Engineering nanoparticles to locally activate T cells in the tumor microenvironment

Area of Science:

• Immunology
• Nanotechnology
• Oncology

Background:

• Tumor immunological tolerance hinders effective anti-cancer immunity, characterized by low cytotoxic T lymphocyte (CTL) infiltration and an immunosuppressive tumor microenvironment.
• Tumor resistance to immune checkpoint inhibitors (ICIs) remains a significant challenge in current cancer immunotherapy, particularly immune checkpoint blockade (ICB) therapy.

Purpose of the Study:

• To develop tumor microenvironment-activatable anti-PDL1 antibody nanoparticles for combination immunotherapy.
• To overcome tumor immunological tolerance and enhance the efficacy of ICB therapy.

Main Methods:

• Development of anti-PDL1 antibody (αPDL1) nanoparticles activated within the tumor microenvironment.
• Combination therapy involving αPDL1 nanoparticles and near-infrared (NIR) laser irradiation activating indocyanine green.
• Assessment of reactive oxygen species (ROS) generation, CTL infiltration, tumor growth, and metastasis in mouse models.

Main Results:

• The combination therapy induced ROS generation, promoting intratumoral CTL infiltration.
• This approach sensitized tumors to PDL1 blockade therapy, effectively suppressing tumor growth.
• Significant reduction in lung and lymph node metastasis was observed in treated mouse models.

Conclusions:

• Tumor microenvironment-activatable αPDL1 nanoparticles combined with NIR laser irradiation offer a promising strategy to overcome tumor immune tolerance.
• This nanoplatform enhances anti-tumor immunity and ICB therapy efficacy.
• The adaptable nanoplatform design can be readily applied to other immune checkpoint inhibitors for improved cancer immunotherapy.