Figure 2. CHK1 and PARP1 inhibitors interact to cause DNA damage. (A) BT474, (B) 4T1 cells were treated with AZD2281 (1 μM), AZD7762 (25 nM) or the drug combination for the indicated times. Cells were isolated and subjected to alkaline comet assay. The length of the tail being scored 1–5 (n = 3 ± SEM) * p < 0.05 value greater than corresponding vehicle control.