SETMAR knockdown induce premature senescence in residual cells. (A–D) Line graphs show the growth of parent and RR cells of U87MG and SF268 cells stably transfected with scrambled (Scr), shRNA, or siRNA against SETMAR. Results in the line graph are the composite data from 3 independent experiments. (E, F) Senescence-associated β-galactosidase staining at days 12 and 20 of the RR cells with shRNA and days 10 and 14 of the RR cells treated with siRNA against SETMAR. (G) Western blot for H3K36me2 in parent and RR cells of U87MG and SF268 treated with scrambled, sh1, and siRNA against SETMAR. Total H3 was used as loading control. (H) Representative immunofluorescence images of parent and RR cells treated with scrambled, shRNA, and siRNA against SETMAR stained for Ku80 (green) and nuclei counterstained with DAPI (blue). Graphs represent the quantitation of immunofluorescence of Ku80. Scale bar 10 μm. Results in the bar graph are the composite data from 3 independent experiments.