Figure 2.

Effect of Notch agonist and antagonist treatment, assessed by Hes-1-driven luciferase expression in MCF-7 cells. (a) DSL treatment (100 nM) increased luciferase expression twofold compared with control, whereas treatment with the N4 blocking antibody (N4Ab) or gamma secretase inhibitor (GSI) (5 μM) reduced both endogenous and DSL-induced luciferase expression. (b) Dose–effect of Notch signaling antagonists. The difference in luciferase activity in cells treated with the maximum dose of inhibitory agent and in nontreated cells cells was statistically significant for each of the four different treatments (P < 0.005). The R² values and trendlines for the four sets of experiments are shown.