FIGURE 6.

Knockdown of HEXIM1 inhibits the induction of p53. A, MCF7 cells were transiently transfected with a control (i.e. shCon) or a HEXIM1 (i.e. shH1) shRNA in the absence or presence of MG132. Expression of the indicated proteins was analyzed by Western blotting. Actin and p27 were used as negative controls. B, MCF7 cells were transiently transfected by an indicated shRNA plasmid. Two days after transfection, cells were incubated with 1 μm of doxorubicin (Dox) or flavopiridol (Flavo) for 3 h before harvesting. The DMSO-treated cells were used as controls since both Dox and Flavo were dissolved in DMSO. Expression of p53, HEXIM1, Puma, p21, p27, and actin proteins was analyzed by immunoblotting. Actin and p27 were used as controls.