Variable effects of TH287 and TH588 MTH1 inhibitors on DNA oxidation and apoptosis. a - d Fpg-modified alkaline comet assay. DMSO (0.066% v/v) used as a vehicle control. Means ± SD calculated from 3 independent experiments. 200 randomly selected individual comets were scored for each sample per experiment. Mean values calculated from 3 independent experiments were used to generate final mean values and SD. Error bars represent SD. e - h Annexin V-FITC/PI apoptosis assay to determine cell viability. DMSO (0.5–1.5% v/v) or VP-16 (+ve) were applied as vehicle controls and positive controls, respectively. 3 independent experiments performed (except 150 μM VP-16). Percentage values from each experiment were used to calculate final mean values and SD. Error bars represent SD. Asterisks indicate a significant difference between treated and untreated percentage values (****P < 0.0001, **P < 0.01, *P < 0.05).