Survival curves for non-stem and CSC-like MDA-MB-453 and MDA-MB-231 cells after irradiation.

(A) Colonies were obtained with non-stem and stem-like MDA-MB-453 cells. Cells were unirradiated (0 Gy) or irradiated (6.25 Gy), trypsinized, counted and plated. Cells were grown for 1–3 weeks and stained with crystal violet. (B, C) Survival curves for non-stem and stem-like MDA-MB-453 (B) and MDA-MB-231 (C) cells were determined after irradiation. Cells were exposed to various doses (1.25 Gy-8.75 Gy) of γ-radiation. Cells were trypsinized, counted and plated. Colony formation was determined 1–3 weeks after irradiation. Error bars represent standard error from the mean for three separate experiments.