Figure 3.

Interaction of PAs with CYP7A1 promoter activity in HepG2 cells. HepG2 cells were cultivated and seeded as described in the materials and methods section. Cells were transfected with the reporter gene plasmid pGL4.14-CYP7A1-Prom (80 ng) and the control plasmid pcDNA3-Rluc (1 ng) for 6 h and subsequently treated with 5, 35, 70, or 250 µM of PA, solvent (Ctr; 2.5% ACN), or positive control (PC, 5 µM of PMA). After an incubation period of 24 h, the cells were lysed, and the firefly and Renilla luciferase activity was detected. The activity of the firefly luciferase was normalized to the activity of the Renilla luciferase and referred to solvent control (= 1) to obtain the x-fold induction. Shown are means ± standard deviations of three independent experiments with three replicates each. Statistical differences were evaluated using one-way ANOVA followed by Dunnett’s test: * p < 0.05, ** p < 0.005, *** p < 0.001. Em, echimidine; Sc, senecionine; Hn, heliotrine; Sk, senkirkine.