Okay!
I left off last time saying that we have
two big issues to address with regard to hypoxia as a cause or exacerbating
factor in cancer:
- What causes tissue to become hypoxic?
- Is there a role for hyperbaric oxygen therapy in fighting cancer?
Let’s tackle them in order.
To be honest with you, I still don’t
know which comes first: low oxygen, or mitochondrial dysfunction. The fact is,
even when there’s plenty of oxygen available,
if the mitochondria are malfunctioning, they can’t use it. But what if what’s causing
the mitochondria to malfunction is insufficient oxygen? (I told you last time this stuff is complicated!)
It almost doesn’t matter, right? The bottom line is, whether the tissue is hypoxic or
not, the mitochondria are not using
whatever oxygen might be present. (Well, they’re using some of it. Remember, kids, when it comes to biology and
biochemistry, there are very rarely any absolutes, yes or no, on or off. Things aren't binary, but rather, there's a balancing act.
Even cancer cells have some
mitochondria that are okay; it’s just that the majority of them are messed up.)
I just have a hard time wrapping my head
around it all. Think about angiogenesis: the creation of blood vessels
specifically so that the cancerous tissue ensures it has a steady supply of
fuel and nutrients. But what does blood carry besides fuel and nutrients? OXYGEN. So you would think that
angiogenesis would give cancer cells more
oxygen, not less. So going one step further, this being the case, it seems like
the mitochondrial dysfunction comes first, because theoretically, there should
be sufficient oxygen delivery to the cancer cells, what with all those blood
vessels they created for their own nefarious purposes. So there is sufficient oxygen (“normoxia”), yet
we have hypoxia-inducible factors out the yin-yang upregulating all sorts of
nasty pathways and reactions in these cells to keep themselves alive because
they think they’re hypoxic. And the
reason they think they’re hypoxic is
because the mitochondria aren’t using
the oxygen. (That’s my logic, anyway. I told you there was going to be a lot of
wild speculation here, and so it begins.)
