Figure 5. PARP1 and CHK1 inhibitors radiosensitize mammary carcinoma cells. (A) BT474, (B) 4T1 cells were treated with AZD2281 (1 μM) and AZD7762 (25 nM) in combination for 6h. As indicated cells were irradiated (4 Gy) 30 min after drug exposure. Cells were isolated 6h and 12h after exposure, and viability was determined using trypan blue exclusion. (n = 3 ± SEM). * p < 0.05 value greater than corresponding vehicle control.