Figure 7. SF-3-026 and analogues inhibit Fos family proteins in melanoma cells.

(A) A375 cells expressing the AP-1 promoter construct were treated with 0–100 μM SF-3-026 analogues for 4 h followed by measurements of luciferase activity. Data were normalized to untreated A375 cells and represent the means ± S.D. from three independent experiments. (B) A375 cells treated for 1 h in the absence or presence of 10 μM U0126 or 50 μM SF-3-026 and analogues were immunoblotted for total c-Fos, FosB, FosB2 or Fra1. (C) Expression of total c-Fos, FosB, FosB2, Fra1, c-Myc or Egr1 from A375 cells treated in the absence or presence of U0126 or indicated concentrations of SF-3-030. Controls for inhibition by U0126 include phosphorylated Fra1 (pFra1 Ser²⁶⁵), pERK1/2 and pMEK1/2. (D) Expression of c-Jun or phosphorylated RSK1, ERK1/2 and MEK1/2 from A375 cells treated as in (B). α-tubulin expression was used for a loading control.