Figure 6.

A, B, and C. GaM inhibits cellular iron uptake and upregulates TfR1 expression in glioblastoma cells. A and B. ⁵⁵Fe up by U-87 MG (A) and D54 cells (B) was measured after cells had been incubated with ⁵⁵FeTf for 3 hours in the presence increasing concentrations of GaM. Values shown are means ± S.E. of ⁵⁵Fe uptake per 5 × 10⁵ cells. C. TfR1 expression in U-87 MG and D54 cells was measured by ¹²⁵I-Tf binding after a 24 h incubation of cells with 50 µM GaM. Values shown are means ± S.E. of specific ¹²⁵I-Tf bound per 10⁶ cells. Differences between control cells (*, no GaM) and GaM-treated D54 (**) and U87 (***) cells are highly significant (p= 0.002, n = 6, for D54, and p = 0.008, n = 3, for U87 cells). D, E, and F. Gallium-targeted iron proteins in glioblastoma stem cells (GSCs). D. Western blot showing ribonucleotide reductase M2 (RRM2) and H- and L-ferritin in GSCs-44, -3, and -22. E. TfR1 expression on GSC-22 and -33. E. TfR1-mediated internalization kinetics of cell surface TfR-bound ¹²⁵I-Tf. F. Inhibition of GSC cell growth by GaM. Cell proliferation was measured by MTT assay after a 120 h incubation of cells with GaM.