Tailor-Made Cancer Drugs

pmineiro writes "A researcher at Washington University in St. Louis has developed a method for delivering an inactive drug complex into the body, which is only activated by certain messenger RNA sequences. This allows a drug to be selectively activated only in certain cellular contexts, e.g., cancer or HIV infection."

Comments

This is big

[Henry V .009]

Very cool. The very generalness and nature of this approach makes me want to categorize this as nano-machine rather than new drug.

Scary

[Rick the Red]

Maybe I've got an evil side that sees the bad in things, but this reminds me of several stories where individuals are targeted based on their DNA. Seems like a small step from this to a poison that only activates in people with a specific DNA sequence...

Have you ever taken a science class before?

[helix400]

In the presence of cosmic rays and background radiation, to say nothing of the computer monitors, cellular phones, and irradicated beef that we surround ourselves with every day, these genetic superdrugs could easily mutate. In their new forms, they'd be essentially unstoppable. One stray gramma ray could spell the end of humanity.

You would make a great B-Movie script writer.
Unfortunately, virtually nothing you said can be backed up scientifically. Your flaws are these:

1) How is this drug going to spread? Drugs are molecules, not viruses or bacteria. The drug will simply stay inside the person they give it to.
2) If this drug *could* spread, how is it going to reproduce itself? Luckily, drugs dont self-divide or mate to reproduce.
3) Irratiated beef is NOT radioactive, neither are cell phones. Therefore, harmless beef and cell phones will not alter a drug. (Techinically cell phones give off radiation in the form of radio waves, but visible light gives off far more energetic radiation than a cell phone does.)
4) Gamma rays, computer monitors, and background radiation could only affect a change in the drug in miniscule amounts. Generally, if one drug molecule was hit by a stray gamma ray, it would change one molecular bond, and perhaps mess up the configuration of the molecule. At absolute worst, a single change alter the drug in such a way that it would kill the person using the drug, but that's *extremely* unlikely.

Personally, I've read the article, and feel this is a pretty good idea. He uses already approved FDA drugs, and just does a better job targeting them.

---
Abortions for some, miniature American flags for others! - Kodos

Re:not such a good idea...

[NickFusion]

Think of it as cryptology. You have a PGP encoded message (drug) that can only be unlocked by the appropriate key (rna trigger).

Your cosmic ray scrambles the code, and the odds of it binding to some random spot is low. How low? That would be good to know.

But the whole dru/key pairing is artificial, it does not reproduce, so even if the one molecule of the batch they give you for disease X gets scrambled, you are the only one who has to worry, and in fact, it is only one healthy cell that has to worry, because once that molecule delivers its payload, no more payload.

So, in this case, sleep well, for humaity is safe.

You may want to avoid Porktatos, the latest GMO snack, however...};^)

Re:not such a good idea...

[idiot900]

> In the presence of cosmic rays and background
> radiation, to say nothing of the computer
> monitors, cellular phones, and irradicated beef
> that we surround ourselves with every day, these
> genetic superdrugs could easily mutate. In their
> new forms, they'd be essentially unstoppable.
> One stray gramma ray could spell the end of
> humanity.

<SARCASM>So, good thing you actually read the article, and have a solid grasp of the relevant biology.</SARCASM>

Mutations in the prodrug and catalyst would most likely decrease their binding affinity for their target sequence, and likely mRNA sequence in general. Thus, the drug would be *less* likely to be activated.

The idea that the "genetic superdrugs" would easily mutate and "spell the end of humanity" is ludicrous. For this to happen, they would need some way to reproduce themselves, which they don't. If they did, they would be analogous to virii. While virii are often pathogenic, they haven't destroyed humanity as of yet.

(By the way, I'm amused by people who talk about "what Nature intended". Did you have a nice long chat with Nature about this stuff? Did Nature give you an itemized list of things Nature intended? If so, the next time you and Nature do lunch, I'd like to tag along.)

Re:not such a good idea...

[NerdGirl82]

As I see it, the whole thing won't work on a broad scale anyway without a great deal of rather expensive personalization of the drugs.

Because of the redundancies of the genetic code, even highly conserved nucleic acid sequences likely differ significantly between individuals (don't forget also that a single gene mutates on average every million replications, each person has trillions of cells, many of which live a short period, then replicate themselves and their entire genome).

Secondly, cancer cells are highly mutated from their original form, and barely hang on to life as they replicate as fast as they can. They are probably not very representative of the person that they originate in.

The result is that the drugs will likely need to be adapted to work in every patient specifically, will need to be synthesized, purified, possibly isolated from their isomers, etc.... It's not that this isn't feasible, but I don't see it as being able to be effectively provided as of yet.