
Find and Replace: DNA Editing Tool Shows Gene Therapy Promise - sciadvance
https://directorsblog.nih.gov/2017/01/24/find-and-replace-dna-editing-tool-shows-gene-therapy-promise/
======
xiphias
It would be interesting to know how the scaling-up procedure works? Is it
similar to scaling up and productionizing a software system?

Anyways, I guess the only question is how much time it will take to have mass-
scale gene editing on people.

~~~
nonbel
If you are imagining having something injected into you and your cells being
"edited" in situ, I doubt it can happen with this tech. The process is very
toxic to cells in every paper that reports that aspect. You will only see them
remove the cells, "edit" them in a dish, then inject them back in.

I even suspect a major portion of the "editing" is not editing at all, but
rather selecting for the small number of pre-existing cells that are mutants
at any site. This works because the mutants are "immune" due to lacking the
recognition sequence.

Then again, I haven't read a paper on it in awhile now (and the ones posted
here seem to be mostly editorials nowadays), so maybe they figured something
out.

~~~
dekhn
"The process is very toxic to cells...." you mean like chemotherapy?

~~~
nonbel
Yes, the way CRISPR/Cas9 works, the DNA must be damaged.

However, chemotherapy is not very selective about which cells it damages.
Here, the DNA is much more difficult to damage if it is already missing the
exact sequence being targeted for "editing", so the targeted cells will die
while the mutants divide to take their place.

If I thought specific somatic mutations were good drug targets for cancer, I
would be more enthusiastic about CRISPR/Cas9 as a less toxic chemotherapy than
a gene-editing therapy.

------
pogba101
I really wish I could get the take of an impartial scientist on this. How much
is hype vs reality?

~~~
danieltillett
I am a scientist and I am impartial if that is good enough :)

The major problem is the same as it has been for the last 30 years - delivery.
You can make the most amazing molecular machinery for modifying genes, but if
you can't get it into a very high percentage of adult cells then it is useless
for most treatment purposes. We still don't have any good delivery systems
that work on all cell types and doesn't come with the very real risk of death
via immune hyper reaction.

~~~
lisivka
IMHO, in some cases, cells can be converted into stem cells, repaired in lab
conditions, and then delivered back into damaged organ or area.

~~~
danieltillett
Yes some haematological diseases can be treated this way, but not much else.
We really need much better delivery systems that work in all tissue types.

------
tabeth
Is it a false dichotomy for me to say: "we can't even fix the economy; I'm
skeptical to think we're going to do any serious modifications to our DNA with
positive, well directed results that are absent in shocking negative side
effects."?

Disclaimer: I know more about the economy to DNA, which is to say, still not
very much.

~~~
TeMPOraL
I think economy is harder than biology, for the same reason it's harder than
physics - because economy involves thinking actors with conflicting goals,
many of whom will happily use their cognitive powers to oppose your fixes to
the economy. Biology may be complex, but it's not made of actors smarter than
you who will work against you, sometimes just out of spite.

