PESTILENTIAL GARBAGE BAGS

Linda on Skye

As long ago as September of last year I introduced you to exosomes:

https://ljb-quiltcutie.blogspot.com/2018/09/exosomes-evolution-and-cancer.html

In that blog I related how recent research had found that exosomes, in addition to being molecular garbage bags, were – if emitted by cancer cells – also laden with a protein that could stifle the activity of immune cells, leaving them impotent as a weapon against cancer.

Only a few months later I “introduced” you to exosomes, apparently having forgotten all about my earlier post.  This blog described how people had perhaps discovered a way to prevent cancer cells from expelling their little garbage bags; I gloated that they might then die a painful death, of acute constipation!  This somewhat childish thought is elaborated in:

https://ljb-quiltcutie.blogspot.com/2019/03/molecular-garbage-bags.html

So now, Dr. Collins of the NIH continues the narrative:

https://directorsblog.nih.gov/2019/04/09/new-target-for-cancer-immunotherapy-exosomes/

It appears that work at U. Cal San Francisco (essentially a med school and lab complex, I believe) has verified that cancer-derived exosomes are laden with poison; specifically a protein named PDL-1.  PDL-1 binds with another protein, PD-1.  The problem is that some immune cells bristle with PD-1 receptors, and are summarily shut down by the binding of PDL-1.  Some types of immunotherapy are designed to prevent this sort of thing.

Well, it transpires that the molecular garbage bags we are considering go straight to the lymph nodes, a place where immune cells are perfected and readied for battle.  The PDL-1 carried in exosomes effectively shuts down the army before it is ready for battle.  Needed is a molecule that will effectively disable the bad guy – PDL-1.  They are working on it.  Many mice will die.

I admit to being slightly put out by Dr. Collins’ last paragraph, wherein he trumpets as evidence of rapid progress that 480 peer-reviewed papers on this subject have been published in the last few years.  Hell:  Progress is fixing cancer.  Some of those papers are valuable; specifically those that report findings essential to continued progress.  However, I’ll bet many of them are more of the “Hey, notice me, and give me a grant and/or a promotion” sort of thing.  We had a bunch of those in geology. Get back to your lab bench, guys!