Effect of GSL on Gli-mediated transcriptional activity in human pancreatic cancer PANC-1 cells. PANC-1-Gli-luc cells were seeded onto a 96-well plate and treated with various concentrations (0, 1, 5, 10 and 20 µM) of GSL. GANT61 (30 µM) was used as the positive control. Luciferase activity was measured following 20 h using a microplate luminometer. The ratio of luciferase reporter activity of the GSL-treated cells/vehicle-treated cells was calculated as the inhibitory effect on Gli-mediated transcriptional activity. *P<0.05 vs. control. GSL, germacranolide sesquiterpene lactone; Gli, glioma-associated oncogene.