Fig. 3.

Retroviral transduction of B16F0 melanoma cells with a dominant negative isoform of PPARβ (PPARβDN) and siRNA transfection of A375 melanoma cells against PPARβ and subsequent treatment with a PPARβ agonist GW0742. Western blot for PPARβ from lysates of B16F0 cells without or with retroviral transduction of the PPARβDN (a). Note the increase in PPARβ in the transduced cells reflecting the level of the transduced dominant negative PPARβ expression. β-actin served as standard. Cells with or without retroviral transduction with the PPARβDN, were treated with the PPARβ agonist GW0742 for 24 h. Note that the strong growth inhibitory effect of GW0742 was completely abolished in the cells expressing the dominant negative isoform of PPARβ (n = 4, P < 0.001; b). Western blot from lysates of A375 cells transfected with siRNA constructs against human PPARβ (c). Silenced and control cells were treated with the PPARβ agonist GW0742 for 24 h. Silencing of PPARβ restores proliferation in the presence of different concentrations of the agonist (n = 8; d)