TNS1 and osteosarcoma: Immunostaining of U2OS osteosarcoma cells or telomerase-immortalized fibroblasts (TIFs) with antibodies specific for the different tensin isoforms (for the characterization of antibody specificity see Fig. S1 C) revealed that both cell types expressed tensin1 and tensin3, but little tensin2 (Fig. S1 D).