Inhibition of Peroxisome Proliferator-Activated Receptor Gamma Prevents the Melanogenesis in Murine B16/F10 Melanoma Cells

The purpose of this study was to investigate if PPARγ plays a role in the melanogenesis. B16/F10 cells were divided into five groups: control, melanin stimulating hormone (α-MSH), α-MSH+retinol, α-MSH+GW9662 (PPARγ antagonist), and GW9662. Cells in the control group were cultured in the Dulbecco's modified Eagle's medium (DMEM) for 48 hrs. To initiate the melanogenesis, cells in all α-MSH groups were cultured in medium containing α-MSH (10 nM) for 48 hrs. Cells were treated simultaneously with retinol (5 μM) in the α-MSH+retinol group. Instead of retinol, GW9662 (10 μM) was cocultured in the α-MSH+GW9662 group. Cells in the final group were cultured in the DMEM with GW9662. All the analyses were carried out 48 hours after treatments. The α-MSH was able to increase cell number, melanin production, and the activity of tyrosinase, the limiting enzyme in melanogenesis. These α-MSH-induced changes were prevented either by retinol or by GW9662. Further analyses of the activities of antioxidant enzymes including glutathione, catalase, and the superoxide dismutase (SOD) showed that α-MSH treatment raised the activity of SOD which was dependent on PPARγ level. According to our results, the α-MSH-induced melanogenesis was PPARγ dependent, which also modulated the expression of SOD.