(a) Imaging DNA in prostate cell nuclei with DAPI to quantify chromatin condensation. The upper row is raw fluorescence images and the second row shows inverted images to enhance visualization. PC3 and CL2 are highly metastatic, DU145 is moderately metastatic, LNCaP is non-metastatic, and RWPE-1 is a normal cell. Scale bar is 20 μm. (b) Average nuclear fluorescence intensity, taken from the raw images, for different prostate cell lines (n = 40, p < 0.05 for all comparisons except PC3-CL2 and RWPE-1-DU145, two-sample Kolmogorov-Smirnov test from 3 independent samples).