Figure 3.

EB-3D sensitizes breast cancer cells to common treatment. (A–C) MTT cell viability assay in breast cancer cell lines treated with EB-3D in combination with doxorubicin (Doxo) (A), 5-fluorouracil (5-FU) (B), and cisplatin (Cis-Pt) (C) for 72 h. The percentages of cell viability were normalized to untreated cells. Symbols and bars represent the mean ± SEM of at least four independent experiments. (D–F) Combination index (CI) calculated at the ED₅₀ and ED₇₅ for Doxo (D), 5-FU (E), and Cis-Pt (F) combination, where synergism is defined by CI < 1. (G) Flow cytometry analysis of cell death. Breast cancer cells were treated with 1 μM of EB-3D or Cis-Pt (20 μM for MDA-MB-231 and MCF-7 or 2.5 μM for MDA-MB-468) or with the simultaneous addition of EB-3D and Cis-Pt for 72 h. Alternatively cells were pretreated with EB-3D for 72 h and then, after EB-3D removal, treated with Cis-Pt for a further 72 h. Bars represent the mean ± SEM of at least four independent experiments. Statistical significance was determined using ANOVA with Newman–Keuls correction. Asterisks indicate a significant difference between indicated groups. * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001.