FIGURE 3.
G2 delay during endoplasmic reticulum stress is enhanced in p53 mutant cells. A, representative FACS histograms of HCT116 cells of the indicated genotypes expressing either scrambled or CHK1 shRNAi and treated with thapsigargin (500 nm) for 0, 16, or 24 h; permeabilized; and then stained with propidium iodide. B, cell lysates were prepared from HCT116 cells of the indicated genotypes expressing either scrambled or CHK1 shRNAi. These were separated by 10% SDS-PAGE, transferred to nitrocellulose, and immunoblotted for total CHK1. eFI2α served as a loading control. C, graphs of G2/G1 normalized to untreated cells from A. Data are mean ± S.E. (error bars). n = 5; *, p < 0.05. D, graphs of sub-G1 cells from A. Data are mean ± S.E. (error bars). n = 5; *, p < 0.05. E, experiments were repeated identically, but cells were stained with propidium iodide without prior fixation to identify late cell death. Data are mean ± S.E. (error bars). n = 5; *, p < 0.05. F, representative FACS histograms of p53 wild type HCT116 cells expressing either scrambled or CHK1 shRNAi and treated with thapsigargin (500 nm) for 0, 16, or 24 h; permeabilized; and then stained with propidium iodide. G, graphs of G2/G1 normalized to untreated cells from F. Data are mean ± S.E. (error bars). n = 3; *, p < 0.05.