Squetch: I saw your post while SI surfing and couldn't help but commenting. From someone who does biomedical research for a living, and this includes apoptosis assays, your question is more than you envisioned. In short, unless I'm completely misinterpreting Rob's post, the apoptosis statement doesn't make much sense.
Apoptosis is a somewhat bizarre although apparently quite common phenomenon. The suicide comparison is not too much of a stretch: a cell, after 'interpreting' what may be a constellation of signals from its environment, 'decides' it will activate aspects of its own machinery to destroy itself. Thus, by definition, if a cell 'undergoes apoptosis', it no longer 'is', it ceases to 'be', it is a dead cell (a weak attempt to paraphrase Monty Python). While Rob is correct that cancer cells, again by definition, have lost many of the normal constraints on proliferation and survival, and this may include a compromised ability to activate their apoptosis program, the fact remains that if cancer cells undergo apoptosis, they're history.
I'm also not aware how blocking DNA replication per se induces apoptosis but I'm all ears.
Two other things you should be aware of:
1) A hallmark of apoptosis is fragmented DNA: that is, as a result of a cell's suicide 'program', its DNA becomes 'scrambled' into smaller pieces. Researchers use this observation as a basis for detecting cells undergoing apoptosis (one common approach is the 'TUNEL' assay). An obvious question: can these assays be legitimately applied to cancer cells whose DNA tends to be scrambled even in the absence of apoptosis?
2) Beware that the word apoptosis is used quite loosely - its often applied to dying cells where apoptosis has not been rigorously confirmed (remember cells can just die by one of the old fashioned ways: murder, age, marriage). This may seem trivial but consider the implications: there's a huge difference between a cell being 'killed' by nasty influences, senescence, etc. and a cell being 'asked' to commit suicide. The former are passive and the latter is an active response with respect to the cell. The clinical implications are significant.
Y'all may want to check out the Univec thread.
Sorry to drivel on so long.
Best wishes,
Peter |
