Cellular motility on glass and in tissues: similarities and dissimilarities

Four neoplastic cell populations, two leukaemias and two carcinomas, were compared with regard to their motile behaviour on glass, on the surface of, and within the mesentery. This natural membrane was chosen because cells with invasive capacities can penetrate into its loose connective tissue where their movements were recorded by time lapse cinematography. Scanning electron microscopy was utilized to better visualize shape and surface specializations of cells moving in the three localizations. Analysis of time lapse films have shown that two populations, the L5222 rat leukaemia and the V2 carcinoma of the rabbit, contain cells with translocative motility. The non-locomotive cells of these populations and all cells of the other two populations (the BNML rat leukaemia and the human tongue carcinoma cell line LICR-HN1) exhibited stationary (non-translocative) motility. These basic patterns of cell motility remained the same irrespective of the environment. Regarding the influence of the structured elements of the loose connective tissue on overall shape and surface features, it was found that cells from the two leukaemias were the least affected. While BNML cells displayed their non-locomotive activity in a spherical configuration, the translocative L5222 cells migrated in the same shape as on glass. The anterior cytoplasmic extensions, however, were smaller and less variable. The two carcinoma cell populations were more influenced in both shape and cytoplasmic extensions. The well-spread configuration assumed by the stationary LICR-HN1 cells on glass was not maintained in the tissue. There the cells were more spherical. V2 carcinoma cells locomoting within the mesentery showed an increased ability to adapt their shape to the structured environment. The large leading lamellae, characteristic for V2 cells moving on glass, were not evident in the mesentery. They were replaced by smaller and longer cytoplasmic extensions. These observations indicate that the display of cellular locomotion as such does not depend on the environment. The latter, however, can induce adaptations of the cells' locomotive machinery which are expressed as modifications of overall shape and surface features.