Figure 5.

Effect of PTEN knockdown in K562 cells on t-BHQ–mediated histone acetylation, Nrf2 binding to the ARE, and ferritin H and NQO1 mRNA expression. (A) K562 cells (1 × 10⁷) were electroporated with 100 pmol of nontargeting (siControl) and PTEN-targeting siRNA (siPTEN). After 60–70 h of transfection, the cells were treated with 50 μM t-BHQ for 6 h followed by ChIP assays using indicated antibodies. (B) K562 cells (1 × 10⁷) transfected with siControl or siPTEN for 48 h were treated with 10 and 50 μM t-BHQ for 24 h, and 4 μg of total RNA was subjected to ferritin H and NQO1 Northern blot analyses. RNA staining with ethidium bromide is shown for comparative loading of RNA. In both A and B, 20 and 2 μg of whole cell lysates isolated in the same experiment were analyzed by Western blotting using anti-PTEN and anti-β-actin antibodies, respectively. Representative results and the -fold increase in mRNA expression by densitometry are shown from two independent experiments.