Fig. 1
Interactions between activated microglia and metastatic breast carcinoma cells. a MDA-MB-231-DsRed cells were implanted under the imaging window in Cx3cr1GFP/+ mice as described in Methods, mice allowed to recover, and cells visualised under anaesthesia using adapted multiphoton microscope. b Representative images of activated microglia (green) and breast cancer cells (red) 5 (i) and 7 days post-implantation (ii). Asterisks in main image indicate cells in 2X magnified images on right. Scale bars, 50 μm and 25 μm, respectively. Arrowheads indicate direct interactions between microglia and tumour cells. Arrows indicate elongate neurite-like processes on tumour cells. c Example cellular interactions from additional mice 5 (i) and 7 days post-implantation (ii). d Number of microglial interactions per cancer cell 5 and 7 days post-implantation (n = 8 fields of view/time point). e Density of GFP-positive cells in the presence/absence of cancer cells (n ≥ 5 fields of view/time point). f Sholl analysis plot of microglia imaged from mice in which cancer cells had been implanted compared to mice in which no cancer cells had been implanted (n ≥ 20 cells/group). g Maximum branch length (μm) of microglia imaged from mice in which cancer cells had been implanted compared to mice in which no cancer cells had been implanted (n ≥ 20 cells/group). h Schoenen ramification index of microglia imaged from mice in which cancer cells had been implanted compared to mice in which no cancer cells had been implanted (n ≥ 20 cells/group). Box plots show median, 25th and 75th percentile values; whiskers are minimum and maximum values. **P < 0.01; ***P < 0.001; Mann-Whitney test for (d) and Kruskal-Wallis with Dunn’s post hoc test for (e), (g) and (h)