APRIL stimulates PI3K and Akt activation. (A) Karpas cells were stimulated for the indicated times with APRIL, and phosphorylation of p85 and Akt (Ser473) was analyzed by Western blot. (B) Karpas cells were treated with 100 nM or 500 nM wortmamnin or 10 μM LY294002, and then stimulated with APRIL for 180 minutes and were analyzed for Akt phosphorylation. (C) Karpas cells transfected with control or TACI siRNA (100 nM) were stimulated with APRIL for indicated times and analyzed for Akt phosphorylation. (D) DHL-6 cells were transfected with control, TACI, or BCMA siRNA (100 nM) for 72 hours and subsequently induced with APRIL for the indicated times and analyzed for Akt phosphorylation. (E) Karpas cells were stimulated with APRIL or APRIL and heparin for the indicated time and analyzed for Akt phosphorylation. (F) CD19+ FL B cells were treated with APRIL for the indicated time and analyzed for p85 and Akt phosphorylation. Data from a representative patient are shown (n = 3). Densitometric values are listed below each blot.
