CD82 regulates melanoma experimental metastasis in vivo by suppressing U2AF2-mediated CD44 isoform switching. (A) Quantification of tumor loci in liver 20 days post implantation of vector, CD82, scrambled shRNA, shU2AF2, shCD44s and shCD44v8-10 transfected-Lu1205M cells into nude mice. Ten mice were injected under each condition. The livers in each group were collected and sectioned. 6 sections through the center of the liver were examined under dissecting microscopy for the presence of metastatic tumor loci. Western blotting analysis was conducted to determine the levels of CD44v8-10 and CD44s in lysates from implanted tumors. (B) Quantification of primary tumor’s tumorigenic potentials. Data are mean±SEM. n=10. (C) Representative images of H&E staining of liver metastases of vector, CD82, scrambled shRNA, shU2AF2 and shCD44v8-10-transfected Lu1205M cells in mice. T: metastatic tumor. (D) IHC staining of U2AF2, CD44s and CD44v8-10 in invasive fronts of primary tumor.