Comparison of the degree of contact guidance between tumor cells and normal cells in vitro.

A comparison was made between the degree of contact guidance produced by grooved or ridged substrata in cultures of normal mouse embryonic fibroblasts and in fibrosarcoma EMT6 cells or cells of a dibenzanthracene-induced fibrosarcoma. Normal mouse mammary epithelial cells were also compared with cells of C3HBA mammary tumor. All types of cell showed a highly significant orientation in the direction of the grooves or ridges, but there were significantly lower proportions of aligned tumor cells than of their normal counterparts. Fibroblasts showed more alignment than did normal mammary epithelial cells, and the sarcoma cells showed more alignment than did the C3HBA tumor cells. Scanning electron microscopy of cells growing on ridged substrata revealed that all types of cells adhere to the ridges rather than to flat areas between ridges. The difference between normal and malignant cells appears to indicate a real difference in a behavioral characteristic, namely, that tumor cells are less responsive to the topographical features of the substratum that are their normal counterparts. The local infiltration of tissues by tumor cells is due to factors other than contact guidance, for it occurs in spite of their lower contact guidance compared to that of normal cells.