Figure 1. Macrophage recruitment and polarization following radiation therapy.
A) Orthotopic MMTV-PyMT-derived explant tumors were grown to a median diameter of 1.0 cm, at which time tumor-bearing mice were enrolled in the experiment. One day later they received localized gamma irradiation (5 Gy), and total tumor burden/animal was then assessed every 3 days until endpoint. Treatment schematic is depicted at top and data are displayed as mean tumor burden ± SEM (>8 mice/group). Statistical significance was determined by two-way ANOVA. One of two experiments is shown. B) Quantification of CD45+ (left) and CD11b+F4/80+ (right) cells in mammary tumors on day 2, 4, and 14 following RT (5 Gy) compared to unirradiated tumors harvested on Day 14. Data are depicted as mean number of CD45+ cells as a % of total cells ± SEM as analyzed by flow cytometry (>5 mice/group). Statistical significance was determined by an unpaired t-test. C) CD45+CD11b+F4/80+ macrophages (MØ) were FACS sorted from orthotopic PyMT-derived tumors at Days 1 and 10 following treatment with RT (5 Gy). mRNA expression from sorted cells was analyzed using quantitative real-time PCR for the indicated genes. Treatment schematic is depicted at top and data are expressed as mean fold-change ± SD compared to untreated tumors (4 mice/group). Statistical significance was determined by an unpaired t-test relative to untreated controls, or between Day 1 and Day 10 as indicated. For all panels, statistical significance is shown as *p < 0.05, **p < 0.01, ***p < 0.001.