Figure 3.

Protein expression and nuclear foci formation in breast cancer cell lines. (a) Cellular protein levels. 53BP1 and Vimentin band intensities were normalized to loading controls. Values for T47D cell extracts, loaded as a reference on each blot, were set to 1. Mean relative Western blot signals per cell line were calculated from two independent experiments. Box plots in the upper panels show mean values (cross), the median (line), and 95% CI (whiskers) for untreated and for 7d Eribulin-treated non-TNBC (N=4) and TNBC cell lines (N=7). The Kruskal–Wallis test did not reveal significant differences in the case of 53BP1. Representative immunoblots are shown in the bottom panels. Vimentin staining was detected in all TNBC but was negative in all non-TNBC cell lines in which BT20 served as a reference. Actin normalized protein levels are indicated above the 53BP1 and Vimentin signals. (b) Focal accumulation of 53BP1 in the nucleus of MBC cell lines. 53BP1 foci were detected by immunofluorescence microscopy in MBC cell lines. The graph presents quantitative data in box plots as in A; ~300–900 nuclei per sample were scored in two independent experiments each, and mean values were calculated for each cell line. *P<0.05, Kruskal–Wallis test, Mann–Whitney U test. Representative immunofluorescence images are displayed in Supplementary Figure S3.