Contact inhibition of what? An analytical review

摘要: Quite a number of phenomena having to do with cells' influences upon one another's movements have come be regarded as expressions “contact inhibition.” However, no single, central mechanism has been shown underlie them all. Consequently, the term inhibition” should not used without operational modifiers. Inhibitions individual cell imputed mediated by cell-cell contacts include inhibition overlapping (which results in monolayering), colony expansion, speed (nuclear translocation), ruffling, orthogonal movement (proposed explain spontaneous parallel alignment cells), and neighbor exchanges. The six inhibitions listed above are operationally distinct, only two (overlapping expansion) known result from common mechanism. A seventh phenomenon, so-called division” (more termed postconfluence division) is separate category considered here. Evidence eliminating action-at-a-distance available for first three, hence these at present contact inhibitions. Inhibition exchanges yet hypothetical; its extreme, it would immobilize cells confluent monolayer, but such immobilization found occur. Contact overlapping, most studied six, displayed invasive respect normal cells; tumor overlap freely cells, although necessarily another. Contact loss can readily interpreted, means differential adhesion hypothesis, consequences cell-type-specific differences cell-substratum “strengths adhesion.” These strengths formulated specific interfacial free energies, which parameters cellular adhesiveness that rigorously determine equilibrium configurations populations.