The top 10 Health Stories of 2009 – Harvard Health Letter

by Chris on December 4, 2009

in News

#6 These micros are major

Messenger RNA reads the DNA of our genes and uses that code to assemble proteins, the building blocks of all forms of life. In the mid-1990s, researchers discovered small bits of RNA, now known as microRNA, that attach to the messenger version and switch it off, so the protein doesn’t get made.

Already microRNAs are playing an important role in helping cancer doctors make more accurate diagnoses and prognoses and choose more effective treatments. For example, in 2009, researchers reported that liver cancer patients whose tumors had lower levels of a particular microRNA, called miR-26, had a much worse prognosis, but also a better response to one kind of treatment.

Promising results for macular degeneration and respiratory syncytial virus infection have been reported in humans, and successful treatments using microRNAs have been achieved in mice. Results of a mouse study showed that delivering miR-26 to liver cancer cells made them behave more like normal cells. Another study in mice showed that delivering a different microRNA to breast cancer cells prevented them from metastasizing.

Compared to drugs, microRNAs are easy and cheap to manufacture. For cancer, they would mean treatment targeted at the root cause of the disease: mutated genes promulgating wayward proteins. And researchers have high hopes that microRNA medicine will yield pinpoint control, so only diseased cells would be affected. But there’s also reason to mix in some caution with the optimism. MicroRNA research is, after all, in the beginning stages and has a good ways to go before maturing into full clinical reality. Toxicity could be a big hurdle if therapeutic microRNA accidentally interferes with messenger RNA that shouldn’t be interfered with. (read more)

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