a, b, 8-Oxoguanosine-induced treatment with MMP-3 (a; scale bar, 50μm) and quantification of increased nuclear staining relative to untreated (b; error bars, 95% confidence intervals). c, Induction of PALA resistance by MMP-3 (blue diamonds, MMP-3; red squares, untreated). d, Fluorescence in situ hybridization of the CAD gene locus (red). e, ROS and oxygen dependence of PALA resistance induced by 14 days of treatment with MMP-3. f, Frequency plots of comparative genomic hybridization analyses of cells grown in the absence (top) or presence (bottom) of MMP-3, and then selected with PALA. Green, amplifications; red, deletions. For all graphs, error bars represent s.e.m.