Behavioral anomalies of highly malignant respiratory tract epithelial cells

In previous work, we undertook a comparison of cells from three highly malignant in vitro epithelial lines with cells from three lines showing little or no evidence of tumorigenicity, to see if consistent structural perturbations were present. Cells from highly malignant lines showed common anomalies in the organization of the lamellar cytoplasm. The objective of the present studies was to determine whether these anomalies were correlated with common adhesive or motile properties of the cells. The cells were cultured in a special chamber on the stage of an inverted microscope, and their movements were recorded by a time-lapse video process. Cells selected at the 24.0-hr interval after plating were subjected to a progressive analysis of movement by entering their sequential positions on the digitizing tablet of a Videoplan image analyzer. For each frame analyzed, representing a 15-min real-time interval, the distance traveled and the angle of travel relative to a fixed axis were measured, and the extent of contact between the subject cell and its neighbors was estimated. For the great majority of cells, the direction of translocative movement was random. The mean velocities were in the range of 17 to 60 mum/hr and tended to be greater for cells from the highly malignant lines. Although the frequency of cell-cell contact varied little among lines, the frequency of cells overlapping during contact was much greater for lines of high malignant potential than for lines of negligible tumorigenicity. Striking differences were observed in the behavior of cells plated on glass and plastic substrata. While cells from lines of negligible tumorigenicity adhered well to both substrates, cells from all of the three highly malignant lines became rounded or formed spheroidal masses when plated on glass surfaces. The results indicated that gradations of adhesive, although not necessarily motile, properties were correlated with gradations of tumorigenicity in these epithelial model systems.