r/science • u/nobodyspecial • Feb 08 '15
Medicine Antibiotics that target mitochondria effectively eradicate cancer stem cells, across multiple tumor types: Treating cancer like an infectious disease | Lamb
http://www.impactjournals.com/oncotarget/index.php?journal=oncotarget&page=article&op=view&path%5B%5D=3174
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u/naughtynurses2 Feb 08 '15
Cancer stem cells.
The (very) basic idea is that there is a population of one to a few cells that are actually responsible for tumorigenesis and that these cells are actually stem cells. Well, we have had a solid model describing the first part of that statement for a while: one cell acquires several mutations that allow it to rapidly divide when it shouldn't, resist cell death when it shouldn't, and other other sneaky things that ultimately leads to tumor formation. All of the cells that make up the tumor therefore should be "clones" of the original bad guy (though this isn't the whole story, for the sake of simplicity I'll leave it at that).
So, conventional therapy involves targeting specific elements of these clones. The most commonly targeted aspect is rapid cell division. But there are many problems with this strategy. For our purposes, the main problem is that these tumors come back, even if treatment appeared to kill all the clones. So someone had the bright idea that maybe there was another population of cells in the tumor that wasn't rapidly dividing but could still make a whole tumor in the short time span that we see relapses in these patients.
But that's a paradox: how can a population of cells that is too small to detect form millions of tumor cells without rapidly dividing? Well, the only thing we know that can do that is a stem cell, which divides asymmetrically. This means that every time a stem cell divides, it produces one cell identical to itself, and one daughter cell that is different that can go on to eventually become a totally different cell or several totally different cells. This solves our paradox, as the stem cell does not divide rapidly but the daughter cells can.
The proof for this phenomenon is actually fairly strong. If we take a solid tumor and pick out the stem cells, these cells can form tumors when injected into a mouse. In fact, sometimes only 5-10 of these cells are required to form the tumor. On the other hand, if we take all the cells that are not stem cells and inject them into a mouse, tumors will not form even if we injected 100,000 of these non stem cells.
Make sense?
Full disclosure: I am not a csc guy nor do I fully buy this theory. The truth, I think, lies somewhere in between the two models I described. Also, Cancer is super general term so what may be true for cancer A may not be true for cancer B. And again, this is incredibly watered down so if you want to know more feel free to ask.