Abstract
The clinical effectiveness of immunotherapies for lung cancers has been greatly hindered by the immune-excluded and immunosuppressive tumor microenvironment (TME) and limited pulmonary accessibility of therapeutics. Here, we develop an inhalable lipid nanoparticle (LNP) system that enables simultaneous delivery of mRNA encoding anti-discoidin domain receptor 1 (DDR1) single-chain variable fragments (mscFv) and siRNA targeting PD-L1 (siPD-L1) into pulmonary cancer cells. The secreted anti-DDR1 scFv blocks the binding of DDR1 extracellular domain to collagen, disrupting collagen fiber alignment and reducing tumor stiffness, thereby facilitating T cell infiltration. Meanwhile, PD-L1 silencing alleviates immunosuppression and preserves T cell cytotoxicity. In vivo results demonstrate that mscFv@LNP induces collagen fiber rearrangement and diminishes tumor stiffness. In both orthotopic and metastatic mouse models of lung cancer, inhalation of mscFv/siPD-L1@LNP promotes tumor regression and extends overall survival. This strategy could be broadly applicable to solid tumors and benefit other cancer immunotherapies by addressing the universally hostile TME involved in tumor progression.