Fig. 3.

Inhibition of FGFR signaling through bFGF depletion or ponatinib treatment decreases viability and induces apoptosis of cultured DIPG cells. (A) Depletion of bFGF for 72 hours significantly reduced cell viability of GBM-001 and DIPG-XIII, -XVII, and -XXV cells, while DIPG-007 cells showed reduced viability upon EGF depletion. PcGBM2 cells were not affected by EGF or bFGF depletion. (B) Ponatinib treatment for 50 hours induced apoptosis of DIPG-XVII and -XXV cells in a dose-dependent manner, while human astrocytes were affected at only the highest drug concentration. (C) Ponatinib treatment for 3 hours dose-dependently inhibited the phosphorylation of FGFR and bFGF-dependent downstream phosphorylation of ERK1/2 in DIPG-XVII and -XXV cells and, to a lesser extent, in human astrocytes. Bars represent mean ± SD of 3 independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001. GAPDH, glyceraldehyde 3-phosphate dehydrogenase; ns, not significant.