Figure 1
The differential impact of ADR on GSH/GSSG ratio, the influx of cystine and the expression of SLC7A11 in MCF-7S and MCF-7R cells. (A) The baseline ROS level in MCF-7R cells was remarkably higher than in MCF-7S cells. (B) ADR reduced the intracellular GSH/GSSG ratio in MCF-7S cells to a comparable level to that of MCF-7R cells, which was reversed by NAC (10 mM, 30 min of pretreatment). (C) The utilization of cystine was much higher in the culture medium of MCF-7S cells than that of MCF-7R cells, although both groups were treated with the same initial concentration (1.0 mM). (D) ADR inhibited the influx of cystine and the efflux of glutamic acid (substrates of SLC7A11) in MCF-7S (1 μM) and MCF-7R (5 μM) cells. (E) The SLC7A11 mRNA level in MCF-7R cells was intrinsically lower than in MCF-7S cells. Moreover, ADR markedly inhibited SLC7A11 mRNA expression in MCF-7S cells (1 μM), but showed a marginal effect on MCF-7R cells (5 μM). (F) ADR down-regulated SLC7A11 protein expression in MCF-7S cells. (G) The inhibitiory effect of ADR on SLC7A11 mRNA expression showed time-dependence and concentration-dependence in MCF-7R cells. All of the experiments were conducted in triplicate, and data with error bars are presented as the mean ± SD (n = 3). *p < 0.05; **p < 0.01 vs. control.
