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Within a minute the drugs, using the new nanoparticle delivery system, are already clustering at tumor sites.  (Source: Case Western Reserve University)
New technology using gold nanoparticles attacks tumors faster, more aggressively

While developing new cancer killers is an important priority, half the difficulty in winning the battle against cancer is just getting the drugs to the tumor itself.  The concept of drug delivery is an important one as current blood borne chemotherapy treatments take two or more days to reach the tumor fully. 

Lots of exotic methods have been devised to cut drug delivery time, but one of the more promising ones comes from a new breakthrough from researchers at Case Western Reserve University.  The researchers successfully tested a new delivery system, which brought cancer drugs to tumors in lab mice within a couple hours of their injection.

To accomplish this ultra-speedy delivery, researchers used gold nanoparticle vectors to deliver photodynamic therapy (PDT) drugs, a class of drugs that burn away cancer with light via wavelength energization, to tumors.  Case Western Reserve University graduate student Yu Cheng, one of the paper's coauthors explains, "Gold nanoparticles are usually not used for the PDT drug vector.  However, gold is chemically inert and nontoxic."

PDT drugs, which are seeing increasing use due to their efficacy, are typically difficult to use properly.  In order to prevent the drugs from being prematurely activated, the patient must stay in dim light for days until the drugs reach the tumor.  With the new method, the drugs become much more useful, as the inconvenience is lessened to a mere couple of hours.

Paper co-author Clemens Burda, associate professor of chemistry and director of the Center for Chemical Dynamics and Nanomaterials Research at Case Western Reserve University states, "By shortening the waiting time from drug injection to activation, PDT patients are much less inconvenienced and tend to have a more normal lifestyle."

The new delivery device consists of a gold nanoparticle (Au NP) at its core.  Gold nanoparticles are selected due to their low toxicity, versatile surface chemistry, large surface-to-volume ratio, and variable size and shape.  The nanoparticle is then coated in fatty polyethylene glycol (PEG) ligands, which make it resemble a hairy ball.  The coated molecule does not react with proteins and is fat and water soluble, making sure it reaches the tumor intact. 

A photodynamic chemotherapy drug (Pc 4) is inserted between each of the PEG ligands, coating the ball with cancer drugs.  This particular drug was developed by Case Western Reserve's Malcolm Kenney, professor of chemistry.  The combined nanoparticle gravitates towards tumors within hours, thanks to much faster dispersion.  When it reaches the site, scientists use focused red light to excite the PDTs and fry the tumor. 

A small 1/4-mL injection holds 100 million Au NPs each with 100 PDT drug molecules hitching a ride.  The researchers hope to adapt the coated Au NP system to a broad variety of bloodstream drugs to speed treatment.

In test on mice, the drug was injected in the mice's tails and within in minutes the drug was gravitating around tumors in the mice's bodies.  Human trials, following the successful mouse trials have not yet been planned.  The Food and Drug Administration (FDA) will have to approve the combined particle.  This may be coming soon, though as the components -- Au Nps, PEG ligands and Pc 4 -- are all FDA approved.

The researchers hope to focus their future efforts on modifying the PEG "hair" ligands" for speed and specificity.  Also, they hope to optimize and minimize drug and material load for a finished treatment.  Professor Burda says the beauty of the technology is that such adaptations and optimization can easily be made.

Says Professor Burda, "The system is very modular.  We can change the size and shape of the Au core NPs and we can change the functionality of the PEG ligands. This should lead to optimization of the drug targeting and therapy. If our research is successful, other researchers might adapt this drug delivery system to other diseases and applications."

The team's findings are reported in a paper in the current issue of the Journal of the American Chemical Society.

The research was funded by the National Science Foundation, National Institute of Health/National Cancer Institute and the Biomedical Research Technology Transfer Center.

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i've heard this before
By jlips6 on 7/23/2008 2:34:52 PM , Rating: 2
I recall an earlier article talking about using these gold nanoparticles to latch on to cancerous cells and kill them by frying the cells with radio waves. Is this just a different use of the same technology?




RE: i've heard this before
By TheDoc9 on 7/23/2008 2:55:42 PM , Rating: 2
I'm still waiting for the other shoe do drop on these nano-particles. Probably nothing really bad will happen but suppose some of them get stuck in the persons brain, or perhaps lodged in liver and kidney tissue, what then?

These exotic treatments are great but in addition people should also be educated on proper diet and lifestyle throughout every year of school.


RE: i've heard this before
By Regs on 7/23/2008 3:06:08 PM , Rating: 2
Diet? I don't want my kid growing up deprived of everything however I sure hell don't want him growing up to be obese and unhealthy.

I still blame most cancer on DNA make-up and genetics. Just to put things in perspective, mo point growing up without treating yourself to the "fine" things in life, only to die in a car crash as a young adult.

Any progress in treating cancer patients with medicine is good news to me!


RE: i've heard this before
By omnicronx on 7/23/2008 4:09:42 PM , Rating: 2
quote:
I still blame most cancer on DNA make-up and genetics.
You keep on believing that. It has been well documented that Cancer is more common in overweight people. The evidence on weight is strongest for post-menopausal breast cancer and cancer of the endometrium , gall bladder and kidney.

Basically it could go two ways, the more likely scenario is that obesity in one way or another makes it more likely for someone to have cancer. OR the very unlikely scenario that obese people have been passing down cancerous genes for generations that non obese people are less likely to have.


RE: i've heard this before
By oab on 7/23/2008 5:19:15 PM , Rating: 2
Or, some people through various genetic things are more vulnerable to cancer causing things in the air and water.

The genes don't CAUSE them to get it, they are just more vulnerable IF exposed. (ie. expose a bunch of fruit flies to radiation and at xxx dosage some will die, but other will survive and reproduce).


RE: i've heard this before
By William Gaatjes on 7/23/2008 5:54:13 PM , Rating: 2
Don't forget viruses. They are very common and we are infected all the time. But since our bodies are always maintaining themselves we don't really notice it until we get a nasty one.

You can see it for example with people who have no immune system. Bacteria, fungee and viruses are creating havoc.

Viruses are a lot more common then on would think.

But i am curious about 1 thing that i do not understand...
Tumors usually need a lot of blood to keep on growing.
Are these drugs depending on the fact that tumors need large amounts of blood and therefore the chance that these drugs will end up in the tumor is big ?
Because i would think that our brain likes a lot of blood too.

What am i not seeing here ?


RE: i've heard this before
By William Gaatjes on 7/23/2008 6:11:44 PM , Rating: 2
I agree with Omnicronx, it is true. Cancer is quite common.

I once read an article that fat tissue is a perfect storage for unhealthy chemicals. Chemicals that can cause cancer direct or indirect.

I think for example of dioxines in cowmilk and fatty tissue from cows. The dioxines accumulate inside fatty tissue.

Most people think fat is bad, but we need a healthy amount of fat(or lipids) to transport chemicals(We depend on but do not want floating freely in our blood.) through our bodies.

The more fat you have, the bigger the chance is you have a lot of dangerous chemicals inside you.

Also our blood is pumped around because of our hart.
But our lymphatic system depends on active movement of skeletal muscles for the fluids to be moved around. These fluids are filled with contaminated immune cells. Some of these cells can carry cancer cells. If you do not move much, which is usually the case with obese people your lymphatic system can fail to do it's work properly.
Therefore increasing the chance of cancer.

This is one reason why people start to feel more well when they sport, their lymphatic system is cleaned up.

If you connect the dots it is all quite simple.


RE: i've heard this before
By tmouse on 7/24/2008 9:02:26 AM , Rating: 2
Ok I would like to clarify a few points; first this is not an improved targeting system it is an improved delivery system. The differences may seem subtle but are important. The targeting in these experiments is purely random, as should be evident by the enormous fluorescent region not included in the circled tumor. This method also accumulates the photoreactive agent in the lungs and kidneys. The important part is not the gold nanoparticles (which I suppose if far sexier than the real important component good old polyethylene Glycol). Most nanoparticles have very fast delivery times the 2 day versus 2 hour time reduction is comparing the nanoparticle conjugate to the free photoreactive compound which is not very soluble in water. There is no data suggesting the gold nanoparticle is any more efficient than any other, although it is biologically inert.

In response to a few posts by William Gaatjes viruses are a large factor in cancers of certain animal species but are minimal at best in human cancers for reasons currently unknown. There is no doubt a healthy lifestyle is the best insurance, the immune system probably eliminates over 99% of mutant cells (ok that number was pulled from my anal orifice but it is a very high albeit it unknown percentage). Of course it will not guarantee it if you were dealt a bad hand in the genetic poker game. In regards to nurture versus nature for the majority of cancers is sort of a chicken and egg situation. There are causative links between certain mutations and cancer and strong links between cancer susceptibility and existing alleles in the human genome. In the case of mutation it affects the machinery directly, now the mutation itself can be due to random errors in replication or correction, or it can be caused by outside agents like free radicals. The same with the alleles which increase susceptibility, if the trigger event does not happen, no cancer. You and omnicronx are right about the correlations of fat content and increased cancer risks. Fat can have several mechanisms; first lipid peroxidation can form free radical formation which in turn plays havoc with DNA, and many organic compounds especially heterocyclic compounds are fat soluble allowing for retention and biomagnifications, the breakdown of these compounds results in reactive intermediates which can start the genetic cascade toward cancer.


RE: i've heard this before
By Jaybus on 7/24/2008 10:12:27 AM , Rating: 2
Yes. There is a big difference between targeting and delivery. The targeting, in this case, is essentially the targeting of the light used to activate the PDT agent. I assume they use a red laser and target by focusing. That may well be looked upon as better targeting, however, since damage to normal cells in the area should be far less than that caused by systemic use of chemotherapy agents (or radiation treatment for that matter). That assumes, of course, that the NP/PDT agent is itself relatively non-toxic.

There is a new drug, PV-10, currently in phase 2 trials that apparently works by truly targeting cancer cells. See http://www.clinicaltrials.gov/ct/show/NCT00521053. It is currently in phase 2 trials for melanoma, but apparently could potentially be used on other solid tumors. The results from the phase 1 study were astounding.


RE: i've heard this before
By tmouse on 7/24/2008 1:20:21 PM , Rating: 2
Err no; The light is not the targeting mechanism, it is the trigger. In this case the targeting mechanism is the fact that tumors have "leaky" arterial systems that can allow more of the vehicle to penetrate and become available for absorption through the cell membrane. That’s it. There is nothing tumor specific, it is somewhat more specific than general chemo but not by much. It IS better for this payload since the photoreactive agent is usually not very soluble in water.

In the study you linked to the targeting mechanism is a catheter, it is an Intralesional injection for chemoablation using 10% rose bengal disodium; unless you had the wrong link. There isn’t any specific frequency of energy that is tumor specific.


RE: i've heard this before
By tmouse on 7/25/2008 7:41:09 AM , Rating: 2
Having given your reply additional thought I see where you consider the laser the targeting system, ie zapping the tumor and trying to avoid other tissues that may also have taken up the photoreactive payload. That is more specific than the current systemic toxin chemo and so could be considered a plus. The difference is in magnitude, I feel delivering payloads to nonspecific tissues is still a poor mechanism. This procedure requires vascularization so the probability of malignant metastasis is vastly increased. Killing the main tumor but being unable to target metastases is, in my opinion, poorer than the systemic approach. An ideal targeting system would recognize the tumor cells thus targeting the primary and potential secondaries. The problem is we have been looking for decades and only found a handful of tumor types that have targets. Most tumors are barely different (on their surfaces) from normal, probably because our exceptionally efficient immune systems destroy the more divergent cells before they can even form tumors. So my point is if a payload was taken up by lets say brain tissue, you could not use a laser to kill the primary in the brain where general chemo would work since neural tissue is not mitotically active (I’m vastly oversimplifying the problem i.e. blood/brain barrier ect.)


RE: i've heard this before
By William Gaatjes on 7/25/2008 3:20:01 PM , Rating: 2
It's not that easy to track viruses in a healthy human being.

I know there is a link between cancer in the cervix or uterus of women and sexual transmitted virus named human papilloma virus - HPV.

And there is research done where they found oncorna viruses in brain tumors.

I am sure when the research equipment improve more they will find more leads.


RE: i've heard this before
By Moishe on 7/23/2008 3:11:08 PM , Rating: 2
Maybe cancer patients will now get mugged for their blinged out gold particles. I'm sure if we add the word "nano" and add white earbuds, the muggings will go up.


If I ever had cancer...
By Amiga500 on 7/23/2008 3:05:28 PM , Rating: 3
Could I not allow doctors to try a experimental method on me?

I'd much rather have that than rot slowly.

Or do these guys have a veto?

The Food and Drug Administration (FDA) will have to approve the combined particle.

It might be a good way to speed up research, as scientists would get much more information, much quicker than current - I reckon most people would have a similar outlook on it as me when faced with death.




RE: If I ever had cancer...
By Master Kenobi (blog) on 7/23/2008 3:34:37 PM , Rating: 5
If I'm terminally ill and they want to try some crazy stuff on me that may or may not work, go right ahead. I'm dead anyways, might as well get some solid research results done before I kick over.


RE: If I ever had cancer...
By Fnoob on 7/24/2008 8:30:51 AM , Rating: 2
When you kick over will you turn into a pile of robes? Or will we have to construct a funeral pyre? Either way, any cancer that dare strike you down will only make you more powerful than we could possibly imagine!