Figure 4
Snail can negatively regulate maspin promoter activity. (A) Analysis of maspin promoter region with ConSite software revealed 8 E-boxes. 22Rv1 cell lines stably overexpressing Snail (Snail-high clone) or vector control (Neo) or C4-2 cells with stable Snail knockdown (C4-2 E8) or non-silencing control (C4-2 NS) were plated at 6 x 105 cells/well in 6-well dishes overnight in hormone-depleted media. Cells were subsequently transfected with 3 μg of DNA from the full-length maspin promoter reporter plasmid and an internal control plasmid (renilla luciferase for transfection efficiency) using Lipofectamine 2000. After 48 h, analysis of luciferase activity relative to renalla luciferase activity showed that (B) maspin promoter activity was decreased in 22Rv1 cells overexpressing Snail and (C) maspin promoter activity was increased in C4-2 cells with stable Snail knockdown. The experiments were performed in triplicate at least three times independently. Bars, SD *, P < 0.05, Student’s t test compared with control.