Figure 1.

Electron microscopy shows that fibroblasts in co-culture display increased autophagy and MCF7 cells exhibit abundant mitochondria. To monitor the status of autophagy, hTERT-fibroblasts and MCF7 cells were co-cultured for three days, fixed and evaluated by electron microscopy. (A and B) Co-cultured fibroblasts display numerous lysosomes and autophagosomes. (A) The EM image represents a fibroblast with numerous lysosomes (arrows) and autophagosomes (boxed area). (B) The higher magnification of the boxed area depicts an autophagosome. Note that the autophagosome shows (i) a double-membrane (arrowhead) and (ii) organelles within that appear to be degraded mitochondria (arrows). Bars = 1 µm for (A); = 0.2 µm for (B). (C) Co-cultured MCF7 cells exhibit the presence of many mitochondria. Note that co-cultured MCF7 cells exhibit the presence of many mitochondria (arrows) and of intermediate keratin filaments (demonstrating their epithelial origin). N, nucleus.