Reshaping immune cell distribution with mRNA noncationic lipid nanoparticles for overcoming neoadjuvant chemo-immunotherapy resistance.

RATIONALE: Fusobacterium nucleatum (Fn) is associated with resistance to neoadjuvant chemo-immunotherapy in esophageal squamous cell carcinoma (ESCC), but the underlying mechanism is unclear. We identified Fn-induced SPP1⁺ macrophages as key drivers of a cancer-associated fibroblast (CAF)-mediated spatial immune barrier that restricts CD8⁺ T-cell infiltration.

METHODS

Mannose-modified non-cationic thiourea lipid nanoparticles (NC-TNPM) were engineered to deliver Cas9 mRNA and SPP1-targeting sgRNA to macrophages. Their therapeutic efficacy was evaluated in Fn-associated ESCC models combined with chemotherapy and anti-PD-L1 treatment.

RESULTS

NC-TNPM achieved efficient SPP1 silencing, markedly reduced SPP1⁺ macrophages, disrupted the macrophage-CAF immune barrier, and restored intratumoral CD8⁺ T-cell infiltration. Combined with chemo-immunotherapy, NC-TNPM significantly suppressed tumor growth, enhanced cytotoxic T-cell activity, promoted macrophage repolarization, and showed no evident toxicity.

CONCLUSIONS

Fn-induced SPP1⁺ macrophages drive immune exclusion and chemo-immunotherapy resistance in ESCC. Macrophage-targeted SPP1 editing with NC-TNPM overcomes this barrier and enhances therapeutic efficacy, highlighting a promising nanomedicine strategy for ESCC.