Fig. 3

The effect of CBP depletion on the phosphorylation of ATM under DNA damage. a Immunoblotting analysis of p-ATM, ATM, p-Chk2, Chk2, acetyl-p53, p-p53, p53, and p21. Levels of the indicated proteins were detected in whole-cell extracts from MCF7 and T47D cells transfected with the indicated siRNAs followed by Doxorubicin (DOX) treatment. b–e Quantification of band intensities for indicated proteins normalized to β-actin. Values were normalized to the corresponding untreated siCtrl condition. f Upper panel: Representative images showing the formation of DOX-induced p-ATM foci (red) and merged with DAPI (blue) staining of nuclei in MCF7 and T47D cells transfected with negative control (siCtrl) or CBP siRNA. Scale bar, 100 µm. Lower panel: The average number of p-ATM nuclear foci per cells from 100 cells. Data are represented as mean ± SEM, n = 3. P < 0.05 is considered significant, Mann–Whitney U test. g Representative images of CBP and p-ATM immunohistochemical staining in breast tissue samples. Immunostaining scores in tumor tissues are shown. Scale bar, 100 µm. h Correlation analysis between CBP and ATM expression in 245 clinical breast cancer samples. Pearson’s correlation coefficient “r” with the corresponding P value is shown