NanoSapiens

Gene-Silencing Inhaler Shows First Success Preventing Human Disease

Posted on 28. Apr, 2010 by Jeremy Hsu.

Success with silencing respiratory virus could lead to protection for lung-transplant patients and infants

RNA molecules typically help genes make proteins as a basic function of biological existence. But snippets of RNA known as short interfering RNA (siRNA) can destroy other RNA molecules with a complementary sequence of letters.

Scientists targeted the genes of the respiratory syncytial virus (RSV), which is the number-one cause of infant hospitalization in the U.S. but is more or less harmless for adults.

Researchers at the University of Tennessee in Memphis tested a nasal spray containing siRNA or placebo on 85 healthy adults, and then infected all of them with live RSV. Just 44 percent of those who received the gene silencing spray developed infections, compared to 71 percent of the placebo group.

The achievement was made a bit easier in part because respiratory viruses are especially eager to snatch up RNA snippets. And scientists still need a different method of delivering RNAi to cells for non-respiratory diseases. But that hasn't stopped the researchers from following up on their first success by testing the therapy in lung-transplant patients, and perhaps also infants in the near future.

[via New Scientist]

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In First Successful Human Trial, Nanotech Robots Deploy Cancer-Fighting RNA

Posted on 23. Mar, 2010 by Stuart Fox.

Specially constructed molecules could potentially block the expression of genes critical to the reproduction of viruses and the spread of cancer. But until now, doctors had been unable to direct those molecules to the right cellular nuclei. Scientists from the California Institute of Technology solved this problem by placing the RNA molecules in a specialized polymer robot with a chemical sensor. When the environment of a cancerous cell triggered the chemical sensor, the robot releases the RNA.

The trial involved three people with melanomas who received the RNA-load nanoparticles intravenously four times, for 30 minutes, over three weeks. At the end of that time, samples taken from the melanomas showed both the presence of the RNA, and a reduction in tumor gene expression.

This technology still has a long way to go before it becomes a routine medical treatment. However, by targeting the epigenome, the expression of genes, as opposed to DNA itself, it has much more practical potential than genetic therapy. Plus, since RNAi can work against any transcription, RNAi nanobots could potentially disable both DNA viruses, like smallox, and RNA viruses, like SARS.

[Reuters]

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