NIR-715 photodynamic therapy induces immunogenic cancer cell death by enhancing the endoplasmic reticulum stress response.

Abstract

Effectively interfering with endoplasmic reticulum (ER) function in tumor cells and simultaneously activating an anti-tumor immune microenvironment to attack the tumor cells are promising strategies for cancer treatment. However, precise ER-stress induction is still a huge challenge. In this study, we synthesized a near-infrared (NIR) probe, NIR-715, which induces tumor cell death and inhibits tumor growth without causing apparent side effects. NIR-715 triggers severe ER stress and immunogenic cell death (ICD) after visible light exposure. NIR-715 induced ICD-associated HMGB1 release in vitro and anti-tumor immune responses, including increased cytotoxic T lymphocyte (GZMB⁺ CD8⁺ T cell) infiltration and decreased numbers of exhausted T lymphocytes (PD-L1⁺ CD8⁺ T cell). These findings suggest that NIR-715 may be a novel agent for "cold" tumor photodynamic therapy (PDT). Schematic illustration of NIR-715 photodynamic therapy for visible light-triggered, endoplasmic reticulum-targeting antitumor therapy.