Figure 1.

The ATR inhibitor, VX-970, preferentially sensitizes TNBC cells to RT. Clonogenic assays were used to assess the surviving fraction of TNBC cell lines MDA-MB-231 (A), BT-549 (B), and HCC1806 (C), and the normal breast epithelial cell line, MCF10A (D), following RT or RT plus VX-970 (80 nM). For clonogenic assays, cells were trypsinized, plated, allowed to adhere for 4 hours, and treated with vehicle or VX-970 1 hour prior to exposure to varying doses of RT. After 16 hours cells were washed and cultured for 14 days, after which the surviving fraction was assessed. Data are presented as the mean ± SEM from three independent experiments.