Transcripts
DR. LINGWOOD:
This slide is a simplistic view
of how the toxin gets into cells. It originally
was thought, that the "B" subunit was just the
means to get the "A" subunit into the cell.
Yes?
SPEAKER:
Quick question, what is apoptosis; what does that mean?
DR. LINGWOOD:
What is
apoptosis? There's a whole science. I think
there's probably been a thousand papers published
on this. It's the big area in terms of cancer
and cell regulation. Apoptosis (or programmed
cell death) is a mechanism by which cells die
but without disturbing homeostasis.
When a cell is killed, for
example by a toxin, its contents are released,
and that is a traumatic situation for an
organism as it gets all this junk and causes
inflammation.
Apoptosis is a mechanism by
which an organism can get rid of a cell without
undergoing that trauma, a quiet kind of death.
It's a genetic program, which
undergoes a series of steps which are not
completely worked out by which initially a
nuclear envelope is broken down. The DNA gets
clipped up and is impaired.
Apoptosis is a kind of cell
turnover. And why it's so important is that
cancer cells are oftentimes defective in their
mechanism of apoptosis. If you could induce
cancer cells to correct their apoptotic
regulation, they wouldn't grow uncontrollably.
And most anticancer agents are actually high inducers
for apoptosis.
All right. So verotoxin/Gb3
binding targets both the "A" and "B" subunit to
go into the cells, and actually, we don't see
that the subunits separate.
