cAMP induces apoptotic cell death. (A) MOPC315 cells were treated for 24 h with 200 μM 8-CPT-cAMP or 50 μM forskolin. Overall cell death, changes in mitochondrial membrane potential and DNA breaks were assessed by PI staining, JC-1 staining, and TUNEL analysis, respectively. The results are presented as mean values+/-SEM of 3 experiments. (B) MOPC315 cells (left panel) and INA-6 cells (right panel) were treated with or without 50 μM forskolin. At the indicated time points, cells were collected and subjected to western blot analysis with antibodies recognizing full length and cleaved products of caspase 9, caspase 3 and PARP. One of 3 representative experiments is shown.