Photodynamic Therapy-Induced Anti-Tumor Immunity: Influence Factors and Synergistic Enhancement Strategies

Abstract

Photodynamic therapy (PDT) is an approved therapeutic procedure that exerts cytotoxic activity towards tumor cells by activating photosensitizers (PSs) with light exposure to produce reactive oxygen species (ROS). Compared to traditional treatment strategies such as surgery, chemotherapy, and radiation therapy, PDT not only kills the primary tumors, but also effectively suppresses metastatic tumors by activating the immune response. However, the anti-tumor immune effects induced by PDT are influenced by several factors, including the localization of PSs in cells, PSs concentration, fluence rate of light, oxygen concentration, and the integrity of immune function. In this review, we systematically summarize the influence factors of anti-tumor immune effects mediated by PDT. Furthermore, an update on the combination of PDT and other immunotherapy strategies are provided. Finally, the future directions and challenges of anti-tumor immunity induced by PDT are discussed.

Advances in Nanodynamic Therapy for Cancer Treatment

“…This interaction predominantly results in the generation of 1 O 2 and other ROS, initiating a cascade of oxidative damage within the cell. Subsequently, it impairs the tumor vascular network by initiating the release of vasoconstrictive agents and promoting thrombus formation [51]. Zheng et al synthesized a highly cationic zinc phthalocyanine (Pc4) with exceptional water solubility and non-aggregating properties, which maintained high photodynamic activity in biological systems.…”

Use of photosensitive molecules in the crosslinking of biopolymers: applications and considerations in biomaterials development

“…Photosensitizers that act predominantly via an electron/proton transfer mechanism promote the generation of reactive species independently of O 2 presence; due to this, this type of PSs can be suited for hypoxic environments, where the O 2 consumption can be an undesired side effect, as in tumor's environments. 147 In comparison, type II photosensitized oxidation PSs act in the presence of O 2 to produce 1 O 2 , offering a more controlled approach in well-oxygenated tissues but may cause or aggravate detrimental hypoxia conditions. 148…”