Magnetic nanoparticles target human cancer cells

Georgia Tech scientists follow up their 2008 study on mice with findings that these nanoparticles target and attach themselves to human cancer cells just as effectively, then remove them from the body.

In 2008, scientists at the Georgia Institute of Technology and the Ovarian Cancer Institute developed a potential treatment to fight cancer using magnetic nanoparticles designed to attach themselves to cancer cells. They found in their groundbreaking tests on mice that the particles not only attached to cancer cells, but they also moved those cells.

Nanoparticles, in brown, attach themselves to cancer cells, in violet, from the human abdominal cavity. Ken Scarberry/Georgia Tech

In what may well prove to be some of the most exciting health news in the year to come, the group announced in the journal Nanomedicine in December and further publicized on Tuesday that it has replicated the study on human cancer cells, with the nanoparticles appearing to be every bit as effective.

Lead Georgia Tech researcher Ken Scarberry explains how it works:

Often, the lethality of cancers is not attributed to the original tumor but to the establishment of distant tumors by cancer cells that exfoliate from the primary tumor. Circulating tumor cells can implant at distant sites and give rise to secondary tumors. Our technique is designed to filter the peritoneal fluid or blood, and remove these free-floating cancer cells, which should increase longevity by preventing the continued metastatic spread of the cancer.

The idea came to Scarberry when he was a Ph.D. student at Georgia Tech. Originally, he thought he could use magnetic nanoparticles to extract viruses and virally infected cells, and his adviser suggested that he also investigate their effect on cancer cells.

He published his first paper on the particles targeting cancer cells in the Journal of the American Chemical Society in July 2008. In that paper, he and his adviser, biology professor and associate dean John McDonald, showed that by giving mice cancer cells a fluorescent-green tag and staining the magnetic nanoparticles red, they were able to apply a magnet and move the green cancer cells to the abdominal region.

Today, McDonald and Scarberry, who is now a post-doc in McDonald's lab, are "primarily interested in developing an effective method to reduce the spread of ovarian cancer cells to other organs," says McDonald, who is also chief research scientist at the Ovarian Cancer Institute.

Specifically, ovarian cancer cells highly express a receptor called EphA2, while the nanoparticles are functionalized with ligands (more specifically, an ephrin mimetic peptide) that bind with high affinity to the EphA2 receptor in the ovarian cancer cells.

In this latest round of testing, their technique appears to work as well at capturing cancer cells from human patient samples as it did in mice. The team says its next step is to test whether the technique works in live animals, instead of just cells; if it does, they'll move on to test it on actual people.

Scarberry adds that it is possible to apply this same technology to other cancer cells or pathogens by using ligands that bind to receptors expressed specifically by those cells or pathogens. So this could be big news across several cancers, not just ovarian.

Update, 11:15 a.m. PST: Updated with details from Scarberry on how the magnetic nanoparticles have an affinity for the ovarian cancer cells.

 

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