Nano STING Agonist Inhibits Brain Metastases of Solid Tumors through Synergistic Chemotherapy, STING Activation, and...

Area of Science:

• Oncology
• Nanotechnology
• Immunotherapy

Background:

• Brain metastases (BrM) are a severe complication of solid tumors with poor outcomes.
• The blood-brain barrier and immunosuppressive tumor microenvironment (TME) limit treatment efficacy.
• Stimulator of Interferon Genes (STING) pathway activation is a promising immunotherapy, but faces challenges in clinical application.

Purpose of the Study:

• To develop a dual-responsive nanosystem for targeted co-delivery of STING agonist (diABZI) and paclitaxel (PTX) to brain metastases.
• To overcome limitations of systemic toxicity, tumor selectivity, and intracranial delivery for STING-based therapies.
• To establish a synergistic therapeutic strategy for solid tumor BrM by combining direct tumor cell killing and immune system activation.

Main Methods:

• Development of a composite nanosystem, (PC-A)/M nanoparticles, for co-delivery of diABZI and PTX.
• Utilized a dual-responsive mechanism (pH and glutathione-GSH) for controlled nanoparticle dissociation and cargo release within the TME and cancer cells.
• Evaluated the synergistic effects of PTX-induced immunogenic cell death and STING activation on tumor vasculature, immune cell reprogramming, and anti-tumor response.

Main Results:

• The dual-responsive nanoparticles successfully delivered both STING agonist and paclitaxel.
• The nanosystem demonstrated enhanced cellular uptake and triggered cargo release in acidic and GSH-rich environments.
• The combined therapy reprogrammed the tumor immune microenvironment, promoting dendritic cell maturation, M1 macrophage polarization, and cytotoxic T-cell infiltration.
• The strategy showed potential for targeting both primary tumors and brain metastases, inducing a durable anti-tumor immune response.

Conclusions:

• The developed (PC-A)/M nanoparticle system offers a promising strategy for overcoming challenges in treating brain metastases.
• Targeted co-delivery of STING agonist and paclitaxel synergistically enhances anti-tumor immunity and efficacy.
• This approach holds potential as a novel therapeutic modality for solid tumor brain metastases.