Fig. 3
The effect of PARP-1 inhibition in combination with external beam X-radiation. SK-N-BE(2c) (a, b, c) and UVW/NAT cells (d, e, f) were treated simultaneously with rucaparib (a, d) or olaparib (d, e) in combination with a range of doses of external beam X-radiation. Cells were treated with rucaparib or olaparib, at concentrations of 1 μM, 10 μM or 30 μM, following exposure to a range of doses of X-radiation, for 24 h prior to seeding cells for clonogenic assay. The X-irradiation dose associated with 50 % cell kill (IC50) and the dose enhancement factors corresponding to 50 % clonogenic cell kill (DEF50) are presented for SK-N-BE(2c) (c) and UVW/NAT (f) cells. Data are means ± SEM, n = 3; **p < 0.01, *** p < 0.001 compared to the IC50 in the absence of drug