Apoptosis and epithelial phagocytosis in mitomycin C-treated human pulmonary adenocarcinoma A549 cells

Fate of human cancer cells damaged by mitomycin C was investigated by elect ron microscopy, In a monolayer culture of pulmonary adenocarcinoma A549 cel ls, the antitumor drug mitomycin C induced dilation of the smooth endoplasm ic reticulum and Golgi apparatus. Simultaneously, the myelin figures, autop hagosomes and dense tonofilament bundles were formed in the cytosol. Nuclea r changes also included nucleolar condensation, as well as the disappearanc e of the karyosomes and thinned marginal heterochromatins. These nuclei cam e to be rigid and densely chromatic, finally resulting in apoptosis. There was no alteration in the mitochondria or rough endoplasmic reticulum. Meanw hile, some remaining intact A549 cells extended their cytoplasm toward deta ched cells and engulfed them. These results indicate that mitomycin C induc es apoptosis in A549 cells and concurrently stimulates epithelial phagocyto tic activity against their own damaged cells. (C) 2001 Harcourt Publishers Ltd.