Xylopine Induces Oxidative Stress and Causes G₂/M Phase Arrest, Triggering Caspase-Mediated Apoptosis by p53-Independent Pathway in HCT116 Cells

Figure 10

Effect of the antioxidant N-acetyl-L-cysteine (NAC) in xylopine-induced apoptosis in HCT116 cells determined by flow cytometry using annexin V-FITC/PI staining. (a) Representative flow cytometric dot plots showing the percentage of cells in viable, early apoptotic, late apoptotic, and necrotic stages. (b) Quantification of apoptotic cells. The cells were pretreated for 1 h with 5 mM NAC and then incubated with 14 μM xylopine (XYL) for 48 h. The negative control (CTL) was treated with the vehicle (0.1% DMSO) used for diluting the compound tested. Doxorubicin (DOX, 1 μM) and oxaliplatin (OXA, 2.5 μM) were used as positive controls. Data are presented as the mean ± S.E.M. of three independent experiments performed in duplicate. Ten thousand events were evaluated per experiment, and cellular debris was omitted from the analysis. compared with the negative control by ANOVA followed by Student–Newman–Keuls test. compared with the respective treatment without inhibitor by ANOVA followed by Student–Newman–Keuls test.

(a)

(b)