Figure 7.

Mitochondrial damage caused by E protein in SW480 cells. (A) SW480 parental cells and SW480/12/E before and 24, 48, and 72 hours after Dox induction were stained with DiOC6, and analyzed by flow cytometry to determine the mitochondrial membrane potential (ΔΨm) disruption caused by E gene expression. Data shown are representative results from four independent experiments. (B) Ultrastructural analysis showed that the morphology of SW480/12/E cells not induced by Dox was similar to that of SW480 parental cells, with a typical presence of a large nucleus and light cytoplasmic complexion containing well-preserved organelles including mitochondria (a, 2000×). In contrast, E gene expression in SW480/12/E after Dox exposure generated a large number of altered mitochondria with disrupted cristae (b, 6000×). These cells eventually presented noticeably dilated mitochondria (c, 12,000×). Furthermore, mitochondrial changes in some cells were accompanied by the presence of dilated smooth endoplasmic reticulum (d, 9000×), and the presence of clusters of intermediate filaments (e, 4000×).