Fig. 5

ROS production mediates cytotoxicity of LNCs. Data for MDA-MB-231 are shown on the left side of the figure and data for MDA-MB-468 are shown on the right side of the figure. a, b Cells were incubated for up to 4 h 37 °C with the indicated concentrations of LNCs in the absence or presence of the antioxidant NAC, and ROS production was measured using the fluorescence probe CM-H₂DCFDA. Bars represent mean values ± SEM from three independent experiments. *p < 0.05; **p < 0.01; ***p < 0.001 for comparison with data obtained in the absence of LNCs and ^#p < 0.05; ^##p < 0.01; ^###p < 0.001 for comparison with cells preincubated with NAC. c, d Effect on ROS production after incubation of the cells at 37 °C with 100 µM H₂O₂ as a positive control. Bars represent mean values ± SEM from four independent experiments. *p < 0.05; **p < 0.01; ***p < 0.001 for comparison with data obtained in the absence of H₂O₂ and ^#p < 0.05; ^##p < 0.01; ^###p < 0.001 for comparison with cells preincubated with NAC. e, f Changes of lipid peroxidation in MDA-MB-231 and MDA-MB-468 cells following treatment of cells for 2 h at 37 °C with LNCs (0.5 and 1.0 mg/ml). Lipid peroxidation was estimated by flow cytometry after staining of cells with BODIPY-C11 for 30 min. Bars represent mean values ± SEM from four independent experiments; *p < 0.05; **p < 0.01; ***p < 0.001 for comparison with data obtained in the absence of LNCs and ^#p < 0.05; ^##p < 0.01; ^###p < 0.001 for comparison with cells preincubated with NAC. g, h Cell viability of MDA-MB-231 and MDA-MB-468 measured using the CellTiter-Glo^® assay (ATP measurements) after 24 h treatment of cells with varying concentrations of LNCs in the absence or presence of the free radical scavengers NAC (5 mM) and GSH (10 mM). The graphs show mean values ± SEM from at least three independent experiments; *p < 0.05; **p < 0.01; ***p < 0.001 for comparison of cells preincubated with NAC. ^##p < 0.01; ^###p < 0.001 for comparison of cells preincubated with GSH (10 mM)