Cell membranes after malignant transformation. Part I: Dynamic stability at low surface tension

A hydrodynamic cell model is introduced to analyze the dynamic stability of the cell membrane after malignant transformation. The cell membrane is considered as a two-dimensional charged interface between intra- and extra-cellular fluids. Employing a first order stability analysis, conditions are established under which growth of surface fluctuations can occur (leading to microvilli formation or cell division). The system is unstable if the total surface tension, i.e. the pure surface tension plus the free energy of formation of the double layers, is negative. Following that criterion, cell division is promoted in cancer cells; moreover, as cancer cells are more fluid than normal cells, they will divide more rapidly. The model also predicts that microvilli (protrusions of the cell membrane) will have a diameter of the order of the dominant wavelengths of perturbation (0.1 - 1 mu) which supports the view that such protrusions are consequences of amplified cell surface fluctuations.