Figure 6. Fractionation of hTERT-eGFP MCF7 cells by cell size allows the separation of larger and smaller cell sub-populations, with distinct metabolic functional properties.

We fractionated MCF7-hTERT-eGFP cells based on forward/side scatter into larger and smaller cell populations. Note that larger MCF7 cells showed a 2.65-fold increase in hTERT-eGFP fluorescence, as compared with the smaller cell population. Similarly, larger cells also showed a 1.6-fold increase in mitochondrial mass (MitoTracker Deep-Red) and a 2.4-fold increase in mitochondrial activity (membrane potential), as measured using MitoTracker Orange. Thus, larger cell size directly correlates with telomerase activity and mitochondrial mass/activity, which would be consistent with an anabolic CSC phenotype.