Adoptive transfer of FeO-SWCNT engineered M1-like macrophages for magnetic resonance imaging and enhanced cancer immunotherapy.

Macrophage-based tumor immunotherapy can effectively kill tumor cells in a direct manner when tumor specific antigens are idle or unknown. However, the presence of M2-like tumor associated macrophages (TAMs) would limit the treatment efficiency. Therefore, reversing the M2-like TAMs phenotype to regulate the immunosuppressive tumor microenvironment (TME) is crucial. Herein, we proposed nano-sized ferroferric oxide/single wall carbon nanotubes composites (FeO-SWCNT) to engineer the macrophages species for powerful cancer therapy. The synthesized FeO-SWCNT revealed good magnetic resonance imaging (MRI) performance, which enabled in vivo tracking of macrophage mediated immunotherapy. In addition, FeO-SWCNT engineered M1-like macrophages (FeO-SWCNT@M1) could maintain M1 phenotype, migrate to tumor cells and release nitric oxide (NO), reactive oxygen species (ROS) and tumor necrosis factor-α (TNF-α). A series of experimental results showed that FeO-SWCNT@M1 could effectively promote the polarization of endogenous M2-like macrophages to M1-like macrophages, activate tumor immune response and inhibit tumor progression. This work is expected to provide a new vision for macrophage-based tumor immunotherapy.