Change in HER2 expression modulates the effect of (PEITC). (A) Effect of PEITC in HER2-silenced MDA-MB-231 cells. At 48 h after transfection of cells with HER2 siRNA, cells were treated with or without 10 μM PEITC for 24 h. Whole cell lysate was evaluated for phosphorylation of signal transducer and activator of transcription 3 (STAT3), cleavage of caspase 3 and poly-ADP ribose polymerase (PARP). (B) Effect of transient HER2 overexpression on apoptosis induction in MCF-7 by PEITC treatment. After 48 h of HER2 transfection, cells were treated with or without 10 μM PEITC for 24 h. The means of two independent experiments performed in duplicate are shown.