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Nanoparticles for Gene Silencing

When you think of the ultimate medical cure what comes to mind?

For me it’s curing aging but the second cure I think of and the one most people would answer first is probably curing cancer right?

That’s been kind of the iconic future cure that sets the standard.

Well we’ve received a ton of emails about a recent advance that could one day not only treat many cancers but many genetic diseases as well.

The California Institute of Technology in conjunction with bio-tech firm Calando have developed a method to deliver targeted nanoparticles to the genes of cancer cells so that they can effectively be shut down and prevented from growing. This would cause any tumor to essentially starve to death.

This is accomplished using tiny 70 nanometer balls of polymer and protein that sidestep the immune system and attaches itself to cancer cells.

In that nanoparticle ball is a specific package of RNA call siRNA. It enters the cell and releases it’s cargo which prevents the cell from making the proteins it needs to live. Once the package has done its job, it unzips itself into tiny pieces which are then excreted.

RNA or ribonucleic acids are the key molecular machines that cells use to make proteins. When a protein is needed, a copy is made of the dna snippet in a specific gene that codes for that protein. That copy is called mRNA or messenger RNA. It moves out of the protected nucleus of the cell into the cell’s cytoplasm so that other types of RNA can read the mRNA’s instructions and construct the desired protein.

RNA Interference (RNAi) was discovered in 1998 and won the Nobel prize a few years ago. This mechanism evolved to control gene expression. This type of RNA, attaches to other types of RNA to control how active or inactive genes are. If it attaches to mRNA, it can prevent it from making protein just like that gene never existed. This hijacking RNA is called  small interfering RNA (siRNA) and this is exactly what is in the nanoparticle I just mentioned above.

The phase one trials that caltech has done show the follwing key results:
1-The nanoparticles enter the cancer cells
2-The more nanoparticles that are injected, the more that show up in the cell. This is called dose-response effect.
3-And finally, they found evidence that mRNAs were actually degraded preventing them from making proteins.

Here’s why I believe this new technique has excellent potential:

1) Senior author Dr Antoni Ribas, a researcher at UCLA’s Johnson Comprehensive Cancer Center, said:
“There are many cancer targets that can be efficiently blocked in the laboratory using siRNA, but blocking them in the clinic has been elusive.”

So, we know that lots of cancers have already been blocked in the lab using siRNA. The problem for years has been getting it to the cells in a body. This is exactly what these nanoparticles let us do.

2) Dr Mark E Davis, Professor of Chemical Engineering at Cal-tech, told the press that in principle:
“Every protein now is druggable because its inhibition is accomplished by destroying the mRNA.”

Proteins are hard to target because the chinks in their armor can be hidden away in the 3 dimensional folds of the protein. This technique let’s us conceivably target any protein because we can stop it at the mRNA level before its even created. Kinda like killing John Connor’s mother before he’s born.

I have a pet peeve about this news item. Many articles used nanobots in their titles like:

* Human-Tested Nanobot Delivers New Cancer Therapy With Success!
* Nanotech robots deliver gene therapy through blood
* Cancer Gene Therapy by Nanotech Robots

Now I love the nanobot as much as anybody….no…actually I love them a lot more than most people which is why this is annoying.

These nanoparticles are not Nanobots. It’s a tiny ball with RNA in it.

Would you call a chicken egg a robot?
Call them gene silencers or maybe nano trojan horses but please don’t call them nanobots……..thank you

2 comments to Nanoparticles for Gene Silencing

  • Jim Shaver

    There’s one part (okay, one of many such parts) of this process that I don’t understand. These little siRNA bombs are described as “targeted nanoparticles”, but the referenced article makes no mention of how the nanoparticles target only cancer cells and do not harm normal cells. Would these containers have to be designed and consructed specifically for different types of cancers? And if so, how do they (the scientists) do that? Or is it the siRNA that is designed to target only the RNA molecules of the cancer cells? (In which case the nanoparticles could be attaching themselves to healthy cells, too, but causing them no damage.)

  • eean

    Yea I have the same question as Jim. Obviously we have lots of ways to muck up cancer cells, the issues has always been not killing the patient at the same time. So the targeting is the most interesting part.

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