Figure 3.

(A) Phase contrast microscopy was used to monitor cells for morphological changes associated with modifying the hexose composition of the culture medium. After 3 weeks, the MDA-MB-468 cells cultured in the fructose-only medium acquired an elongated morphology and displayed a more dispersed growth pattern than cells propagated in glucose or glucose: fructose. In these two media, the cells grew in cobblestone clusters. The timing of changes in cell shape was observed in three independent experiments. (B) Because morphological changes are often related to remodeling of the cytoskeleton, the actin structure of cells was visualized by rhodamine phalloidin fluorescence, using the x40 objective of a Nikon Labophot microscope. Cells cultured in the higher concentration of fructose displayed markedly less actin staining around the cell periphery. F-actin staining was further assessed by scoring for the presence or absence of intense fluorescent staining on the cell periphery in randomly selected microscopic fields on each coverslip. Of the 771 cells cultured in 25 mM glucose, 692 (89.85%) were intensely stained, compared to only 23 (4.8%) of 481 cells grown in high fructose medium (Fisher’s exact test, p<0.0001).