Fig. 4

Increased cell viability of Caco-2 (a) and Ishikawa (b) upon pre-incubation with NAC (10 mM) prior to drug treatments. The columns represent the fold changes in cell viability normalised against NAC-free treatment. Data are mean ± SEM (N = 3 separate experiments); p values comparing NAC-free and NAC-pre-incubated cells were calculated using one-way ANOVA with Tukey multiple comparison post-hoc analysis; ns, not significant, *p < 0.05, **p < 0.01, ***p < 0.001 and ****p < 0.0001. c Comparison of the changes in cell viability between the Caco-2 and Ishikawa cells upon pre-incubation with NAC. Data are mean ± SEM (N = 3 separate experiments); p values comparing Caco-2 and Ishikawa were calculated using two-tailed t-test; *p < 0.05 and **p < 0.01