Rab13 knockdown reduces tumor growth and migration in vivo. (A) 1833TR cells stably expressing luciferase and either a control vector or shRNAs targeting Rab13 were injected into the tail veins of mice. The panel shows representative bioluminescence images of mice immediately after injection (day 0) and 63 d after injection. See Fig. S3 for all mice used in the study. (B) Tumor take rates of injected mice at day 63. (C) Total bioluminescence of luciferase-positive mice was quantified and normalized to day 0 (mean ± SEM from one independent experiment in which n = 9 for control mice and shRNA 2 and n = 8 for shRNA 1; two-way ANOVA with Tukey’s post-test; *, P < 0.05). (D) Representative hematoxylin and eosin staining of lung tissue collected from mice injected with control cells and Rab13 knockdown cells. Arrowheads indicate tumors. The bottom row corresponds to the areas indicated by the black boxes in the top row. Bars: (top row) 3 mm; (bottom row) 100 µm. (E) Quantification of tumor numbers in D (mean ± SEM from one independent experiment in which n = 10 and n = 18 for control and Rab13 shRNA, respectively; Student’s t test; *, P < 0.05). (F) Injected mice with visible tumors illustrate cell migration outside the lungs. A mouse with no detectable mass is shown for comparison. Bars, 1 cm. (G) The number of mice with a luciferase signal anywhere outside of the lung at day 63 was quantified.