KAIST researchers have developed a new therapeutic method that aims to convert immune cells found within tumors into anticancer cell therapies. The research, led by Professor Ji-Ho Park from the Department of Bio and Brain Engineering at KAIST, introduces a process where a drug is injected directly into a tumor. This drug is absorbed by macrophages—immune cells already present in the body—which then produce CAR (chimeric antigen receptor) proteins and transform into "CAR-macrophages."
Solid tumors such as those found in gastric, lung, and liver cancers are known for their dense structure, which makes it difficult for immune cells to enter or function effectively within them. As a result, current immune cell therapies often have limited success.
CAR-macrophages are being explored as an emerging form of immunotherapy because they can engulf cancer cells directly and also activate nearby immune cells to enhance the body's anticancer response. However, traditional methods require extracting immune cells from patients’ blood, culturing them outside the body, and genetically modifying them—a process that is time-consuming and expensive.
The KAIST team sought to address these challenges by focusing on macrophages already present around tumors. They used lipid nanoparticles containing mRNA with cancer-recognition instructions along with an immunostimulant designed to activate immune responses. These nanoparticles are easily absorbed by macrophages.
According to the researchers: "In this study, CAR-macrophages were created by 'directly converting the body's own macrophages into anticancer cell therapies inside the body.'"
When tested in animal models of melanoma—a severe type of skin cancer—the treatment significantly slowed tumor growth. The results also suggested that this approach could trigger systemic immune responses beyond just the treated tumor site.
The study was led by Jun-Hee Han, Ph.D., as first author and published on November 18 in ACS Nano. Funding came from Korea’s National Research Foundation through its Mid-Career Researcher Program.
