Figure 3.

NFκB pathway is required for the survival and regrowth of tamoxifen-tolerant cells in vitro and in vivo. A, NFκB pathway inhibitors (IKK7 and DMF) alone or in combination with 4OHT were added to MCF-7 cells treated as described in Fig. 1A. Data was normalized to own controls, each set to 100%. B, MCF-7 cells were treated with 4OHT, IKK7 (1μM), or DMF (20μM) alone or in combination for 2 weeks. After 2 weeks, all drugs were withdrawn and regrowth (% confluence) was monitored by Celigo cell imager. C, MCF-7 xenograft tumor growth curves are shown for mice treated with: vehicle (Veh), DMF, tamoxifen (Tam), and Tam+DMF for 4 weeks, and then monitored for an additional 6 weeks after all therapies were withdrawn. Tumor recurrence between Tam vs Tam+DMF is significantly different, p=0.0015 using a Fisher’s exact test analysis. End point comparison of mean tumor area (length/2 × width × π) for Tam vs Tam+DMF is indicated. ***P<0.001.