Transfection of ANT2 shRNA leads to JNK activation and subsequent up-regulation and activation of p53 in MCF7 cells. (A) Analysis of ATP levels in lysates of MCF7 cells pre-treated with the JNK inhibitor SP600125 for 2 h and then transfected with scrambled or ANT2 shRNA for 24 h. The data are shown in relative luminescence units (RLU) calculated by normalizing total intracellular ATP to total protein. (B) MCF7 cells treated as in (A) were analyzed for JNK phosphorylation by immunoblotting using anti-phospho JNK and anti-JNK antibodies. (C) Effect of JNK inhibition on ANT2 shRNA-mediated upregulation of DR4 and DR5. MCF7 cells were treated with SP600125 and scrambled or ANT2 shRNA as in (A). Cell extracts were subjected to SDS-PAGE and immunoblotted with antibodies against phospho-p53, p53, DR4, DR5, and β-actin (control).