FIGURE 6.

Zinc finger E‐box–binding homeobox 1 (ZEB1)‐Ras regulatory switch downregulates E‐cadherin expression through a novel mechanism. A, PANC‐1 cells were transfected with siRNA against ZEB1 or nonspecific control siRNA (NC). After 24 h of siRNA transfection, cells were transfected with a CDH1 promoter‐reporter construct (CDH1‐Luc) or control vector pGL4‐MLP. Luciferase activity was measured at 27 h after reporter transfection. B, PANC‐1 cells were transfected with siRNA against ZEB1 or nonspecific control siRNA (NC). After 24 h of transfection, cells were treated with phorbol 12‐myristate 13‐acetate (PMA) (10 nmol/L) for 48 h. C, PANC‐1 cells were transfected with CDH1‐Luc or pGL4‐MLP. After 9 h of transfection, cells were treated with PMA (10 nmol/L) for 18 h, and then luciferase activity was measured. D, PANC‐1 cells were treated with PMA (10 nmol/L) with or without actinomycin D (1 µg/mL) or cycloheximide (50 µg/mL) for 8 h. B and D, Expression of CDH1 mRNA was analyzed by quantitative RT‐PCR (triplicate determination). The value in DMSO control is shown as “1.” Data are presented as mean ± SD. **P < 0.01; ***P < 0.001; ns, not significant