Body's blood-clotting machinery harnessed against cancer

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Next time you accidentally cut yourself, take a moment to appreciate how your body's various defenses work together, even communicate with one another, to first detect the injury to a blood vessel, then deploy the proteins that interact in complex chains to form strands of fibrin, which then clots and seals the wound. A team of researchers at MIT, the Sanford-Burnham Medical Research Institute and the University of California at San Diego were sufficiently impressed by this natural communication process that they decided to see if they can imitate it with nanoparticles and harness it to deliver anti-cancer drugs to tumors. The result was a paper published in the journal Nature Materials in which they describe how they coaxed nanoparticles to communicate with one another while deploying a two-wave assault on a tumor.

They created two types of nanoparticles--one that signals and another that receives. The signaling particles slip through tiny holes in the leaky blood vessels that usually surround tumors. These particles trick the body into believing an injury has occurred at the tumor site, much like the body detects an accidental skin cut. That signals the second wave of nanoparticles, which rushes to the scene and, since they are coated with proteins that bind to fibrin, bind to the site of clotting. While they're there, they release a drug payload into the tumor.

This communication system has already worked on mice, delivering more than 40 times more of the anti-cancer drug doxorubicin than nanoparticles that did not communicate. Omid Farokhzad, of Brigham & Women's Hospital in Boston, praised the new method as a big improvement over other types of nanoparticles, which typically deliver only two to seven times the dose of conventional delivery methods. Farokhzad told Nature News that the researchers are "on the right path," but much work remains to be done before it can translate to the clinic.

To help hurry that alone, the MIT researchers are exploring ways to replace components of these cooperative nanosystems with drugs already being tested in patients.

- read the release
- and a story in Nature News
- read the abstract in Nature Materials

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