucial role in cell cycle arrest and apoptosis of K562 cells.
Keywords: K562; apoptosis; cell cycle; cyclin D1; ginseng polysaccharide; mitogen-activated protein kinase; nuclear factor-κB.