Activating the cGAS-STING Pathway by Manganese-Based Nanoparticles Combined with Platinum-Based Nanoparticles for Enhanced Ovarian Cancer Immunotherapy.

Recent research has demonstrated that activating the cGAS-STING pathway can enhance interferon production and the activation of T cells. A manganese complex, called TPA-Mn, was developed in this context. The reactive oxygen species (ROS)-sensitive nanoparticles (NPMn) loaded with TPA-Mn are developed. NPMn activates the cGAS-STING pathway via cGAS activation (i.e., 1.6-fold enhancement of P-STING), which in turn increases the secretion of pro-inflammatory cytokines (e.g., TNF-α, IL-6, and IL-2). This promotes dendritic cell maturation, enhances the infiltration of cytotoxic T lymphocytes, and reduces the percentage of immunosuppressive regulatory T cells. In addition, it is crucial to emphasize that cisplatin-induced DNA damage can potentially trigger activation of the cGAS-STING pathway. NPMn, in combination with low-dose NPPt, a carrier of a Cis(IV) prodrug capable of causing DNA damage, augments the cGAS-STING pathway activation and significantly activates the tumor immune microenvironment (TIME). Furthermore, combined with anti-PD-1 antibody, NPPt+NPMn shows synergistic efficacy in both ovarian cancer peritoneal metastases and recurrence models. It not only effectively eliminates tumors but also induces a strong immune memory response, providing a promising strategy for the clinical management of ovarian cancer. This work offers a design of manganese-based nanoparticles for immunotherapy.