Invasiveness of carcinomas was connected early to decreased cohesiveness and has more recently been associated with loss or decreased activity of E-cadherin. In the first thermodynamic measurements of cohesive intensities among malignant cells, we here find the cohesive intensities of Lewis lung carcinoma cells to fall within the range measured previously for cells from a series of noninvasive embryonic tissues. Thus, too-low cohesiveness is itself an insufficient explanation for invasiveness. Nevertheless, transfection-mediated cadherin expression sufficient to increase cohesiveness by as little as 26% suffices to greatly reduce invasion of aggregates of Lewis lung carcinoma cells into Matrigel. This property is not restricted to E-cadherin but is shared by P-cadherin. The same cadherin-transfected cells do not display this invasion suppression when plated sparsely, indicating that invasion-suppression activity of cadherins requires cell-cell contact. These facts are consistent with the invasion-suppression activity of cadherins resulting either from the physical restraint of increased cohesion per se or from another cadherin activity mediated through cell-cell contact.
This work was supported by NIH Grants GM52009 from the National Institute of General Medical Sciences and HD30345 from the National Institute of Child Health and Human Development.