ERK1/2, Src and PI3K regulation of Fra-1 expression in MM cell lines is tumor line-specific. A. RT-QPCR showing Src, ERK1/2, and PI3K-dependent decreases in Fra-1 in MM1, Src and ERK1/2-dependent decreases of Fra- 1 in MM2, and PI3K-dependent decreases in Fra- 1 in lines MM1, MM3 and MM4. B. Luciferase assays show PI3K-dependent Fra-1 promoter activation in MM3 cells. C. Western blot analysis of Fra-1 shows inhibition by the PI3K inhibitor, LY294002 at 20 μM. D. EMSA shows a dose dependent decrease in Fra-1 in the AP-1 complex after treatment of the MM3 line with the PI3K inhibitor, LY294002 at 10 and 20 μM * = P ≤ 0.05 in comparison to untreated control (0).