Effect of GSL on Gli1 and cyclin D1 protein levels in human pancreatic cancer cells. Cells were treated with GSL at the indicated concentrations for 20 h. Cell lysates were prepared, and the Gli1, cyclin D1 and β-actin protein levels were determined by western blotting. Images are representative of three independent experiments with similar results. GSL, germacranolide sesquiterpene lactone; Gli1, glioma-associated oncogene homolog 1; p-, phospho.