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Cure for Cancer?
Ensign Regis writes "MIT's Technology Review is reporting that an Israeli institute has developed "molecular-sized" computers that can detect and eradicate cancer cells. Right now, it only works in test tubes, but it may soon be developed for humans."
While it is great that this may one day cure cancer in people, I think it's fantastic that in the mean time we can keep our test-tubes healthy.
Paul Lenhart writes words!
Clinical research is caught between a rock and a hard place. If a therapy turns out to be dangerous in human trials, the researchers are heartless murderers; if a therapy isn't instantly available to everyone whom it might benefit, the researchers are heartless murderers. The compromise we have works that way for a reason.
By the way, has anyone read the Nature article and understood what this thing does? It looks like incredibly clever work, but it's presented with so much hype (the repeated references to "drug release" instead of whatever actually happens -- cleavage of an oligo, transcription?) that it's hard to make sense of. Maybe the third time this story is posted here, it'll be clearer.
What I'm listening to now on Pandora...
Weizmann Institute of Science disovers Cure for Cancer.
+1 happy citizen in each Israeli town.
My center is giving way, my right is in retreat; situation excellent. I shall attack.
I think that's pretty much his point.
...F'ing semantics.
"I'm going to die soon. You have a treatment that needs testing. F*** it, if I'm going to die anyway use my as a test subject so hopefully others can benefit from what you learn."
"Oh no! We can't do that. It has to be approved for human trials first! We wouldn't want to harm you..."
"I'm going to die anyway! How much could you possibly harm me?"
"It doesn't matter, it would be unethical."
"But thousands of people die of this disease every year. Is it perfectly ethical to let this potential treatment sit on a shelf for ten years before you even start testing it?"
"Of course! We wouldn't want to harm anybody. It doesn't matter how many people die while we drag our feet through red tape. As long as we haven't touched them, we aren't responsible for their deaths!"
=Smidge=
I don't have access to the paper itself (that requires a subscription), but Nature news has a slightly more informative article.
It looks to me like the computer part is single-stranded DNA that base pairs with the mRNA for certain cancer genes. Presumably when a high enough level of these mRNAs is sensed, another DNA molecule is released. This one is supposed to prevent expression of the cancer genes... I'm guessing it is an antisense molecule, but the news article doesn't say. The news article also has no detail on how the drug is released. My guess is its a cleavage event. DNA enzymes capable of self-cleavage have been created in the past.
To me, it looks like the advance here is the "computer" part, not the drug part. And even that is still very much in the pre-clinical realm. The Nature news article says that it only works under particular salt conditions. Also, they haven't looked at how the immune system would respond to these computers. The immune system does respond to some DNA molecules, so that is definitely a concern.
Its interesting work, though. I may have to head over to my local university library and get my hands on the actual paper.
But in practice, doctors and researchers _are_ expected to not actively kill people and subjects _wouldn't_ take full responsibility for the consequences of any crazy-ass scheme they volunteered for. Therefore, we don't have a system where people read about pre-pre-pre-clinical research like this, show up in the lab and have a grad student start injecting god-knows-what into them.
What I'm listening to now on Pandora...
I went and found someone with a subscription to Nature, and got a hold of the paper. Its actually a short Letter. They don't spend much time on the chemistry, being more interested in the logic. However, they do put their methods in the supplementary materials. They are still a bit vague for my taste, but maybe I've just been out of the wetlab for too long! So take the following with a grain of salt... I'm not really sure I understand their chemistry yet, and I had to stop trying and get back to my real work. (:
It looks to me like their recognition molecules are engineered to include a FokI (restriction enzyme) recognition site. So when the recognition molecule binds to the diagnosis molecule, a dsDNA is created with the FokI site. These causes a portion of the diagnosis molecule to be cleaved.
This can happen with recognition molecules each of the four mRNAs considered to be diagnostic of the type of cancer they are "curing" (prostate cancer). If all four positive recognition molecules are processed, enough DNA is chewed away by FokI to release the drug, which is an antisense ssDNA for MDM2 or another previously studied antisense drug.
They have opposite logic in DNA attached to a drug suppressor (presumably the anti-antisense?), providing additional diagnostic control.
For effective drug administration you need the diagnostic molecule to release its drug, and the drug suppressor molecule NOT to release the suppresor.
What I have yet to figure out is how the recognition molecules are generated when the correct mRNA levels are sensed. The diagnostic state for prostate cancer has two genes downregulated and two genes upregulated. So a positive diagnosis is supposed to occur when the concentration of the first two genes is zero and the concentration of the other two genes is non-zero. But as I said, I haven't yet understood how these inputs are turned into the correct recognition molecules.
All of this work is being done with synthetic DNA and RNA in a test tube.
Seriously, I don't. Give me a test tube full of cancerous cells and I'll give you a million ways to kill them.
Killing cancer cells in a test tube: Easy.
Killing 100% of all cancer cells in a living human body whilst leaving the rest of the cells unharmed with no life critical side effects: Near impossible.
It's a long, long way to go yet.
I am government man, come from the government. The government has sent me. -- G.I.R.