Nanoparticles Boost Efficacy Of Cancer Immunotherapy

Researchers in China have developed antibody nanoparticles that boost antitumor immunity in mice.

AsianScientist (Aug. 1, 2019) – Immune checkpoint blockade has emerged as one of the most promising treatments for cancer in recent years. Now, scientists in China want to augment cancer immunotherapy with nanoparticles. Their approach is published in the journal Science Immunology.

The immune system typically polices the body and destroys cells that fail to divide normally or are damaged by environmental insults. However, cancer cells survive immune surveillance using the programmed cell death ligand 1 (PDL1), a protein that inhibits immune cell activity in the vicinity of a tumor. Scientists have recently found a way to restore the antitumor function of immune cells using antibodies that bind to PDL (αPDL1). However, not all patients respond to αPDL1 treatment.

To raise the efficacy of αPDL1 therapy, researchers led by Professors Yu Haijun and Li Yaping at the Shanghai Institute of Materia Medica of the Chinese Academy of Sciences attached antibodies to nanoparticles containing indocyanine green (ICG). ICG is a clinically approved fluorophore for imaging in live surgery, and a photosensitizer for photodynamic therapy.

The researchers demonstrated that their antibody nanoparticles remained inert during blood circulation, and αPDL1 was prevented from binding with normal tissues. When the antibody nanoparticles accumulate at the tumor site, however, they become activated and release αPDL1, in turn triggering the release of tumor antigens and promoting infiltration of cytotoxic T lymphocytes.

The team’s approach not only boosted antitumor immunity with great efficiency, but also elicited long-term immune memory effects in a mouse model of cancer, thus leading to tumor regression. Tumor metastasis to the lung was also effectively suppressed, which resulted in more than 70 percent of tumor-bearing mice surviving for more than 65 days.

“Given the simplicity of the nanostructures, our study has the potential of being translated into future generations of cancer immunotherapy,” said Yu.

The article can be found at: Wang et al. (2019) Engineering Nanoparticles to Locally Activate T Cells in the Tumor Microenvironment.


Source: Chinese Academy of Sciences; Photo: Wang Dangge.
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