INPP4B suppresses PC-3 invasion in vivo . (A) PC-3 cells expressing inducible INPP4B (Clone #14) were incubated in the presence or absence of doxycycline (Dox) and labeled with CellTracker Green. Single cell suspension (~5 μL of 2.5×106 cell/mL) was inoculated into the CAM mesoderm of day 10 embryos developing ex ovo. On day 6 after inoculations, microtumor bearing embryos were injected with Rhodamine-conjugated LCA to highlight the CAM vasculature (red). Portions of the CAM containing microtumors were excised and imaged. Microtumor borders and invasion distances of green fluorescent tumor cells are indicated by white dotted lines. Scale bar, 50 μm. (B) Quantification of mean invasion distance. (C) Quantification of maximal invasion distance (mean of 3 maximal invasion distances). One of two independent experiments is shown. Quantitative analysis was performed on 9-16 microtumors, with 3-5 embryos per variant. Data are presented as means ± SEM. ***P < 0.0001, two-tailed Student’s t test.