Fig. 3. Treatment with P7170 inhibits growth of anti-estrogen-sensitive MCF-7 tumors.

A) Mice bearing MCF-7 xenografts ~200 mm³ were randomized to the indicated treatments. Tumor volumes were calculated relative to baseline volume of individual mice, and mean % baseline volumes + SEM are shown. Data were analyzed by mixed modeling, which revealed that tumor volumes significantly changed over time and due to treatment, and the effects of treatments varied over time (all p<0.0001). All treatment groups exhibited significantly (p≤0.05) reduced tumor volume compared to vehicle control at the 3-wk time point or earlier by t-test with Sidak-Bonferroni multiple testing correction. *p<0.05, **p<0.01 when comparing fulvestrant vs. fulvestrant/P7170 at each time point. ^#p<0.05 when comparing low-vs. high-dose P7170 at each time point. B) Lysates from tumors harvested after 3 days of treatment were analyzed by immunoblot using the indicated antibodies. All lanes were taken from same film and are exposure-matched. C) Tumors harvested after 6 weeks of treatment were analyzed by H&E staining, Ki67 IHC, and TUNEL. Representative images are shown. Scale bar = 40 μm. D-E) Quantification of fractions of Ki67+ and TUNEL+ tumor cells from (C). Horizontal bars indicate median values within each treatment group. *p≤0.05, ^#p=0.07, ^##p=0.1 by Bonferroni post-hoc test vs. vehicle control, unless otherwise indicated by brackets.