Scientists at KAIST in South Korea have developed a novel therapy that transforms a tumor's own immune cells into potent cancer fighters directly inside the body. By injecting lipid nanoparticles into tumors, the treatment reprograms macrophages to produce cancer-recognizing proteins, overcoming barriers in solid tumor treatment. Early animal studies show promising reductions in tumor growth.
Tumors often harbor immune cells called macrophages, which are equipped to attack cancer but are typically suppressed by the tumor's environment. A team at KAIST, led by Professor Ji-Ho Park from the Department of Bio and Brain Engineering, has devised a strategy to reactivate these cells on-site. Announced on December 30, the breakthrough involves injecting a specially designed drug that macrophages absorb readily.
The drug consists of lipid nanoparticles delivering mRNA encoding chimeric antigen receptor (CAR) proteins—devices that enable cells to recognize and target cancer—along with an immune-boosting compound. Once absorbed, the macrophages produce these CAR proteins themselves, evolving into what the researchers call "CAR-macrophages." These enhanced cells not only engulf cancer cells directly but also rally nearby immune responses, amplifying the overall anticancer effect.
Solid tumors, such as those in gastric, lung, and liver cancers, pose unique challenges due to their dense structure, which hinders immune cell infiltration and function. Existing CAR-macrophage therapies require extracting cells from patients, modifying them in labs, and reinfusing them—a process that is costly and logistically complex. The KAIST approach bypasses these steps by leveraging macrophages already present in the tumor microenvironment.
In experiments with animal models of melanoma, a severe form of skin cancer, the therapy significantly curbed tumor growth. Notably, the immune activation extended beyond the treated site, hinting at potential systemic benefits. Professor Ji-Ho Park emphasized the innovation: "This study presents a new concept of immune cell therapy that generates anticancer immune cells directly inside the patient's body." He added that it addresses key limitations of prior methods, including delivery efficiency and the suppressive tumor setting.
The research, with Jun-Hee Han as first author, appeared in the journal ACS Nano in 2025. Supported by Korea's National Research Foundation, it underscores advances in in situ immunotherapy.
