Triple-helix RNA cancer treatment from MIT shows major promise

 

 Most cancer treatments rely on killing cancer cells just a little more than they’re killing non-cancer cells. It’s far from ideal, but it’s the best we’ve got right now. There are a number of promising ideas on the horizon, and the latest is a new treatment developed at MIT that relies upon triple-helix RNA. In preliminary tests with mice, these bundled snippets of nucleic acid increased survival times several fold.
There are two main types of nucleic acid in your cells, DNA (in the nucleus mostly) and RNA (carries information elsewhere in the cell). This research focuses on the role RNA plays in the development of cancer, specifically a type of RNA known as microRNA (often abbreviated miRNA). These short strands of genetic material help regulate gene expression, which is one of the things that goes haywire in cancerous cells. By introducing new strands of miRNA, the MIT researchers hope to bring cancer under control.
A strand of miRNA is complementary to some sequence of messenger RNA that a cell produces in order to make proteins. The messenger RNA links up with a ribosome to actually build a protein, and a matching miRNA strand gets in the way of that by sticking to its complementary sequence. At least, that’s the way it’s supposed to work. Cancer is really a lack of growth regulation, and some types of miRNA are degraded in cancer cells while others are enhanced.

The therapy developed at MIT uses a triple helix of miRNA suspended in a gel polymer. The triple helix is considerably stronger than a single or double strand, meaning it can be absorbed into a tumor cell when the gel comes into contact with it. After it’s absorbed, the helix separates and two of those miRNA strands go to work (the third is just for stabilizing the helix). One strand mimics a naturally occurring miRNA that is degraded by cancers, and the other blocks a miRNA that’s overactive in cancer cells.
Researchers used this miRNA gel on nasty triple-negative breast tumor cells that were implanted in mice. The gel treatment alone was able to shrink the tumors by 90% and increased survival to 75 days. Traditional treatments and the use of single/double strand miRNA resulted in a mere seven-day average survival time.
The team is looking for more miRNA combinations that could suppress tumors. The active strands in the helix could even be swapped out based on the type of cancer a patient has. We’re still a long way from trying this in humans, but even by the standards of early studies this one is impressive.