Fig. 6

Luteolin reduces expression of angiogenesis markers and PR in breast cancer cell xenograft tumors. a Luteolin suppresses MPA-driven VEGF expression in T47-D xenografts. Xenograft tumor-bearing mice were sacrificed at day 79 and tumors collected, processed, and subjected to immunohistochemistry. Upper panel Images represent VEGF (brown) staining from one tumor per group. Scale bar 100 µM. Lower panel Results represent quantification of VEGF staining (mean ± SEM percent area of staining) [control (placebo pellet + vehicle), n = 3 tumors; MPA (MPA pellet + vehicle), n = 7 tumors; MPA + luteolin (LU) (MPA pellet + LU), n = 8 tumors]. *Significantly different from control (P = 0.007, ANOVA). **Significantly different from MPA (P < 0.001; ANOVA). Inset represents no antibody control. b Luteolin suppresses MPA-driven increases in blood-vessel density in T47-D xenografts. Upper panel Images represent CD31 endothelial staining (reddish-brown) of blood vessels from one tumor per group from sections of a ×20 field at captured resolution. Scale bar 50 µm. Lower panel Results represent quantitation of number of blood vessels stained. Five captures at ×20 were taken per tumor in each group [control (E2 pellet + vehicle), n = 3 tumors; MPA (MPA pellet + vehicle), n = 7 tumors; MPA + LU (MPA pellet + LU), n = 8 tumors]. The number of blood vessels was counted in each tumor capture, averaged for each individual tumor, and the data represent mean number of blood vessels/tumor capture ± SEM. *Significantly different from control (P < 0.001, ANOVA). **Significantly different from control and MPA alone (P = 0.003, ANOVA followed by a Newman–Keuls multiple comparison test). Inset represents no antibody control. Arrows point to blood vessels represented by CD-31 staining. c Luteolin does not restore MPA-driven loss of PR expression in T47-D xenografts. Upper panel Images represent PR staining from one tumor per group [control (placebo pellet + vehicle), n = 3 tumors; MPA (MPA pellet + vehicle), n = 7 tumors; MPA + LU (MPA pellet + LU), n = 8 tumors]. Scale bar 100 µm. Lower panel Results represent quantification of the percent of PR-positively stained cells, means + SEM. *Significantly different from control [P < 0.05, ANOVA on ranks (Kruskal–Wallis), followed by the Newman–Keuls nonparametric multiple comparisons test]. Inset represents no antibody control