Figure 4.

Loss of 53BP1 lowers the response of MDA-MB-436 xenografts to PARP inhibitors in nude mice. Simmiparib or olaparib were orally administered to nude mice bearing xenografts derived from MDA-MB-436 cells (WT) or the ^#26 clonal variant (53BP1^−/−), for 21 d. (A and B) Changes in the relative tumor volume (RTV) (A) and the animal body weight (B) over the treatment time; n=6 for the treatment groups and 12 for the control groups. (C) Protein levels in the indicated treated xenografts, measured by Western blotting. In each group, three xenografts were detected (because some xenografts were very small so that not enough materials could be obtained for the detection, particularly in the WT treatment group). Representative images are shown. ^*P<0.05, ^**P<0.01 vs WT.