Multi-Functional AIE Phototheranostic Agent Enhancing αPD-L1 Response for Oral Squamous Cell Carcinoma Immunotherapy

Oral squamous cell carcinoma (OSCC) represents a prevalent head and neck malignancy with surgical intervention as the primary clinical option. Immunotherapy, particularly immune checkpoint blockade (ICB) targeting PD-1/PD-L1 shows great promise but is impeded by the immunosuppressive tumor microenvironment and low PD-L1 expression in OSCC. Herein, the "all-in-one" phototherapeutic nanoparticles (TSD NPs) are reported with balanced reactive oxygen species and photothermal conversion capacity for combined photoimmunotherapy and ICB immunotherapy against OSCC. A novel electron acceptor, 3-(dicyanomethylene)-2,3-dihydrobenzothiophene-1,1-dioxide (DTM), is introduced to develop the phototherapeutic agent with aggregation-induced emission (AIE) feature and NIR-II fluorescence centered at 1000 nm. Benefiting from the AIE feature and the DTM acceptor, the resultant TSD NPs also exhibit strong type I reactive oxygen species (ROS) generation and high photothermal conversion efficiency (45.3%), which can profoundly induce immunogenic cell death (ICD), activate cytotoxic T lymphocytes, and convert the immunosuppressive tumor microenvironment into an immune-supportive one. Additionally, TSD NPs upregulate the PD-L1 expression on OSCC cells, thus enhancing the efficacy of combined treatment with αPD-L1 ICB immunotherapy. This results show that the synergistic treatment of TSD NPs and αPD-L1 effectively eradicates solid OSCC tumors without adverse effects on normal tissues, proving a novel and promising strategy for OSCC management.