Calcium overload is essential for the acceleration of staurosporine-induced cell death following neuronal differentiation in PC12 cells.

Differentiation of neuronal cells has been shown to accelerate stress-induced cell death, but the underlying mechanisms are not completely understood. Here, we find that early and sustained increase in cytosolic ([Ca2(+)]c) and mitochondrial Ca2(+) levels ([Ca2(+)]m) is essential for the increased sensitivity to staurosporine- induced cell death following neuronal differentiation in PC12 cells. Consistently, pretreatment of differentiated PC12 cells with the intracellular Ca2(+)-chelator EGTA-AM diminished staurosporine-induced PARP cleavage and cell death. Furthermore, Ca2(+) overload and enhanced vulnerability to staurosporine in differentiated cells were prevented by Bcl-XL overexpression. Our data reveal a new regulatory role for differentiation-dependent alteration of Ca2(+) signaling in cell death in response to staurosporine.