Fig 10.

The first extracellular loop of claudin-2 is required to promote the breast cancer liver-metastatic phenotype. Quantification of the tumor burden (tumor area/tissue area) within the cardiac liver lobe following the splenic injection of the indicated cell populations is shown. The number of mice analyzed in each cohort is indicated in parentheses. Decreases in liver-metastatic burden were observed when the empty vector-, claudin-4-, or C4(C4/C2)-expressing cells, in the context of diminished claudin-2 levels, were injected into the spleen (∗, P < 0.002; ∗∗, P < 0.001; ∗∗∗, P < 0.04). However, the liver-metastatic phenotype was rescued when the C4(C2/C2) or the C4(C2/C4) chimera was expressed. Hematoxylin- and eosin-stained images of the cardiac liver lobe are shown for mice injected with each of the cell populations. Dotted lines circumscribe breast cancer metastatic lesions within the liver. The scale bar represents 2 mm.