Figure 4.

Reversal of α5-mediated cell protection by PI-3-kinase inhibition. LY294002 was added to culture medium at the beginning of serum deprivation. The vehicle, DMSO, was maintained at <0.1%. (A) Reversal of α5-mediated antiapoptotic effects in α5-c10 cells by PI-3-kinase inhibition. Cells were serum starved for 72 h without (upper panels) or with (lower panels) 20 μM LY294002 before TUNEL assay. (B) Reversal of antiapoptosis effects in α5/1-c3 cells by PI-3-kinase inhibition. α5/1-c3 cells were serum starved for 20 h (left histograms) or 72 h (right histograms) without (upper panels) or with (lower panels) 20 μM LY294002 before TUNEL assay. Data shown are representative of at least two independent experiments. (C) Dose-response effect of LY294002 on apoptosis in serum-starved RIE1 cells. Open bars, WT cells; closed bars, α5-c10 cells; cross-hatched bars, α5/1-c3 cells. Data shown are representative of at least two independent experiments. (D) Serum deprivation–mediated apoptosis in additional cell lines. α2-c5, α5/1-c16, and α5-P2 cells were maintained in the presence of serum (+), or were serum starved (−) for 72 h, in the absence or presence of LY294002 (20 μM) before TUNEL assay. Means and SEs are shown.