LDE225 is prepared for assay by serial dilution in DMSO and then added to empty assay plates. TM3Hh12 cells (TM3 cells containing Hh-responsive reporter gene construct pTA-8xGli-Luc) are cultured in F12 Ham's/DMEM (1:1) containing 5% horse serum, 2.5% fetal bovine serum (FBS), and 15 mM HEPES, pH 7.3. Cells are harvested by trypsin treatment, resuspended in F12 Ham's/DMEM (1:1) containing 5% horse serum and 15 mM HEPES, pH 7.3, added to assay plates, and incubated with LDE225 for approximately 30 min at 37 °C in 5% CO2. Then 1 nM or 25 nM Ag1.5 is added to assay plates and incubated at 37 °C in the presence of 5% CO2. After 48 hours, either Bright-Glo or MTS reagent is added to the assay plates and luminescence or absorbance at 492 nm is determined. IC50 values, defined as the inflection point of the logistic curve, are determined by nonlinear regression of the Gli-driven luciferase luminescence or absorbance signal from MTS assay vs log10 (concentration) of LDE225 using the R statistical software pack (Only for Reference)