Fig. 6. Pharmacological evaluation of signaling pathways that mediate the IGF-I-dependent cell survival of Null+ cells. Null+ cells were placed in suspension and IGF-I (100 ng/ml), LY294002 (50 µM), or PD 98509 (50 µM) were added as indicated. The cells were then incubated at 37°C for 20 hours, lysed, and caspase 3 activity present in the lysates was measured.