The establishment and characterization of a new balb/c angiosarcoma tumor system

A BALB‐3T3/A31 untransformed cloned cell line and 3 selected variants derived from this parental cell line, expressing 3 increasingly malignant phenotypes, have been established and characterized in vivo and in culture. This new tumor series, identified as angiosarcoma, consists of an anchorage‐independent nontumorigenic cell clone and 2 sublines exhibiting tumorigenic and metastatic properties. Morphological examination revealed that the 3 transformed cell variants differed from the normal parental cells and were not contact‐inhibited. Karyotype and rate of cell proliferation in culture were similar for all the cell variants. Cytoskeletal visualization by immunofluorescence staining revealed that the tumorigenic and metastatic cell lines expressed an altered organization of actin cables and a smaller number of vinculin‐containing focal contacts. Lactoperoxidase iodination of cell surface proteins showed the appearance of an M_γ 86,000 protein in the tumorigenic and metastatic cell variants. Analysis of cell‐surface glycoproteins demonstrated an increased sialylation of M_γ 66,000 and M_γ 62,000 glycoproteins in the transformed, tumorigenic and metastatic cell lines. This angiosarcoma tumor model system allows investigation of cellular characteristics which might be relevant to specific stages in tumor progression.