Fig. 6.

In models with ATM loss of functionality, ATR phosphorylates RAD50; pRAD50 levels are supressed by the ATR inhibitor AZD6738. a Expression of pRAD50(Ser635) by IHC in an ATM KO FaDu xenograft model treated with AZD6738 (50 mg/kg oral) or the vehicle control. Representative images are shown for 8 h post AZD6738 dose and 3 h post the vehicle. b HALO image analysis was used to generate a pRAD50 H-score per sample. Mean ± SD given. Each data point indicates an individual mouse. * indicates p ≤ 0.05, ***p ≤ 0.001 by One-way ANOVA, followed by Tukey’s multiple comparison correction. c Expression by IHC of pRAD50(Ser635) and γH2AX in NCI-H23 cells, ATM functionally deficient, 24 h post-treatment with a DMSO control or 1 µM aphidicolin alone or in combination with 1 µM AZD6738. d Immunoblot of pATR(Thr1989), pCHK1(Ser345), pRAD50(Ser635) and γH2AX in NCI-H23 cells, 24 h after treatment with DMSO, aphidicolin (1 µM) and AZD6738 (0.3 or 1 µM) monotherapy or in combination. Expression of total proteins also shown for each biomarker normalised to a Vinculin loading control. Scale bars: 50 µm