Cell-death mechanisms in the IPLB-LdFB insect cell line: a nuclear located Bcl-2-like molecule as a possible controller of 2-deoxy-D-ribose-mediated DNA fragmentation

In the IPLB-LdFB insect cell line, oncosis and apoptosis are the two pre-mortal processes, whereas necrosis is the post-mortem condition. As found in mammals, adenosine triphosphate depletion of insect cells by oligomycin A induces oncosis. The apoptotic inducer 2-deoxy-D-ribose (dRib) provokes cell death through an intrinsic apoptotic pathway similar to that observed in mammalian models and results in oligonucleosomal DNA fragmentation. The addition to insect cells of an anti-Bcl-2 polyclonal antibody known to prevent dRib-mediated apoptosis abolishes DNA fragmentation, whereas cytochrome c release and the increase in a caspase 3-like activity are still detectable. These and previous findings suggest a double role for the Bcl-2-like molecule in IPLB-LdFB, i.e. the maintenance of mitochondrial integrity and the control of apoptotic machinery at the nuclear level.