Primary Medulloblastoma Cells Form Tumorspheres and Exhibit Constitutive Hedgehog Pathway Activity. (A)Primary medulloblastoma cells from ptch1
+/- mice cultured in a serum-free environment formed tumorsphere-like aggregates within 24 hours, which became progressively larger at three and five days.(B and C) Quantitative real time RT-PCR analysis of gli1 gene expression in 6-7 day old tumorsphere cultures treated for 6 h with either the smoothened antagonist SANT-1 (1 μM) (B) or the smoothened agonist purmorphamine (3 μM) (C) Gene expression experiments were performed at least three times and with at least n = 3 samples for each treatment. (**P < 0.01).