Figure 6.

PPM1D silencing-induced K-1 cell apoptosis is suppressed by p38 inhibition. (A) K-1 cells treated with or without SB203580 were collected after transfection with siRNA specific to PPM1D. Apoptosis of K-1 cells was detected by flow cytometry. (a-c) Representative plots presenting Annexin V/PI staining. (a) NC, (b) PPM1D-1 siRNA-transfected, (c) PPM1D-1 siRNA-transfected + SB203580. (B) Analysis of apoptotic (early and late) cells from A. Values are expressed as the mean ± SEM of three independent experiments. P-values were determined using ANOVA test followed by Tukey's post hoc test. ***P<0.001. (C) Western blot analysis was performed to confirm the protein knockdown and pharmacological inhibition of p38. Actin was served as a loading control. The relative quantification of protein bands as the ratio to their loading control were presented at the bottom of the western blotting. PPM1D, protein phosphatase, Mg²⁺/Mn²⁺ dependent, 1D; NC, negative control (scrambled siRNA); siRNA, small interfering RNA; PI, propidium iodide.