February 3rd, 2007
How silicon-based drugs could treat cancer
The lives of almost living organisms on Earth, including ourselves, are carbon-based. And when we're sick, we're exclusively treated with carbon-based medicines. But now, a team of chemists at the University of Wisconsin-Madison had a bright idea. Why not replace carbon atoms by silicon atoms? And by modifying a drug named indomethacin, used to treat arthritis and some cancers, they found that silicon medicines may have extraordinary therapeutic value for treating human disease. The modified drug both slowed the growth of cancer cells and killed cancer cells directly. Right now, the researchers only have worked with a specific drug — and in their labs. So I guess a vast amount of work needs to be done before silicon-based drugs could be used on humans.
This research has been conducted by Robert West, "one of the world's leading authorities on silicon chemistry," and by his colleagues at the Organosilicon Research Center of the University of Wisconsin.
They decided to start with a drug named indomethacin, which is sometimes used to treat arthritis and some cancers, but that many physicians avoid because of its toxicity.
For those of you who want more details about the indomethacin drug, you can read this page at Wikipedia. You also can read an October 13, 2005 news release from the Imperial College London, "Helping drugs get around: research points way to more effective delivery of medicine around the body," from which the illustration below has been extracted. It shows "phenylbutazone (blue) and indomethacin (yellow) bound to human serum albumin in the presence of fatty acid (grey and red spheres)." (Credit: Imperial College London)
So were the experiments successful?
Tested on cancer cells in cultures, the modified drug both slowed the growth of cancer cells and killed cancer cells directly. The high activity was against pancreatic cancer cells. This is important because pancreatic cancer responds poorly to any therapy and is almost always fatal because it is hard to detect and spreads rapidly.
The researchers also found that "the silicon-modified molecule exhibited far less toxicity than the all-carbon-based form of the drug." But as they've only tested their modified drug on cancer cells in cultures, it's difficult to understand how they tested for toxicity.
This research work has been featured in the Silicon Chemistry published by Springer Netherlands under the name "Novel silicon-containing drugs derived from the indomethacin scaffold: Synthesis, characterization and evaluation of biological activity" (Volume 3, Numbers 3-4, Pages 209-217, January 2007). Here is a link to the abstract.
So will we see silicon-based drugs in a near future? I don't think so, but at least the idea is new and brilliant.
Sources: Terry Devitt, University of Wisconsin-Madison, January 24, 2007; and various other websites
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