Fig. 1.

Arsenic trioxide, in combination with ascorbate/menadione, enhances breast cancer cell cytotoxicity. a, b MCF-7 (from ATCC) and Resox were incubated 24 h with 5 or 10 μM arsenic trioxide (ATO) with and without Ascorbate 0.5 mM/Menadione 5 μM (Asc/Men). Cytotoxicity was evaluated by using MTT assay (n = 3). c, d MCF-7 (from ECACC) and CAT3 cells were incubated 24 h with 5 or 10 μM arsenic trioxide (ATO) with and without Asc/Men (0.4 mM/4 μM), cytotoxicity was evaluated by using MTT assay (n = 3). Data are mean ± s.e.m. Groups were compared using one-way ANOVA followed by Tukey post hoc test for (a–d). *p value < 0.05; **p value < 0.01; ***p value < 0.001 versus ATO. ^#p value < 0.05; ^###p value < 0.001 versus Asc/Men