The influence of tubulin-binding agents on the infiltration of murine MB6A lymphosarcoma and TA3 mammary carcinoma cells into primary rat hepatocyte cultures was studied. Colchicine, nocodazole and vinblastine reduced the number of infiltrating lymphosarcoma cells, probably by interfering with the adhesion of these cells to the exposed hepatocyte surface. However, the subsequent infiltration of cells that did adhere was not affected or even slightly stimulated. The reduced adhesion appears to be due to an effect on both the MB6A cells and the hepatocytes. In contrasts, adhesion of TA3 cells was not reduced and infiltration was markedly enhanced by these agents, due to an effect on the TA3 cells but probably not on the hepatocytes. These observations support previously described morphological evidence for differences between the infiltration mechanisms of the two tumour cell types. It is concluded that the system within the hepatocytes involved in adhesiveness of the exposed surface to MB6A cells is distinct from that mediating other types of adhesion. The tendency of TA3 cells to invaginate hepatocytes may be due to disturbances in tubulin-dependent processes.
Evaluation of Antivascular and Antimitotic Effects of Tubulin Binding Agents in Solid Tumor Therapy