Existing RNAi delivery usually relies on polymers or lipids, which, while sometimes effective, can be risky and difficult to target. Researchers at the Massachusetts Institute of Technology, in cooperation with Harvard and Alnylam Pharmaceuticals ($ALNY), are using DNA origami to create a safe, targeted and biodegradable platform for the therapy.
RNAi therapies can silence genes expressed in tumors, forcing cancer cells to, say, perish, but delivery has been vexing for researchers trying to progress the treatment. In a paper published in the latest Nature Nanotechnology, the research team described their method of using DNA origami to create custom molecules for the RNAi treatment, allowing it to seek out tumor cells and deliver its therapy.
The scientists fused 6 strands of DNA, creating a tetrahedron, and affixed a strand of RNA to each edge. They then added proteins to each tetrahedron that would seek out and bind to tumor cells. Testing the method in mice implanted with human tumors, the researchers found that the treatment hung around in the bloodstream long enough to bind to its target and deliver the treatment. The molecule was made to target a certain gene in the tumor, and the scientists found that the RNAi cut down the gene's expression by more than half.
In future studies, the team wants to apply the method to target the genes that promote cancer growth. However, these early trials demonstrate the value of DNA origami as a drug delivery platform, MIT researcher David Anderson said in a statement. "What's particularly exciting about nucleic acid origami is the fact that you can make molecularly identical particles and define the location of every single atom," he said.
This is another application for the nascent DNA origami technology. Developed in 2006, the concept of self-assembling, customizable drug carriers has piqued the interest of researchers around the world and could lead to more effective ways of administering treatments for cancer and infectious diseases.
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