Israeli researchers have developed nanoparticles that slowed the growth of aggressive breast cancer tumors in preclinical models without carrying chemotherapy, antibodies or any other drugs, TPS-IL reported citing the Technion Israel Institute of Technology.

The findings, published recently in the peer-reviewed journal ACS Nano, suggest a different approach to cancer treatment: instead of delivering a toxic or targeted drug into the tumor, the particles appear to work by simply changing the tumor’s immune environment and blocking harmful interactions that help cancer grow.

“This is better than the existing treatments with antibodies or chemotherapy, which have many side effects,” Professor Assaf Zinger, who led the study, told The Press Service of Israel.

The study focused on “triple-negative” breast cancer, a form of the disease considered especially aggressive and difficult to treat. It often progresses quickly and is less responsive to several standard therapies because it lacks the biological markers targeted by many existing breast cancer drugs.

The researchers designed nanoparticles called MPsomes to interfere with the tumor microenvironment, the biological surroundings that help tumors survive, grow and avoid immune system attacks.

Cancer cells can manipulate immune cells in their environment, Zinger explained. Among them are macrophages, white blood cells that normally help protect the body. In some tumors, macrophages are drawn into the cancer’s orbit and begin supporting tumor growth rather than fighting it.

According to Zinger, the MPsomes act as a biological decoy. They compete for binding sites in the tumor environment and help prevent harmful immune cells from gaining access to the tumor and supporting its development.

“Instead of directly attacking cancer cells using chemotherapy or antibodies, we know how to do this using nanoparticles that carry no medicine and disguise themselves as white blood cells,” Zinger told TPS-IL. “Then they compete with white blood cells over binding sites in the tumor area, and then those white blood cells that would have helped the cancer simply do not get there. As far as I know, we are the first to prove that empty particles — meaning particles that carry no medicine — can behave this way.”

Zinger added that the nanoparticles accumulated at high levels around the tumor and slowed tumor growth at a level comparable to existing treatments.

The study also found that the nanoparticles changed the immune cell composition around the tumor. There were fewer immune cells associated with tumor support and more cells associated with attacking it.

“In female mice, the tumor shrank very significantly. We proved that the empty particles really prevent the development of the tumor,” Zinger said.

Another potential advantage is production. According to the Technion, the method developed by the researchers can produce about 20 milliliters of nanoparticles per minute, or roughly 1.2 liters per hour.

The base of the particles is made largely from materials classified by the U.S. Food and Drug Administration as generally recognized as safe, a designation that could help future development if the technology advances toward human testing.

Zinger emphasized that the work is still at the preclinical stage and has so far been tested only in mouse models. Clinical trials in humans would be needed before the approach could be considered for medical use.

“My dream is to get this to the clinic. The expected timeline is at least eight years, and we will approach the FDA within two years,” Zinger said. “I think that in a challenging period, discovering scientific findings that can spread light, that is our message, and that is why I do what I do.”