-ceramide increased chromatin condensation levels of H1299 lung cancer cells. (a) Flow cytometry-based DAPI profiles for C2-ceramide-treated cells. Cells treated with different concentrations (0 to 50 μM) of C2-ceramide for 24 h. Positive % is indicated in each panel; (b) Quantificative analysis of DAPI-positive population. Data are presented as mean ± S.D. (n = 3). Asterisks indicate statistically significant differences compared to control (P < 0.001).