Downregulation of caspase-2 does not affect caspase-3-like activity. A, PC12 cells were deprived of serum in the presence or absence of antisense Nedd-2 (400 nm) or 100 ng/ml NGF. At 6 hr after serum deprivation, cell lysates were assayed for the presence of DEVD-cleaving activity, as described in Materials and Methods. Results are expressed as mean ± SEM of three samples. B, Replicate cultures from the same set of cells as in A were assessed for survival at 24 hr after NGF deprivation by counting the number of intact nuclei, as described in Materials and Methods. Results are expressed as mean ± SEM of three samples. C, Neuronally differentiated PC12 cells were deprived of NGF in the presence or absence of antisense Nedd-2 (400 nm) or 100 ng/ml NGF. At 24 hr after NGF deprivation, cell lysates were generated and tested for DEVD-cleaving activity, as described in Materials and Methods. Results are expressed as mean ± SEM of three samples. D, Replicate cultures from the same set of cells as in C were assessed for survival at 48 hr after NGF deprivation by counting the number of intact nuclei, as described in Materials and Methods. Results are expressed as mean ± SEM of three samples.