Effects of Siah1 on Tcf/Lef regulated transcription activity in SKBR3 and MCF-7 cells. A: Transfected cells were cotransfected with Topflash or Fopflash plasmid, the Renilla luciferase reporter plasmid (pRL-TK) as an internal control and the indicated expression plasmids. Luciferase activity was measured at 24 h after transfection and plotted after normalizing with respect to the Renilla luciferase activity. Each experiment was performed at least three times. Columns, mean; bars, SD; *, p < 0.05. B; Functional inhibition of Siah-1 ubiquitin-ligase by siRNA increased TCF/Lef transcriptional activity in MCF-7 cells at 24 hours after transfection. Each experiment was performed three times. Columns, mean; bars, SD; *, Siah1 siRNA vs. both untreated and control siRNA p < 0.05.