Figure 3

FDG uptake of CSCs and of adherent cells. Single cell suspensions were incubated with 0.75 MBq/mL of FDG at 37°C. At 15, 30 and 60 min, samples were collected and radioactivity of the pellet and supernatant was measured in a radioisotope calibrator well counter. Results are reported as the percentage of cell radioactivity associated with the total radioactivity added, normalized per million of cells. (A) Uptake of FDG in CSCs, SAR-OS and MNNG/HOS cells. At 60 min, the cellular uptake of FDG in CSCs was of 4-fold lower than that in both adherent MNNG/HOS and SAR-OS cells. (B) Uptake of FDG during differentiation of CSCs. FDG uptake increased progressively with the number of days of culture of CSCs in differentiating conditions, acquiring a metabolic profile similar to that of MNNG/HOS cells after 19 days. Data are shown as the mean ± standard deviation of four (n = 4, A) and three (n = 3, B) independent experiments performed in triplicate. *p < 0.05 as compared with CSCs at the corresponding time-points.