Figure 2
Determination of the most effective combined treatment sequence in PC-3 cells. PC-3 cells were analyzed by clonogenic assay to determine the most effective combined genistein + radiation treatment sequence. (A) PC-3 cells treated with 15 μmol/L genistein for 24 hr then irradiated with 3 Gy photons and plated in clonogenic assay. (B) PC-3 cells treated with 15 μmol/L genistein for 24 hr then irradiated with 3 Gy photons, followed by plating and continued treatment with 15 μmol/L genistein throughout clonogenic assay. (C) PC-3 cells irradiated with 3 Gy photons and 24 hr later treated with 15 μmol/L genistein for 24 hr then plated in clonogenic assay. (D) PC-3 cells irradiated with 3 Gy photons, and after 24 hr treated with 15 μmol/L genistein for 24 hr followed by plating and continued treatment with 15 μmol/L genistein throughout clonogenic assay. The colonies were stained and counted after 10 days incubation at 37°C in a 5% CO2/5% O2/90% N2 incubator. Data are presented as the mean survival fraction (± S.E.M.) of triplicate wells as normalized to control cells based on plating efficiency. (*): value statistically significant from control at p < 0.05.