Abstract

The alternations in the hypoxic and immune microenvironment are closely related to the therapeutic effect and prognosis of oral squamous cell carcinoma (OSCC). Herein, a new nanocomposite, TiO 2 @ [email protected] is constructed from a ruthenium-based photosensitizer ( Ru ) modified- TiO 2 nanoparticles (NPs) loaded with siRNA of hypoxia-inducible factor-1α (HIF-1α). Under visible light irradiation, TiO 2 @ [email protected] can elicit both Type I and Type II photodynamic effects, which causes lysosomal damage, HIF-1α gene silencing, and OSCC cell elimination efficiently. As a consequence of hypoxia relief and pyroptosis induction, TiO 2 @ [email protected] reshapes the immune microenvironment by downregulation of key immunosuppressive factors, upregulation of immune cytokines, and activation of CD4 + and CD8 + T lymphocytes. Furthermore, patient-derived xenograft (PDX) and rat oral experimental carcinogenesis models prove that TiO 2 @ [email protected] -mediated photodynamic therapy significantly inhibits the tumor growth and progression, and markedly enhances cancer immunity. In all, this study presents an effective hypoxia-adaptive photo-immunotherapeutic nanosystem with great potential for OSCC prevention and treatment.