ATM inhibition abolishes the PIM-2 protective effect regardless of E2F-1 expression.
A, cell cycle FACS analysis (propidium iodide-stained cells) of cells overexpressing PIM-2 (+DOX), compared with (−DOX) control cells, under conditions of E2F-1 silencing (E2F-1 siRNA no.1) or nonspecific siRNA, with or without the ATM inhibitor KU55933 (10 μm), 6 h post-UVC radiation (15 mJ/cm2). The horizontal line in each pattern indicates the channels included in calculation of the sub-G1 phase. The percentage of sub-G1 cells is written above the horizontal line. B, percentage of cells at the sub-G1 phase, calculated from cell cycle patterns such as that presented in A with both E2F-1 siRNA sets (no.1 and no.2). C, Western blot analysis (40 μg of total protein extract) for E2F-1 and phosphorylated Kap1 on Ser-824 (pKap1) levels, in cells treated as described in A. Anti-tubulin was used for equal loading control and normalization.