FIGURE 6.

PI3K pathway activity in PTEN-deficient PCa cells is Ras-independent. LNCaP (left) or PC3 cells (right) plated into 24-well plates were treated with farnesylation inhibitor FTI-277 (20 or 40 μm; prepared in serum-free medium) for 2 days, and non-drug-treated wells were serum-starved for the same duration. At the end of FTI-277 treatment, cells were either treated with LY294002 (20 μm, 2 h) or stimulated with EGF (20 ng/ml, 5 min). Whole cell lysates (10 μg) were analyzed by immunoblotting for pAkt, pPRAS40, total Akt, ERK1/2, phospho-ERK1/2, Ras, or tubulin. Upper and lower bands corresponding to Ras and farnesylated Ras (fRas) are indicated.