Figure 5.

FLT1 inhibition blocks breast cancer metastatic growth. (a) Spontaneous metastasis assay of F246-6 cells with antibody treatment after tumor resection. (b) Stereological quantification of metastasis index (the same as in Fig. 1). Data show mean + SEM. n ≥ 13; **, P < 0.01 by Student’s t test. (c) Survival curve of mice treated with control or MF1 antibodies. Death is defined when the mice became moribund. n ≥ 10; P = 0.0136 by log-rank test. (d) Representative immunohistograms of the indicated immune cell type showing fluorescent intensity of FLT1 (red) and isotype control (blue) staining. n = 3. (e) Mean fluorescent intensity of FLT1 expression in MAMs and lung-resident macrophages. n = 3; ***, P < 0.001 using two-way ANOVA followed by Šídák’s multiple comparisons test. (f) Percentage of MAMs (F4/80⁺CD11b⁺ and Gr1⁻) in total hematopoietic cells in perfused lung 24 h after Ctrl Ab or MF1 administration. n ≥ 3; not significant by Student’s t test. (g) Percentage of major immune cell populations in total hematopoietic cells in perfused lungs 24 h after Ctrl Ab or MF1 administration. n = 3; not significant by Student’s t test. (e–g) Error bars indicate SEM. (h) Representative Western blot after IP of FLT1 and probing using the p-Tyr antibody in primary macrophages showing phospho-FLT1 (top) and total FLT1 (bottom) treated with the indicated growth factor or tumor cell condition medium. n = 3.