Iron metabolism and cell membranes. III. Iron-induced alterations in HeLa cells

The morphologic characteristics of acute iron loading were studied in HeLa cells incubated in an iron-enriched Eagle's medium containing 500 mug/ml of iron. Chemical studies showed that ferritin synthesis was rapidly induced and the concentration of intracellular ferritin increased up to 72 hours. Closely coupled with an increase in HeLa cell ferritin was a marked decrease in the rate of cell multiplication. The significant ultrastructural findings of iron-induced HeLa cell injury are characterized by the appearance of both autophagic multivesicular and residual bodies over the first 72 hours of iron incubation. The prominence of multivesicular bodies was noted after only 4 hours' incubation, with iron and myelin figures first appearing after 6 hours. Thus, the partial arrest of cell multiplication was associated with an increase in cytoplasmic residual bodies containing iron and other debris. The distribution of intracellular ferritin within HeLa cells differs significantly from the distribution described previously in hepatic parenchymal cells. In HeLa cells, ferritin particles were confined to lysosomal vesicles and were not identified in cell sap, endoplasmic reticulum, or Golgi apparatus.