Fig. 4: Impact of ATR, CHK1 and WEE1 inhibitors on cell cycle arrest and HRR induction by rucaparib.

a Cell cycle analysis of human ovarian cancer IGROV-1 and UWB paired cells following 24 h exposure to rucaparib single agent and in combination with VE-821 (1 µM), PF-477736 (50 nM) and MK-1775 (100 nM). 10 µM EdU was added to cells during the final hour of drug exposure. Data are mean and standard error of 3 independent experiments in IGROV-1 cells and mean of 2 independent experiments in UWB paired cells. Histograms and densitometry plots of representative experiments are shown in supplementary figure 3A, B. b, c Formation of γH2AX foci was measured to indicate the induction of RS/DNA damage and RAD51 foci formation as an indicator of HRR function. Images are representative of observed differences between HRP and HRD cells upon exposure to DMSO, 10 µM rucaparib, 10 µM rucaparib + 1 µM VE-821, 10 µM rucaparib + 50 nM PF-477736 or 10 µM rucaparib + 100 nM MK-1775. d Data show mean γH2AX foci/cell and mean RAD51 foci/γH2AX positive cell, with the exception of HRD UWB cells where RAD51 was analysed in all cells due to lack of induction of γH2AX with rucaparib. A total of 3 independent experiments are shown and standard error in cells treated with 10 µM rucaparib single agent and with the addition of 1 µM VE-821, 50 nM PF-477736 or 100 nM MK-1775 for 24 h prior to fixation.