Fig. 6

Cell proliferation after irradiation measured by BrdU, summarized for all BC cell lines at 21% (a) and 5% (b) oxygen concentration (black column = control; gray column = 3 mM 3-OHB). No significant influence of 3-OHB was seen. Columns represent mean ± SEM of three independent experiments with six replicate wells per experiment. Two representative dose-response curves for MCF7 and MDA-MB 468 are shown (c–f). MDA-MB 468 cells were sensitive to radiation (c, d), while MCF7 cells were relatively insensitive even to high doses (e, f). Open and filled symbols represent mean (± SD) of S-phase cell counts in 3-OHB-untreated control and 3-OHB-treated cells, respectively. The data were normalized to the corresponding values of non-irradiated cells at 21 or 5% oxygen, respectively