FIGURE 1.

siRNA-mediated knockdown of Pdcd4 up-regulates p53 expression. A, Western blot analysis of HeLa cells (WT) and two stable Pdcd4 knockdown clones (K11 and K12). The Western blots were developed with antisera against Pdcd4, p53, and β-actin as indicated. Cells were grown in normal growth medium or in medium supplemented with 10 μm proteasome inhibitor MG132 for 4 h before harvesting. B, HeLa cells were transiently transfected with control siRNA or with two different Pdcd4-specific siRNAs. Cell extracts were analyzed by Western blotting for the expression of Pdcd4, p53, and β-actin. C, HepG2 cells were transiently transfected with control siRNA or with two different Pdcd4-specific siRNAs. Cells were treated with or without the proteasome inhibitor MG132 as indicated, and cell extracts were analyzed by Western blotting for the expression of Pdcd4, p53, and β-actin. D, total RNA isolated from siRNA-transfected HepG2 cells was analyzed by quantitative real-time PCR for the expression of p53 (black bars) and Pdcd4 (white bars) mRNAs. E, the nuclear-cytoplasmic distribution of p53 mRNA in HepG2 cells transfected with control or Pdcd4-specific siRNAs was analyzed by real-time PCR.