a. A375 human melanoma cells were infected with control (GFP) or GFP/p16-expressing lentivirus, then 6 d later lysates were subjected to Western blotting. b. Cells in a. analyzed for mitochondrial superoxide by flow cytometry. Error bars indicate SEM from duplicate determinations, *P < .001. c. Maximal respiration of cells in a.. Error bars indicate SEM from 9 determinations, *P = .04. d. A375 cells were infected with control (GFP) or GFP/p16-expressing lentivirus, then 48 h later were placed in migration assay, and migrating cells counted at 24 h. Error bars indicate SEM from triplicate determinations, *P < .001. e. Human melanocytes were infected with control (GFP) or GFP/p16-expressing lentivirus, then 6 d later lysates were subjected to Western blotting. f. Cells in e. analyzed for mitochondrial superoxide by flow cytometry. Error bars indicate SEM from duplicate determinations, *P < .001. g. Maximal respiration of cells in e.. Error bars indicate SEM from 9 determinations, *P < .001. h. Melanocytes were infected with control (GFP) or GFP/p16-expressing lentivirus, then 48 h later were placed in migration assay and migrating cells counted at 48 h. Error bars indicate SEM from triplicate determinations, *P = .003.