Withaferin A (WA) treatment causes reactive oxygen species (ROS) production in human breast cancer cells.

<p>(A) Chemical structure of WA. (B) Flow cytometric analysis for MitoSOX Red fluorescence in DMSO-treated control and WA-treated MDA-MB-231 and MCF-7 cells (4 h treatment). Results are shown as enrichment factor relative to DMSO-treated control (mean ± SD, <i>n</i> = 3). <i>*P</i><0.05, significantly different compared with DMSO-treated control by one-way ANOVA with Dunnett's adjustment. (C) Fluorescence microscopy for MitoSOX Red fluorescence in MDA-MB-231 and MCF-7 cells following 4 h treatment with DMSO or 2.5 µM WA. (D) Fluorescence microscopy for MitoSOX Red fluorescence in HMEC following 4 h treatment with DMSO or 2.5 µM WA. (E) Representative EPR spectra in HMEC treated for 4 h with DMSO or 5 µM WA. All experiments were repeated at least twice.