Altered organization of cell-substrate contacts and membrane-associated cytoskeleton in tumor cell variants exhibiting different metastatic capabilities.

The pattern of cell-substrate attachment and the organization of actin-containing microfilament bundles were analyzed in tumor cell variants of the K-1735 melanoma and UV-2237 fibrosarcoma series exhibiting distinct metastatic phenotypes. In both tumors, the low-metastatic cells were relatively flat, with well-developed focal contacts. Visualization of the cellular organization of actin and vinculin by fluorescence microscopy indicated that the low-metastatic cells contained prominent stress fibers which terminated in large vinculin-containing focal contacts. The high-metastatic cells were characterized by poor organization of vinculin and adhesion plaques as well as by low number and disarray of actin bundles. These results are compatible with the notion that cytoskeletal organization may be involved in cytodynamic processes related to tumor cell dissemination and implantation.