Figure 4

Enzalutamide inhibits androgen-stimulated growth of MDA-MB-453 tumors. MDA-MB-453 cells were injected orthotopically in the mammary gland of female NOD-SCID-IL2Rgc^-/- mice. Three groups had a 5-alpha-dihydrotestosterone (DHT) pellet implanted subcutaneously and one group had no pellet (Vehicle). Once tumors reached an average size of 100 mm³ (green arrow), mice were given either enzalutamide (Enza, 10 mg/kg) or vehicle (Vehicle and DHT groups) by daily oral gavage. Another group was given a higher dose of Enza (25 mg/kg) by oral gavage when tumors reached an average size of 400 mm³ (blue arrow). (A) Tumor volume was measured weekly by caliper. Error bars represent standard error of the mean. *P < 0.05, **P < 0.01 for DHT versus DHT + Enza (10 mg/kg), Wilcoxon rank sum. (B) Tumors were excised and weighed at the end of the experiment. (C) Tumor sections stained for cleaved caspase 3 were quantified (left) and representative images shown (right) (200× magnification). *P < 0.05, **P < 0.01, ***P < 0.001, analysis of variance with Bonferroni’s multiple comparison test correction. (D) Nuclear androgen receptor staining was quantified (left) and representative images (400× magnification) are shown (right). *P < 0.05, ***P < 0.001, Kruskal–Wallis with Dunn’s multiple comparison test correction.