Dose-dependent response to CUR.

<p>A- Cellular DNA content in attached MCF7 (black bars) and MDA-MB-231 (white bars) breast cancer cells exposed to increasing concentrations (0.5, 2.5, 10, 25, and 50 mg.l⁻¹) of CUR for 24 h, measured using the Hoechst fluorescence intensity assay. *, P<0.05, **, P<0.01, CUR <i>vs.</i> CTL, Mann-Whitney test. B- DNA fragmentation expressed in tail DNA in MCF7 tumor cells exposed to increasing concentrations (0.5, 2.5, 10, 25, and 50 mg.l⁻¹) of CUR for 24 h, measured using the alkaline Comet assay. *, P<0.05, CUR <i>vs.</i> CTL, Mann-Whitney test. C- Total glutathione <i>S-</i>transferase (GST) activity in MCF7 tumor cells exposed to increasing concentrations (0.5, 2.5, 10, 25, and 50 mg.l⁻¹) of CUR for 24 h, measured using the Cayman Chemical Company assay kit. **, P<0.01, CUR <i>vs.</i> CTL, Mann-Whitney test. D- Set of typical 1D HRMAS ¹H-NMR spectra of MCF7 breast cancer cells in the 0.5–4.5 ppm spectral range. From bottom to top, cells exposed to 0, 0.5, 2.5, 10, 25, and 50 mg.l⁻¹ CUR. Thin arrows, signals from glutathione (GSx) at positions 2.25, 2.55, 2.98, and 3.78 ppm. Grey arrowheads, signal from total free fatty acids (tFA) at positions 1.30 and 0.89 ppm. E- Set of typical 1D HRMAS ¹H-NMR spectra of MDA-MB-231 breast cancer cells. From bottom to top, cells exposed to 0, 10, and 50 mg.l⁻¹ CUR. Arrows, as in Fig. 1D. F- Two-dimensional HRMAS ¹H-NMR spectra of intact MCF7 tumor cells, here from the 25 mg.l⁻¹ CUR group. Thin arrows, cross-peaks of glutathione (GSx) at positions 2.25×2.55, 2.25×3.78, 2.55×3.78, and 2.98×4.55 ppm×ppm. Square, area containing gluconate (Gna) signals. G- Square area magnified from the spectrum in Fig. 1F. Arrowheads, cross-peaks from Gna at positions 4.13×4.02, 4.02×3.76, and 3.76×3.66 ppm×ppm. Gna was quantified from the first 2 cross-peaks.