FIGURE 2

Elevated expression of p53 in MDA-MB-231 cells is dependent on MAP kinase and independent of mTOR. (a) MDA-MB-231 cells (231 cells) were transfected with either control (Con) GAPDH or PLD2 siRNA as in Figure 1. The levels of phosphorylated MAP kinase (P-MAPK), MAP kinase (MAPK), phosphorylated MEK (P-MEK) and actin were then determined by Western blot analysis. (b) MDA-MB-231 cells were treated with either solvent (dimethyl sulfoxide (DMSO)) or the MAP kinase inhibitor U0126 (Cell Signaling Technology, Danvers, MA, USA) (20  M) for 1 h. The levels of p53, phosphorylated MAP kinase (P-MAPK) and MAPK were then determined by Western blot analysis. (c) MDA-MB-231 cells were treated with either DMSO solvent (0.1%) or rapamycin (Sigma, St Louis, MO, USA) (Rap) (20  M) for 1 h. The levels of p53, phosphorylated S6 kinase (S6K) and S6K were then determined by Western blot analysis. Experiments shown in (a, b and c) are representative of experiments repeated at least two times. Antibodies against MAP kinase, phosphorylated MAP kinase, S6 kinase, phosphorylated S6 kinase and phosphorylated MEK were from Cell Signaling Technology.