Nanoparticle Retinoic Acid-Inducible Gene I Agonist for Cancer Immunotherapy

Area of Science:

• Immunology
• Nanomedicine
• RNA Therapeutics

Background:

• The retinoic acid-inducible gene I (RIG-I) pathway is a promising target for cancer immunotherapy.
• Current RIG-I agonists face challenges like poor pharmacokinetics and inefficient delivery.

Purpose of the Study:

• To develop novel ionizable lipid nanoparticles (LNPs) for effective delivery of 5'-triphosphate RNA (3pRNA) stem-loop RNAs (SLRs) to activate RIG-I.
• To evaluate the therapeutic potential of these SLR-loaded LNPs (SLR-LNPs) in enhancing anti-tumor immunity and response to immune checkpoint inhibitors (ICIs).

Main Methods:

• Designed and characterized SLR-LNPs for surface charge-neutrality and optimal size (~100 nm).
• Assessed RIG-I activation in vitro and in vivo following SLR-LNP administration.
• Evaluated SLR-LNP efficacy in preclinical models of melanoma and triple-negative breast cancer, including combination therapy with ICIs.

Main Results:

• SLR-LNPs demonstrated safe administration and potent RIG-I activation in the tumor microenvironment (TME).
• SLR-LNPs inhibited tumor growth and enhanced CD8+ and CD4+ T cell infiltration in breast cancer models.
• Systemic SLR-LNP administration reduced lung metastatic burden in melanoma models, outperforming combination ICI therapy.

Conclusions:

• SLR-LNPs represent a translationally viable nanomedicine for potent RIG-I activation.
• This platform enhances anti-tumor immunity and holds significant potential for improving ICI efficacy and other immunotherapies.