Structural anomalies of highly malignant respiratory tract epithelial cells
Manger, R.L.; Heckman, C.A.
Cancer Research 42(11): 4591-4599
1982
ISSN/ISBN: 0008-5472 PMID: 6751525 Document Number: 188053
Studies were designed to determine whether cytostructural changes were related to malignancy and the loss of growth control in epithelial cells. Three highly malignant cell lines [MCA-7, B2-1 and BP3-0] were derived from transplantable carcinomas of the rat respiratory tract and compared with 3 respiratory tract epithelial lines [rat tracheal 1655 cells, 2Cl cell and 4C9 cells] of negligible malignancy. Keratin cytoskeletons were visualized by indirect immunofluorescence staining, and sample photomicrographs representing each line were prepared. Observers naive to the immunofluorescent images were asked to classify the encoded photomicrographs into 6 groups, corresponding to the cell lines, and then into 2 major classes, each containing 3 of the original groups. The criteria used in making the classifications were recorded and analyzed to identify the features common to the highly malignant lines. These included the nonuniform spacing of cells in the field of view, the cell shape, and the presence of nonfluorescent areas in the lamellar cytoplasm. The criteria that were not useful for discriminating between images from the malignant lines and those of negligible malignancy were the cell size, the prominence and structure of the filaments and their integration into desmosomes, and the appearance of the nucleus. Since the nonuniformity of keratin distribution in the periphery of the malignant cells suggested a structural anomaly, the cell lines were also examined by scanning electron microscopy. Unlike cells from the lines of negligible malignancy, cells from 2 of the highly malignant lines showed thickenings in the subterminal portions of the lamellar cytoplasm. Specific architectural changes at the cellular level might be linked to the process of epithelial transformation and tumor progression.