Figure 4.

Akt induces HCCR-1 overexpression by increasing its promoter activity in PANC-1 cells. A) Stable transfectants with two types of constitutively active Akt (CA-Akt1 or 2) induced HCCR-1 expression (lane3,4), whereas dominant negative Akt mutants (DN-Akt1 or 2) failed to induce its expression(lane1,2), compared with vector control(lane5,6). Akt is a doublet protein as shown in the figure. Tubulin, an equivalent loading control of proteins in western blot assays. B) Akt transactivates the promoter activity of HCCR-1. The transfectants applied in Fig. 4A were co-transfected with reporter plasmids containing three different constructs of HCCR-1 promoter (for details, see Materials and Methods) and internal control vector. The promoter activity of both pGL3/HCCR-1-P1196 and pGL3/HCCR-1-P504 constructs was enhanced by a constitutively active form of Akt whereas it was down-regulated by a dominant negative mutant form of Akt (P < 0.05, multiple factor ANOVA), and this was not found in the pGL3/HCCR-1-P423 construct. The data are expressed as the mean ± SEM of three separate experiments.