SF-induced HPC line cellular viability and proliferation requires PI-3 kinase activity in vivo. (A) HPCs were cultured in the presence of SF without inhibitors (♦), SF with 20 μM LY294002 (▴), or SF with PD98059 (▪). (B) HPCs were cultured in the presence of SF without inhibitors (♦), SF with 20 μM LY294002 (▴), or SF with PD98059 (▪). Cells were stained with 0.4% trypan blue (Gibco) and examined under visible light for the ability to exclude trypan blue. Each time point represents 2 independent experiments performed in triplicate (SEM).