Fig. 6: ROS production and ER stress are increased by MHYs.

a HT29 cells were treated with NAC (5 mM), MHYs (10 μM), or pyocyanin (200 µM, a positive control) for 1 h and ROS production was measured by FACS analysis. Data are presented as ratios relative to the vehicle control. b HT29 cells were pre-treated with NAC (5 mM) for 30 min followed by MHYs (10 μM) for 24 h and then the expression levels of ER stress marker proteins were evaluated. c HT29 cells were treated with MHYs (10 μM), gefitinib (0.25 nM), or PD168393 (2 μM) for 24 h to measure PERK phosphorylation. d Src phosphorylation levels were measured in HT29 cells pre-treated with NAC (5 mM, 30 min) and then treated with MHYs (10 μM, 24 h). Relative density measurements correspond to the intensities of the immunoblotting bands normalized to an internal control (n = 3). Data are shown as mean ± SD. e HT29 cells were pre-treated with NAC (5 mM) for 30 min followed by MHYs (10 μM) for 24 h and then cell viabilities were measured by MTT assays. Data presented as a percent of control cells. Statistical significance was determined by one-way ANOVA followed by Bonferroni’s (a, b) or Tukey (f) post-hoc test. Statistical significance is indicated as **p < 0.01, ***p < 0.001, ****p < 0.0001. The ns indicates that the comparison was not statistically significant