Fig. 4

γH2AX (S139) staining and DNA damage response protein expression. Fluorescent images of γ-H2AX staining for (A) MCF7, (B) MCF7-miR526b, (C) MCF7-miR655 and (D) MCF7-COX2 cells following DOX treatment and rest. Images taken at 40X magnification, and the scale bar is 100 μm. Red, γ-H2AX; blue, DAPI. (E) Quantification of γ-H2AX staining. Data shown as mean +/- SD (n = 3 bioreplicates, MCF7: DMSO vs. DOX **p = 0.0046; MCF7-miR526b: DMSO vs. DOX **p = 0.0014, DOX vs. DOX + Rest *p = 0.0316; MCF7-miR655: DMSO vs. DOX ***p = 0.0005, DOX vs. DOX + Rest *p = 0.0325; MCF7-COX2: DMSO vs. DOX ****p < 0.0001, DOX vs. DOX + Rest ****p < 0.0001; DOX: MCF7 vs. MCF7-COX2 *p = 0.0339, MCF7-miR526b vs. MCF7-COX2 *p = 0.0209, two-way ANOVA with Tukey’s post-hoc). (F) Western blot images of ATM, Chk2 and p-Chk2 following DOX treatment and rest. For full blot images, see Supplementary Fig. S7-S9. Quantification of western blot analysis for (G) ATM (n = 2 bioreplicates), (H) Chk2 and (I) p-Chk2. Data in (H) and (I) shown as mean +/- SD (For Chk2, n = 4 bioreplicates, MCF7-miR655: DMSO vs. DOX ***p = 0.0007, DMSO vs. DOX + Rest ***p = 0.0004, one-way ANOVA with Tukey’s post-hoc. For p-CHK2, n = 3 for MCF7, MCF7-miR526b and MCF7-miR655 and n = 4 for MCF7-COX2). Non-significant comparisons not labelled.