If there is an apoptosis shut-off mechanism of any kind, one could call it a null-apoptosis mechanism.
If this is possible, could there be a null-apoptosis inhibitor? Something that inhibits an apoptosis inhibitor?
Apoptosis is very tightly controlled for obvious reasons. Setting it off without proper control would result in the uncontrolled loss of cells. Apoptosis is one of the major pathways which are either mutated or shut-off in cancers, preventing the body from eliminating malingnant cells. These two papers are interesting in this context:
In this context it makes no sense to have a shut-off mechanism once the apoptosis cascade has started. It is only set off when there is a real reason (and is well controlled), so I don't think there a "null-apoptosis" mechanism. It would of course still be possible to artificially make substances, that inhibit parts of the activation cascade. But besides for apoptosis research I don't see any use for it. There is actually some research going on to find out how to activate apoptosis again in cancers.