Spongy ‘decoy’ lures in breast cancer cells

"We set out to create a sort of decoy—a device that's more attractive to cancer cells than other parts of the patient's body," says Lonnie Shea. "It acts as a canary in the coal mine. And by attracting cancer cells, it steers those cells away from vital organs." (Credit: Joel Carranza/Flickr)

A small, implantable device that acts like a cancer “super-attractor” could one day give doctors earlier warnings of relapse in breast cancer patients and could even slow the disease’s spread to other organs.

The sponge-like device is designed to attract cancer cells that emerge in the bloodstream during the early stages of cancer’s recurrence—before tumors form elsewhere in the body.

A new study with mice shows that the device attracts detectable numbers of cancer cells before they’re visible anywhere else. In the study, cancer cells spread to the lungs 88 percent more slowly in mice that received the implants.

researcher constructs cancer decoy scaffolds
Researchers construct cancer “super-attractor” scaffolds from mouse tissue, using a tumor as a control . (Credit: U. Michigan)

Researchers envision the super-attractor being implanted just beneath the skin of breast cancer patients. Doctors could monitor it using a noninvasive scan and use it to detect and treat relapse sooner. The device also has the potential to be used as a preemptive measure in those who are at high risk for breast cancer.

[Some breast cancer cells are like ‘stem cells gone bad’]

“Breast cancer is a disease that can recur over a long period in a patient’s life, and a recurrence is often very difficult to detect until the cancer becomes established in another organ,” says Jacqueline Jeruss, associate professor of surgery at the University of Michigan’s Comprehensive Cancer Center. “Something like this could be monitored for years and we could use it as an early indicator of recurrence.”

The idea for the super-attractor stemmed from the knowledge that cancer cells don’t spread randomly. Instead, they’re attracted to specific areas within the body. So the team worked to design a device that exploited that trait. Their findings are published in the journal Nature Communications.

“We set out to create a sort of decoy—a device that’s more attractive to cancer cells than other parts of the patient’s body,” says Lonnie Shea, chair of biomedical engineering. “It acts as a canary in the coal mine. And by attracting cancer cells, it steers those cells away from vital organs.”

‘A brighter beacon’

The device takes advantage of interaction that naturally takes place between cancer and the body’s immune system. Cancer co-opts the immune system, turning a patient’s immune cells into drones that gather in specific organs to prepare them for the arrival of cancer cells. The immune cells then act like a beacon in the body that attracts cancer to that location. In essence, the team has built a brighter beacon.

illustration of implant
This illustration offers a conceptual look at how an implantable sponge-like device attracts cancer cells from the bloodstream. (Credit: U. Michigan)

When the super-attractor was implanted just beneath the skin of the mice in the study, their cancer-compromised immune systems responded as they would to any foreign object, sending out cells to attack the intruder. Cancer cells were then attracted to the immune cells within the device, where they took root in tiny pores designed to be hospitable to them.

Further, the cells the implant captured didn’t group together into a secondary tumor, as they normally would.

“We were frankly surprised to see that cancer cells appeared to stop growing when they reached the implant,” Shea says. “We saw individual cells in the implant, not a mass of cells as you would see in a tumor, and we didn’t see any evidence of damage to surrounding tissue.”

[Bacteria build ‘coat’ for medical implants]

The team is evaluating noninvasive scanning technologies that could be used to monitor the device.

The device’s spongy structure is particularly attractive to circulating cancer cells. It’s made of an FDA-approved material that’s already widely used in surgical sutures and dissolves in the body over time. The device implanted in the mouse study was only a few millimeters in diameter. A human-sized version might be a bit larger than a pencil eraser.

While it’s likely several years away from patient use, the technology could potentially be used for other types of cancer as well, including pancreatic and prostate cancer. And it could be an important tool in the emerging field of precision medicine, where captive cells could be analyzed to identify the best therapies for individual patients.

[device smushes cancer to see if it’s squishy]

The team is now working to better understand why cancer cells are attracted to specific areas of the body and why they’re so strongly attracted to the device. This information could lead to new insight into how cancer metastasizes and how to stop it, Shea says.

“A detailed understanding of why cancer cells are attracted to certain areas in the body opens up all sorts of therapeutic and diagnostic possibilities. Maybe there’s something we can do to interrupt that attraction and prevent cancer from colonizing an organ in the first place.”

The National Institutes of Health and the Northwestern H Foundation Cancer Research Award funded the work. The university is pursuing patent protection for the intellectual property.

Source: University of Michigan