Bax‐dependent apoptosis induced by ceramide in HL‐60 cells

Ceramide is an important lipid messenger involved in mediating a variety of cell functions including apoptosis. In this study, we show that antisense bax inhibits cytochrome c release, poly(ADP‐ribose)polymerase cleavage and cell death induced by ceramide in HL‐60 cells. In addition, ceramide induces translocation of Bax to mitochondria. The addition of the broad spectrum caspase inhibitor zVAD‐fmk prevented ceramide‐induced apoptotic cell death but did not inhibit translocation of Bax and mitochondrial cytochrome c release. Furthermore, ceramide inhibits the expression of the antiapoptotic protein Bcl‐xL with an increase in the ratio of Bax to Bcl‐xL. These data provide direct evidence that Bax plays an important role in regulating ceramide‐induced apoptosis.