Figure 2.

Radiation-induced G2 arrest. (A–C) Fraction of mitotic cells. Exponentially growing cells were treated for 2 h with the inhibitors as indicated (olaparib: 1 µM; adavosertib: 240 nM; adavosertib + prexasertib: 60 nm + 1 nM, respectively), before irradiation with 0 or 6 Gy. Five or eight hours after irradiation cells were fixed and stained for phospho-histone H3 (P-H3+) to assess the number of mitotic cells. (A) Gating. (B) Quantification of the mitotic fraction at 5 h after irradiation. (C) Quantification at 8 h after irradiation. (D) Long term G2 arrest. Cells were treated and irradiated as in (A–C). Twenty-four hours after irradiation the cells were fixed, and the cell cycle distribution was assessed by DAPI staining and flow cytometry.