Researchers from the Mayo Clinic have developed a type of cancer-fighting nanoparticle that is designed to shrink breast cancer tumors and prevent recurrence. In a mouse model, the therapy yielded a 70-80% reduction in tumor size and mice treated with the nanoparticles demonstrated resistance to future tumor recurrence a month later.

The nanoparticle is coated with antibodies that target the HER2 receptor – a molecule found on 40% of breast cancers. The particles target tumors by recognizing HER2 and triggering the immune cells to attack the tumor cells.

“In this proof-of-concept study, we were astounded to find that the animals treated with these nanoparticles showed a lasting anti-cancer effect,” principal investigator Dr. Betty Kim said in prepared remarks. “Unlike existing cancer immunotherapies that target only a portion of the immune system, our custom-designed nanomaterials actively engage the entire immune system to kill cancer cells, prompting the body to create its own memory system to minimize tumor recurrence. These nanomedicines can be expanded to target different types of cancer and other human diseases, including neurovascular and neurodegenerative disorders.”

The nanoparticles alert the body’s macrophages and phagocytes to engulf and destroy foreign material. The clean-up cells then communicate with highly specialized immune cells that eliminate any remaining cancer cells. The T-cells also retain a “memory” of the cancer cells to prevent the cancer from recurring.

“Our study represents a novel concept of designing nanomedicine that can actively interact with the immune cells in our body and modulate their functions to treat human diseases,” Kim added. “It builds on recent developments in cancer immunotherapy, which have been successful in treating some types of tumors; however, most immunotherapy developed so far does not harness the power of the entire immune system. We’ve developed a new platform that reaches tumor cells and also recruits abundant clean-up cells for a fully potent immune response.”

The team plans to evaluate if the nanoparticle therapy can prevent long-term tumor recurrence, including metastases at distant regions from the primary site of the tumor.

“This approach hopefully will open new doors in the design of new nanomedicine-based immunotherapies,” Kim said.