Combination of MHI148 Targeted Photodynamic Therapy and STING Activation Inhibits Tumor Metastasis and Recurrence

Area of Science:

• Oncology
• Immunology
• Nanotechnology
• Biomedical Engineering

Background:

• Breast cancer metastasis and recurrence significantly contribute to mortality.
• Current immunotherapies face challenges including impaired dendritic cell (DC) function and poor T cell infiltration.
• Effective strategies are needed to overcome these limitations and improve treatment outcomes.

Purpose of the Study:

• To develop a multifunctional nanoparticle platform (GM@P) for enhanced breast cancer immunotherapy.
• To combine photodynamic therapy (PDT) and STING activation for synergistic antitumor effects.
• To investigate the platform's ability to improve antigen presentation, T cell infiltration, and reduce metastasis and recurrence.

Main Methods:

• Developed GM@P nanoparticles encapsulating photosensitizer MHI148 and STING agonist 2'3'-cGAMP.
• Utilized 808 nm laser irradiation for PDT-induced cancer cell death and immunogenic cell death (ICD).
• Employed photoacoustic imaging (PAI) for simultaneous diagnosis and therapy monitoring.

Main Results:

• GM@P nanoparticles targeted breast cancer cells and generated reactive oxygen species (ROS) upon laser irradiation.
• PDT induced ICD, enhancing antitumor immunity.
• Combined PDT and STING activation promoted DC maturation, CD8+ T cell infiltration, and cytokine release, creating a favorable immune microenvironment.
• Demonstrated suppression of tumor growth, inhibition of metastasis, and prevention of recurrence.

Conclusions:

• The multifunctional nanoparticle platform (GM@P) effectively combines PDT and STING activation for potent breast cancer immunotherapy.
• This strategy overcomes key immunotherapy challenges, fostering robust local and systemic antitumor immune responses.
• The approach shows significant promise for preventing breast cancer recurrence and metastasis.