KERS‐Inspired Nanostructured Mineral Coatings Boost IFN‐γ mRNA Therapeutic Index for Antitumor Immunotherapy

Abstract Tumor‐associated macrophage (TAM) reprogramming is a promising therapeutic approach for cancer immunotherapy; however, its efficacy remains modest due to the low bioactivity of the recombinant cytokines used for TAM reprogramming. mRNA therapeutics are capable of generating fully functional proteins for various therapeutic purposes but accused for its poor sustainability. Inspired by kinetic energy recovery systems (KERS) in hybrid vehicles, a cytokine efficacy recovery system (CERS) is designed to substantially augment the therapeutic index of mRNA‐based tumor immunotherapy via a “capture and stabilize” mechanism exerted by a nanostructured mineral coating carrying therapeutic cytokine mRNA. CERS remarkably recycles nearly 40% expressed cytokines by capturing them onto the mineral coating to extend its therapeutic timeframe, further polarizing the macrophages to strengthen their tumoricidal activity and activate adaptive immunity against tumors. Notably, interferon‐γ (IFN‐γ) produced by CERS exhibits ≈42‐fold higher biological activity than recombinant IFN‐γ, remarkably decreasing the required IFN‐γ dosage for TAM reprogramming. In tumor‐bearing mice, IFN‐γ cmRNA@CERS effectively polarizes TAMs to inhibit osteosarcoma progression. When combined with the PD‐L1 monoclonal antibody, IFN‐γ cmRNA@CERS significantly boosts antitumor immune responses, and substantially prevents malignant lung metastases. Thus, CERS‐mediated mRNA delivery represents a promising strategy to boost antitumor immunity for tumor treatment.