Rapid induction of morphological changes in human carcinoma cells A-431 by epidermal growth factors.

Abstract

The morphological effects of epidermal growth factor (EGF) on human carcinoma cells A-431 were examined by scanning electron microscopy. These flat polygonal cells normally exhibit only small membrane folds, but show extensive ruffling and extension of filopodia within 5 min of exposure to EGF at 37.degree. C. This ruffling activity is transient, subsiding within another 5-15 min, but several other changes in surface morphology follow. Within the 1st h of exposure to the hormone, the cell surface becomes exceedingly smooth and the nuclei seem to protrude above the plane of the otherwise thin monolayer, giving the cells a fried egg appearance. Cells at the edges of colonies gradually retract from the substrate, leading to reorganization, by 12 h, of the monolayer into multilayered colonies. EGF thus induces rapid and long-term alterations in the morphology of these epidermoid cells.