How could cell apoptosis be used to treat disease?

Apoptosis is one of the fundamental processes that could be the key to treating certain diseases. If you know that cells can commit suicide, wouldn't there be a time when you'd want to trick cells into doing so, as in the case of cancer? And maybe there's a time when you'd take dying cells and turn off apoptosis, so that the cells could become immortal and you could revitalize damaged tissues, as in your knee cartilage.