Nano-factories produce cancer drugs at tumor sites

Posted by Kate Taylor

MIT researchers have created a new type of nanoparticle that can synthesize proteins on demand, potentially creating cancer drugs right at the spot they're needed.

Drugs made of protein have shown promise for treating cancer, but are difficult to deliver as they're usually broken down by the body before they reach their destination.

But MIT's 'protein-factory' particles can travel safely to the site of a tumor and be turned on when they reach their targets, by shining ultraviolet light on them.

They could be used to deliver small proteins that kill cancer cells, and eventually larger proteins such as antibodies that trigger the immune system to destroy tumors, says MIT's Avi Schroeder.

"This is the first proof of concept that you can actually synthesize new compounds from inert starting materials inside the body," he says.

The researchers were hoping to target metastatic tumors — those that spread from the original cancer site to other parts of the body, and which cause 90 percent of cancer deaths.

The new nanoparticles self-assemble from a mixture that includes lipids — which form the particles’ outer shells — along with a mixture of ribosomes, amino acids and the enzymes needed for protein synthesis. Also included are DNA sequences for the desired proteins.

The DNA is trapped by a chemical compound called DMNPE, which reversibly binds to it - and releases the DNA when exposed to ultraviolet light.

Waiting until the particles reach their destination before activating them could help prevent side effects from particularly toxic drugs, says James Heath, a professor of chemistry at the California Institute of Technology.

"There are lots of details left to be worked out for this to be a viable therapeutic approach, but it is a really terrific and innovative concept, and it certainly gets one’s imagination going," he says.

The researchers are now working on particles that can synthesize potential cancer drugs. Some are toxic to both cancerous and healthy cells — but this delivery method could allow protein production to be turned on only in the tumor, avoiding side effects in healthy cells.

The team's also looking at new ways to activate the nanoparticles, such as by acidity level or other biological conditions specific to certain body regions or cells.