Figure 6

In vivo metastasis analysis via tail vein injection assays and mammary fat pad injection assays. Using the tail vein, nude mice were inoculated with Met wild-type cells and Met-As cells. The lungs of these mice were dissected at 6 weeks and were subjected to whole mount hemotoxylin staining. (a) Lungs of mice injected with 1 × 10⁶ Met wild-type cells were nearly completely infiltrated with metastatic foci (dark regions). (b) Lungs of mice injected with 1 × 10⁶ Met-As cells were free of metastatic foci. (c) Lung cavities of mice injected with 1 × 10⁶ Met wild-type cells were filled with grossly visible metastatic foci. (d) Met cells and Met-As cells were injected in the mammary fat pad of FVB mice. Whole mount analysis of the lungs was performed 42 days after injection. One hundred percent of the Met animals had metastasis (n = 6), while metastasis was not seen in any of the Met-As animals (n = 10). In contrast, in the Db group, two out of nine animals (22%) had metastasis, and the Db-S group had a similar rate of metastasis (two out of 10 animals [20%]).