The hedgehog pathway is functional in T-ALL cell lines. (A) Relative proliferation of ALL-SIL, MOLT4 (hedgehog inhibitor sensitive cell lines) and P12-Ichikawa, SUPT1 (hedgehog inhibitor insensitive cell lines) after knockdown by siRNA targeting SMO, GLI1, and SUFU messenger RNA. (B) Stimulation of ALL-SIL and MOLT4 cells with hedgehog ligands results in upregulation of the GLI1 target genes BCL2 and GLI1. (C-D) Stimulation of ALL-SIL with hedgehog ligand results in GLI1 nuclear relocation. GLI1 (red) localization in ALL-SIL cells before stimulation (T0) and 30 minutes after stimulation with the IHH ligand (C). Statistical representation of GLI1 localization as ratio between nucleus and cytoplasm (D). **P < .01; ***P < .001. Error bars indicate SEM.