Figure 3. STAT3 activation mediates the acquisition of the stemness phenotype in melanoma cells.

(A-B) 501mel cells were infected with increasing concentrations of lentivirus encoding either the parental empty vector (EV) or vectors encoding either a constitutive active form (STAT3C) or a dominant negative form (STAT3DN) of STAT3. Western blotting assays were performed with the indicated antibodies. (C) QRT-PCR experiments on RNAs prepared from 501mel cells left in control condition, exposed to IL6 (20 ng/ml) or transfected with a STAT3 siRNA cells and treated with IL6. Transcript levels are represented relative to those found in control cells as mean +SD. (D) Western blotting assays of 501mel cells transfected with a control (siC) or STAT3 siRNA left untreated or treated with recombinant IL6. (E) FACS analysis of MITF intensity of cells treated as in D. MITF intensity was plotted on abscissa and side scatter (SSC) on ordinates.