Effect of VE-821 (ATR inhibitor) and KU-60019 (ATM inhibitor) on three-dimensional (3D) Madin-Darby canine kidney (MDCK) cyst growth and cell viability (MTT assay) in human kidney tubular cell lines. (A) Representative images of MDCK cysts treated with forskolin alone, VE-821 (2, 5, and 10 µM) or KU-60019 (2, 5, and 10 µM) on Days 6 (upper panel) and 12 (lower panel) (Images were obtained using 10x objective). (B) and (C) Mean cyst diameter of MDCK cysts on Days 6 and 12, treated with either VE-821 or KU-60019 as determined by image analysis; (D) and (E) Mean number of viable cells (as a percentage of vehicle, measured by the MTT assay) in HK-2, WT 9-7, and WT 9-12 cells treated with either VE-821 (2, 5, and 10 µM, (D)) or KU-6001 (2, 5, and 10 µM, (E)) for 24 h. * p < 0.05 compared to forskolin alone, # p < 0.05 compared to 2 µM by one-way ANOVA, followed by post hoc analysis with the Tukey–Kramer HSD test. Data presented as means ± SD (n = 3 per group).