REQUIREMENT FOR THE CD95 RECEPTOR-LIGAND PATHWAY IN C-MYC-INDUCED APOPTOSIS

Induction of apoptosis by oncogenes like c-myc may be important in res training the emergence of neoplasia, However, the mechanism by which c -myc induces apoptosis is unknown. CD95 (also termed Fas or APO-I) is a cell surface transmembrane receptor of the tumor necrosis factor rec eptor family that activates an intrinsic apoptotic suicide program in cells upon binding either its ligand CD95L or antibody, c-myc-induced apoptosis was shown to require interaction on the cell surface between CD95 and its ligand. c-Myc acts downstream of the CD95 receptor by se nsitizing cells to the CD95 death signal. Moreover, IGF-I signaling an d Bcl-2 suppress c-myc-induced apoptosis by also acting downstream of CD95, These findings link two apoptotic pathways previously thought to be independent and establish the dependency of Myc on CD95 signaling for its killing activity.