Immunomodulatory-Photodynamic Nanostimulators for Invoking Pyroptosis to Augment Tumor Immunotherapy.

Cancer immunotherapy is restricted to immune resistance caused by immunosuppressive tumor microenvironment. Pyroptosis involved in antitumor immunotherapy as a new schedule is prospective to reverse immunosuppression. Herein, acidic tumor microenvironment (TME)-evoked MRC nanoparticles (MRC NPs) co-delivering immune agonist RGX-104 and photosensitizer chlorine e6 (Ce6) are reported for pyroptosis-mediated immunotherapy. RGX-104 remodels TME by transcriptional activation of ApoE to regress myeloid-derived suppressor cells' (MDSCs) activity, which neatly creates foreshadowing for intensifying pyroptosis. Considering Ce6-triggered photodynamic therapy (PDT) can strengthen oxidative stress and organelles destruction to increase immunogenicity, immunomodulatory-photodynamic MRC nanodrugs will implement an aforementioned two-pronged strategy to enhance gasdermin E (GSDME)-dependent pyroptosis. RNA-seq analysis of MRC at the cellular level is introduced to first elucidate the intimate relationship between RGX-104 acting on LXR/ApoE axis and pyroptosis, where RGX-104 provides the prerequisite for pyroptosis participating in antitumor therapy. Briefly, MRC with favorable biocompatibility tackles the obstacle of hydrophobic drugs delivery, and becomes a powerful pyroptosis inducer to reinforce immune efficacy. MRC-elicited pyroptosis in combination with anti-PD-1 blockade therapy boosts immune response in solid tumors, successfully arresting invasive metastasis and extending survival based on remarkable antitumor immunity. MRC may initiate a new window for immuno-photo pyroptosis stimulators augmenting pyroptosis-based immunotherapy.