Endoplasmic Reticulum‐Targeting Self‐Assembly Nanosheets Promote Autophagy and Regulate Immunosuppressive Tumor Microenvironment for Efficient Photodynamic Immunotherapy

Abstract The poor efficiency and low immunogenicity of photodynamic therapy (PDT), and the immunosuppressive tumor microenvironment (ITM) lead to tumor recurrence and metastasis. In this work, TCPP‐T ER ‐Zn@RSV nanosheets (TZR NSs) that co‐assembled from the endoplasmic reticulum (ER)‐targeting photosensitizer TCPP‐T ER ‐Zn nanosheets (TZ NSs for short) and the autophagy promoting and indoleamine‐(2, 3)‐dioxygenase (IDO) inhibitor‐like resveratrol (RSV) are fabricated to enhance antitumor PDT. TZR NSs exhibit improved therapeutic efficiency and amplified immunogenic cancer cell death (ICD) by ER targeting PDT and ER autophagy promotion. TZR NSs reversed the ITM with an increase of CD8+ T cells and reduce of immunosuppressive Foxp3 regulatory T cells, which effectively burst antitumor immunity thus clearing residual tumor cells. The ER‐targeting TZR NSs developed in this paper presents a simple but valuable reference for high‐efficiency tumor photodynamic immunotherapy.