Figure 2.

C-MYC depletion induces senescence-associated β-galactosidase (SA-β-Gal) activity in melanoma cells. (a) Normal melanocytes were infected with control lentiviral vector (V) or vectors expressing BRAF^V600E or NRAS^Q61R cDNAs (indicated at the top of the panel). Cells were fixed and stained for SA-β-Gal activity, according to Materials and methods, after 18 days (control and BRAF^V600E-infected melanocytes) or after 6 days (NRAS^Q61R-infected melanocytes). Numbers below the panel indicate percent of SA-β-Gal-positive cells detected in each population (100 cells were counted in each of the duplicate plates). (b) Melanoma cells designated on the left from each panel with the number assigned in Figure 1b were infected with control shRNA (CL) or M1- or M2-shRNAs. Cells were fixed and stained for SA-β-Gal activity, according to Materials and methods 6 days after infection. Numbers below the panels indicate percent of SA-β-Gal-positive cells detected in each population (100 cells were counted in each of the duplicate plates).