There’s a new weapon in the battle against lung cancer metastases: red blood cells equipped with nanoparticles that stimulate the immune system to eliminate tumors. Tumors often metastasize to the lungs via the circulatory system, where they shield themselves from circulating immune cells by secreting immunosuppressive chemicals. These metastatic cells then form secondary tumors in the lungs of advanced-stage cancer patients.
Scientists at Harvard’s Wyss Institute have devised a therapeutic system to combat this by leveraging the help of the body’s own immune defenses.
“Our approach is the exact opposite of conventional cancer treatments that focus on getting the immune system to recognize and attack the primary tumor, because those tumors are often large and difficult for immune cells to penetrate,” said Zongmin Zhao, one of the researchers involved in the study.
“We recognized that the high density of blood vessels in the lungs provides much better access to tumors there, offering a unique opportunity to induce an immune response by targeting the metastasis.”
The researchers called the platform the so-called EASI system, with the nanoparticles that latch on to red blood cells known as “ImmunoBait”. The bait here is an inflammatory chemokine called CXCL10 which triggers the activation of immune cells such as leukocytes. Once loaded with ImmunoBait, the red blood cells (which serve to transport oxygen around the body), hold on to their ammunition until they reach the intricate capillary beds of the lungs. In these narrow passages, the red blood cells are forced to squeeze through, where ImmunoBait is released. Antibodies that coat these nanoparticles cause them to attach to the lining of the blood vessels where they recruit immune cells to the scene to destroy tumor cells.
Anvay Ukidve, another researcher involved in the study published in Nature Biomedical Engineering, explained: “Lung metastases deplete certain kinds of chemokines from their local environment, which means the signal that should attract beneficial white blood cells to fight the tumor is gone.”
“We hypothesized that providing that chemokine signal at the tumor site could help restore the body’s normal immune response and enable it to attack the tumors.”