A Nanotherapeutic Strategy to Reverse NK Cell Exhaustion

Area of Science:

• Immunology
• Nanotechnology
• Oncology

Background:

• Natural killer (NK) cells are crucial for immunotherapy but are often weakened by tumor immunosuppression and exhaustion.
• Cancer cells can express abnormal factors that inhibit NK cell function, limiting therapeutic efficacy.

Purpose of the Study:

• To develop a novel nanoparticle-based strategy to reverse NK cell exhaustion and enhance cancer immunotherapy.
• To investigate the mechanism by which selenium nanoparticles can restore NK cell activity against tumors.

Main Methods:

• Self-assembled selenium-containing nanoparticles (NPs) were engineered using cetuximab, C5SeSeC5, and the inhibitor LY345899.
• NPs were designed to target epidermal growth factor receptor on cancer cells and deliver LY345899 to mitochondria.
• The study assessed the impact of LY345899-induced reactive oxygen species and seleninic acid formation on human leukocyte antigen E expression and NK cell inhibition.

Main Results:

• The developed NPs successfully targeted cancer cells and mitochondria, releasing LY345899 to inhibit methylene tetrahydrofolate dehydrogenase 2.
• This inhibition led to increased reactive oxygen species, seleninic acid formation, and reduced human leukocyte antigen E expression, thereby overcoming NKG2A-mediated NK cell inhibition.
• Combined cetuximab and NP treatment effectively inhibited xenograft tumor growth and induced an abscopal effect on distant tumors.

Conclusions:

• The combination of seleninic acid, LY345899, and cetuximab offers a promising new strategy for reversing NK cell exhaustion.
• This approach holds significant potential for treating metastatic tumors by enhancing NK cell-mediated immunotherapy and antibody-dependent cell-mediated cytotoxicity.