PACAP and Forskolin Inhibit HH pathway activity in Primary Tumorspheres. (A) Expression of the HH target gene gli1 in 6-7 day old primary tumorspheres treated for 6 hours with either vehicle, 10 nM PACAP, 5 μM forskolin, or 1 μM SANT-1, determined by real time RT-PCR. Experiments were performed three times with at least n = 3 for each treatment (*P < 0.05, **P < 0.01). (B) RT-PCR analysis demonstrating gene expression of the PAC1 PACAP receptor in primary tumorspheres. Total brain (left lane) was used as a positive control. Negative controls (lower panel) utilized the same samples, but were not subjected to reverse transcriptase (RT).