Analysis of PARPi-induced DDR in cell lines shows higher induction of multiple readouts in BRCA2-/- cells compared to BRCA1+/- and BRCA1+/+ cells. (A) 48 or 72 hr (columns) PARPi AZD2281 (AZD, 6 μg/mL)-induced Log2Fold values for DDR readouts p-RPA2, p-DNA-PKcs, p21, p-ATM, and p-BRCA1 (rows) are shown for CyclinA2- or CyclinA2+ subsets (columns) of tested cell lines. Values shown are mean averages from 2 independent experiments. Cell lines are coded by HRR status (BRCA1+/+, squares; BRCA1+/-, circles; BRCA2-/-, crosses). (B) Flow plot examples of p-RPA2, p-DNA-PKcs, p-ATM induction in BRCA1+/+, BRCA1+/-, and BRCA2-/- cell lines at 48 h (Red: Unstimulated, Blue: AZD2281).