Effect of CpG-ODN and/or 5-FU treatment on apoptosis of HepG2 cells. A: The apoptosis was examined using annexin V-FITC/PI staining and flow cytometry analysis. One representative flow cytrometry analysis of apoptosis in HepG2 cells. Fluorescence intensity for annexin V/FITC is plotted on the x-axis, and PI is plotted on the y-axis. FITC-/PI-, FITC+/PI-, FITC+/PI+, FITC-/PI+ was regarded as living, early apoptotic, late apoptotic and necrotic cells, respectively. B: The percentage of apoptotic cells examined by annexin V-FITC/PI staining and flow cytometry analysis. Results are presented as mean ±SD of three separate experiments. ***P<0.001 versus medium. ###P<0.001 versus 5-FU. In this figure, 5-FU, CpG(2) and CpG(4) represent that the concentration of 5-FU, CpG-ODN and CpG-ODN is 7.5 μg/ml, 2 μM, 4 μM, respectively.