Figure 2. Estrogen receptor antagonism increases α-Lactalbumin promoter expression in breast tumors.

T47D-hLac-Luc (expressing luciferase under control of the human α-Lactalbumin promoter) or T47D-hBAct-Luc (expressing luciferase under control of the human β-Actin promoter) breast cancer cells were treated with Tamoxifen and Fulvestrant. Luminescence reading from treated cells were normalized to luminescence from untreated cells at each time point to obtain fold increase (n = 3 replicate experiments). Greater than 2 fold increase in α-Lactalbumin promoter activity was observed after treatment with Tamoxifen (A; p < 0.01 with 0.01 mM; p < 0.001 with 0.1 mM at 96 hours) and Fulvestrant (C, p < 0.01 with 0.1 μM at 36 hours; p < 0.1 at 48 hours). No increase in β-Actin promoter driven luminescence was observed after treatment with Tamoxifen (B) or Fulvestrant (D).