Figure 2.

PARP1 inhibitor ABT-888 (veliparib) alters IRIF dynamics and suppresses cell proliferation. A, ABT-888 increased the number of residual IRIF 24 h after IR. Cells were pretreated with DMSO (control) or 10 μM ABT-888 (inset) for 30 min before IR. Live cell images shown at 3 h and 24 h. Scale bar, 5 μm. B, Immunofluorescence reveals co-localization of GFP-IBD with γH2AX, MDC1, and endogenous, full-length 53BP1 at IRIF in cells treated with 6 Gy ± ABT-888. Nuclei indicated by DAPI staining (blue). Scale bar, 10 μm. C, Time-lapse live cell imaging of GFP-IBD localization in MCF7^Tet-On GFP-IBD cells treated with 6 Gy ± ABT-888. Scale bar, 10 μm. D, ABT-888 suppresses cell growth of irradiated MCF7^Tet-On GFP-IBD cells. Cells were treated as shown, fixed at 10 d and stained with crystal violet.