Slashdot Mirror
Combining Nanotech and Radiology
Twilight1 writes "According to this article at CNN, researchers are testing a microscopic "smart bomb" to target, attack, and kill cancer cells. It's quite fascinating that they are using radioactive by-products from the production of nuclear power and weapons as the effective payload."
I saw this last night on @Discovery.ca, and it reminded me when I saw this on some TV show, this must of been my grade 6 (7 years ago).
I'm glad to see they finally have this in practical use.
I'm a big retard who forgot to log out of Slashdot on Mike's computer! LOOK AT ME.
Perhaps a biologist can answer a question I've had about this, which is also related I suppose to Chemotherapy.
What is the difference between a cancer cell and a "normal" cell? Why would radiation therapy tend to kill cancer cells faster than normal cells? The article mentions that they are concerned that normal cells might be affected, but they don't explain why it would favor cancer cells in the first place.
Sometimes it's best to just let stupid people be stupid.
i wonder if the fact the mice were glowing made sleep difficult?
I think that this is a very interesting venue in the treatment of cancer. Even though the radioactive atom "eventually becomes harmless and remains in the body," I still think it highly possible that this treatment may be nullified by the radiation emitted by the nanogenerators. Hopefully this is not the case, and we will have found an effective and non-harmful (minimally so, at least) treatment for cancer.
I've been wondering this for some time. Cancer cells are cells which multiply indefinatly, as opposed to normal cells, which only multiply for a specified amoutn of time, and then die off (with the exception of stem cells). Correct? Ok. Well' if I am right so far, can someone tell me why more research isn't going into controlling cancer, rather than destroying it? Like, I would think, if you could start and stop the cancer effect at will, you could live forever. Am I totally off base?
They are held together in the same way that magnets can stick together -- the isotope has a positive charge and the molecular cage has a negative charge.
Magnets do not stick together because one has a positive charge and the other has a negative charge. I learned this in third grade science.
There are 10 types of people in this world, those who can count in binary and those who can't.
There are two reasons this particular therapy favors cancer cells over "normal cells"
First: the caged actinium-225 is attached to a monoclonal antibody. The antibody (or, in their case, 4 antibodies) binds very nicely to a specific receptor/molecule. Ideally, this receptor/molecule is ONLY found on cancer cells, and not on healthy cells. In practice, this isn't ever the case - but there are a number of receptors which are more prevalent on cancer cells than normal cells. There are a couple of FDA approved anti-cancer treatments which make use of monoclonal antibodies (such as Mylotarg and Herceptin).
Second: Why does radiation kill cancer cells faster than normal cells? Well - 'radiation' does bad things to DNA - it can cause strand breaks, or base-pair dimer formation. These sorts of things happen all the time in cells, and they have a number of repair mechanisms to take care of just these sorts of problems, if they have enough time (and the damage isn't too severe). In cancer, cells are typically dividing as fast as they possibly can, since the normal regulatory checkpoints which govern cell division are often missing or damaged. Often, cancerous cells will even have problems with their DNA repair mechanisms. So - the repair mechanisms don't have time to fix the damage before the cell replicates its DNA or divides. The result of faulty or incomplete DNA synthesis is unpredictable, but often bad - in other words, the cell dies.
By the way, the journal article can be found here.
Actually, one of the greatest benefits of radioimmunotherapy compared to conventional radiation therapy is that it's much better at treating metastatic cancers. Since the radiation is attached to antibodies, it will circulate through the blood and attach to cancerous cells wherever they happen to be. That makes it a great technique for treating cancer that's spread beyond its initial tumor. A slight modification to the technique can also be used for diagnosis; they use a different isotope, one that emits gama-rays rather than alphas, and then use a gama-ray sensitive camera to image where the isotopes wind up. That lets them find out where the cancer has spread.
There's no point in questioning authority if you aren't going to listen to the answers.
Is it just me, or are these biologists a terribly orderly bunch?
Alpha emitters are great for this kind of work, because alpha particles have a high interaction cross section once they're inside the body. That concentrates their damage in a small space. (You can handle blocks of alpha-decay material without hazard, because the alpha particles plough into your epidermis and stop there, wreaking terrible damage on ... tissue that's already dead.)
I bopped on over to one of the online charts of the nuclides to check out the decay chain of Ac-225. Indeed, the next two daughters are alpha-emitters, but the first one, Fr-221, has a 5-minute half-life. That ought to give it plenty of time to get ducted around into your bloodstream and into the rest of your body before emitting the next two alphas and a couple of beta particles, eventually transmuting to stable Bismuth.
So the developers aren't being quite candid when they say that the daugter alpha particles could inflict additional damage on the tumor. Sure, they could -- but (with the antibody bonds long since broken by the recoil from the initial decay) that atom could end up anywhere in your body before decaying again.
This stuff is interesting -- I used to make radioactive saline at the Reed Reactor Facility for medical uses, so I poked around the chart of the nuclides to see how one would make Ac-225. Ideally, you want to start with a nice, stable (or at least long-lived) element, kick a neutron into it (by lowering the ore into a nuclear reactor), and let it turn into what you want via a series of rapid decays. (That's one way to make the Americium 241 in smoke detectors; I'll leave the source element as an exercise for the reader). But Ac-225 doesn't seem to have any such nice precursor decay paths with short half-lives. The half-life is short enough that you wouldn't want to get it from spent fuel (too `hot' until after the Ac-225 is gone!), so I'm not entirely sure how you'd make it.
Just as an aside:
Chemotherapeutics (at least, some anthracyclines) not only muck around with DNA, but can lead to free radical generation & can damage cellular membrane components.
They're nasty, nasty molecules.
I work at the National Cancer Institute and figured I'd give my personal scientific view (not official, since I'd get flayed for doing that).
While the research *is* interesting there are a lot of caveats. The article specified that this technique has been successful in treating a broad range of cancers. In culture. This means there's cells in a flask with medium and they add the agent to the medium. This means the cancers are definitely coming in contact. In a human system, this may not be the case. An intravenous injection may not service tumors embedded in tissues. Especially brain tumors because of the blood-brain barrier.
Another caveat. Nearly every system of targetted therapeutics involving antibodies has failed in humans, despite any remarkable results in mice. Several other wildly successful therapeutics in mice (angiogenesis inhibitors for example) are only modestly successful in humans.
Models, be they mouse or cell culture, do not carry over terrifically well to 'in the wild' cancers in humans. Entirely possible that these treatments will have some benefit for certain cases. On the whole, this isn't the "smart bomb" or "cure for cancer" the media portrays. Unfortunately, the AP doesn't report the caveats. Also, as of yesterday, I wasn't able to find any reference to this study in medical literature. I suspect that the moment the journal it was submitted to accepted the paper, a publicist was on the phone with the press. Accordingly, the media story is in the hands of the public before the peer reviewed article is.
Just another case of wait and see. I hope for the best, but don't expect it (sorry guys).
Ciao, C.Sc.
"The ring holds the atom in the center like a hula hoop containing a basketball," said Scheinberg.
Have you ever seen Micheal Jordan do that trick were he spins a basketball around inside of a hula hoop?
No? That's because it's damn hard!
Actually, this sounds like a nifty application of technology. Even if the device has targetting capabilities to rival the US missles that blew up the hospitals in Afghanistan (wink), it'll probably do less damage to normal cells than chemo.
It seems like a lot of the harmful side effects come from using actinium-225, which self-decays, not necessarily waiting until it has accumulated in it's targeted host. I wonder if they could use boron instead, which is fairly inert, and a beam of neutrons to accomplish the same task.
Back in my college co-op days, I worked at the Idaho National Engineering Laboratory in Reactor Design. Down the hall they were doing brain tumor studies on rats treated with a technique called BNCT: Boron Neutron Capture Therapy. The theory was to inject a water soluble boron compound into the body. Water soluble molecules do not pass well through the "blood-brain barrier", therefore, will not easily pass into healthy nerve cells. They do, however, accumulate in cancer tissues. Boron is nice because it is fairly inert until it interacts with neutrons and breaks down into alpha particles and non-threatening elements. So the theory was that the Boron would accumulate in the tumors and they could then bombard the tumor with neutrons, producing an explosion of alpha radiation... no more tumor. I didn't work on this project, and I'm not sure what became of it.... I think this technique may be used in other countries.
I think the nice thing about the current technique is the ability to target specific proteins. I wonder if a boron/neutron might have an additional advantage - unlike actinium which would decay over time (like the oven on "warm", the boron approach would be more immediate. Think "broil".
this may actually be a cure. A CURE for cancer
Good. Now, the next time some "basic research" project like the SSC or a NASA planetary probe gets government funding, people won't be able to ask why their tax dollars are being "wasted on this %^#@$ instead of trying to find a cure for cancer" (and advances in genetically-modified foods should be able to get rid of the "... ending world hunger" one before too long too).
[Yeah I know, but my Karma's at 50 anyway, so go ahead and take your best shot...]
[Also, I remember reading about monoclonal antibodies in Discover or a similar publication back in the '80s. It doesn't appear to have been the miracle cure they thought it would be. Hope they have better luck making the jump from mouse to human this time]
You idiots.
You totally missed the point.
The element in use is actinium. The particular isotope decays rapidly, and leaves no left over damaging radiation, so this whole 'polluting our bodies with nuclear waste' crap is out of line.
As far as it not know which cells are the right cells, wrong again. Ever heard of monoclonal antibodies? Did you read the article and do a little research before you responded? no. So shut the hell up.
The buckyball-like cage prevents radiation from harming cells that don't exactly match the monoclonal attachment, i.e. normal cells aren't targeted.
I do not respond to cowards. Especially anonymous ones.
It think it is slightly premature to hail this as the cure for cancer. The problem is without a subscrition we can't even get to the Science magazine website. I'd love to peruse the article but i think it needs registration, and the free version seems to only give abstracts. We don't have proper figures on their tests so there's no way we can individually verify what the article is saying.
The treatment may work on mice but its no guarantee it will work on humans - major clinical trials (which take a long time) would need to be done before the public could get to a treatment. The CNN article is a bit sketchy on details, but it did point out this fact. Thalidomide is an example of treatment which worked in lab experiments but went on to cause chaos with mothers who used it (their babies were born deformed).
Another issue is how it targets cells - it's no good if it targets healthy cells as well. However chemotherapy and radiotherapy also have this side effect so if it kills less cells and is succesful in killing the cancer cells it should be used. But as i said more information (i.e. free access to the original article) would be nice so we could make a more informed opinion on this article.
Just a small quibble:
First: the article was published in Science and is available here.
And you're very right in pointing out that of the vast number of antibody-directed cancer therapies mentioned in the literature, almost all have failed in people. However, there are a few successes - Mylotarg, Ontak, Herceptin, and Rituxan spring to mind. In fact, the Herceptin antibody was one of the antibodies used in this study - which increases the odds of clinical relevance.
Hasta.
"...researchers are testing a microscopic "smart bomb" to target, attack, and kill cancer cells."
I just hope they can tell the difference between my organs and say a Chinese Embassy, or Red Cross Center.
Getting diabetes AND salmonella would be a bad weekend.
Nanogenerators?? good grief. The scientists involved seem to be taking quite a bit of license to make it appealing to the general public. The radioactive atom doesn't 'power' anything.
Radiation therapy (along with chemotherapy) is really a brute force method for dealing with cancer. You use radiation or chemicals to kill cells. It just happens that the cancer cells get killed off faster than normal cells.
The principle of radioimmunotherapy (tagging antibodies with radiactive elements) has been around for quite some time now. The only new and revolutionary part of this particular project seems to be that the radioactivity is encased in a buckyball which is tagged to the antibody. I suspect this is to help keep the activity attached to the antibody. One of the major problems with existing tags is that the radioactive decay breaks the bonds attaching the atoms to the antibody so you end up with a bunch of free radioactivity floating around the body instead of attached to the antibody.
"For I am a Bear of Very Little Brain, and Long Words Bother Me"
There are additional reasons (besides targeting of radiation and susceptability of dividing cells to DNA damage due to activation of otherwise-idle genes) for cancer cells to be more susceptable to radiaion damage.
Because cancer cells are dividing all the time, they tend to be less robust than other cells. Many therapies (including some of the earlier chemotherapy regimens) take advantage of this by poisoning cells ALMOST to the point of death - which pushes cancer cells over the edge. (An exception to this rule is Melanoma, which gets extra energy as a side-effect of making the brown pigment Melanin. This makes it STRONGER than the typical cell.)
Radiation therapy can provoke some of the further-damaged cancer cells into triggering an immune reaction against both themselves and their still-undamaged-but-cancerous neighbors.
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It's nice to see that the monoclonal-antibody-attached-to-local-poison approach is getting into the field. But I'd like to know what happened to:
- Monoclonal antibodies plus radio-iodine for Melanoma. (Sounds like this is the same stunt further tuned, with a different radioactive element for more localized effect.)
- Monoclonal antibodies plus a catalytic poison from a bacterial toxin. (I don't recall the exact toxin used. But it worked by destroying all the copies of one of the enzymes that attached a particular amino-acid to its T-RNA, shutting down protein synthesys. One molecule, one dead cell. And the molecule ended up inside the cell when the cell recycled the part of the surface with the antibody attached. Perhaps that had a variable effectiveness depending on what the antibody targeted. Radiation works from OUTSIDE too, even if you need a lot more copies of it.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
The article evens admits they are not sure that the right cell will be targeted.
At the next eco-hypocrisy-meeting, count the private jets used to get to the meeting. Should be interesting to see that