“Bed-of-nails” breast implant deters cancer cells.
Researchers at Brown University have created an implant with a modified surface that seems to prevent breast cancer cells from growing back after an operation to remove cancerous tissue. The implant, made from an FDA-approved biodegradable polymer with its surface changed at the nanoscale level, causes a reduction in the blood vessel architecture that breast cancer tumors depend upon, while at the same time attracting healthy endothelial cells for breast tissue. Their research results have been published in the journal Nanotechnology.
One in eight women in the United States will develop breast cancer during her lifetime. Many of these women undergo surgery to remove the tumor and often undergo some kind of breast reconstruction afterward. Of these women, one in five will see their cancer return, according to the American Cancer Society.
Looking to create materials that might drive down that rate of relapse, the researchers created an implant with a surface structured like a “bed-of-nails” at the nanoscale level that deters cancer cells from dwelling and thriving. A nanometer is one-billionth of a meter, or 1/50,000th the width of a human hair.
“We’ve created an (implant) surface with features that can at least decrease (cancerous) cell functions without having to use chemotherapeutics, radiation, or other processes to kill cancer cells,” says Thomas Webster, associate professor of engineering and the corresponding author of the research paper. “It’s a surface that’s hospitable to healthy breast cells and less so for cancerous breast cells.”
Webster and his lab were already modifying various implant surfaces to promote the regeneration of bone, cartilage, skin, and other cells. In this work, he and Lijuan Zhang, a fourth-year graduate student in chemistry, sought to reshape an implant that could be used in breast reconstruction surgery that would not only attract healthy cells but also repel any lingering breast-cancer cells. They created a cast on a glass plate using 23-nanometer-diameter polystyrene beads and polylactic-co-glycolic acid (PLGA), a biodegradable polymer widely in clinical settings, such as stitches. The result is an implant whose surface is covered with adjoining, 23-nanometer-high pimples. They also created PLGA implant surfaces with 300-nanometer and 400-nanometer peaks for comparison.
In the lab they found that after one day, the 23-nanometer-peak surfaces showed a 15-percent decrease in the production of the VEGF protein upon which endothelial breast cancer cells depend, compared to an implant surface with no surface modification. They also found that the 23-nanometer semispherical surface yielded 15 percent more healthy endothelial breast cells compared to normal surface after one day of lab tests.
The 23-nanometer surface showed greater reduction in VEGF concentration when compared to the 300-nanometer and 400-nanometer-modified implants as well. Webster thinks this may be because the bumpier surface makes it more difficult for the tumor cells, which tend to be stiffer than normal cells, to wrap themselves around the contours, take hold, and thrive.
“This is like a bed-of-nails surface to them,” says Webster. “I would guess that surface peaks less than 23 nanometers would be even better, although polystyrene beads with such dimensions don’t yet exist. “The more you can push up that cancerous cell, the more you keep it from interacting with the surface.”
Webster and Zhang next plan to investigate why the nano-modified surfaces deter malignant breast cells, to create surface features that yield better results, and to determine whether other materials can be used. Their research was funded by the National Institutes of Health’s National Center for Research Resources and the Memorial Hermann Foundation, a group connected to the largest not-for-profit healthcare system in Texas.
By MARIE DAGHLIAN