Triplet RNA Lipid Nanoparticles for Locoregional Cancer Immunotherapy

Area of Science:

• Nanomedicine
• Immunotherapy
• RNA Therapeutics

Background:

• Ionizable lipid nanoparticles (LNPs) are established for nucleic acid delivery.
• Expanding LNP platforms for novel therapeutic payloads is crucial.

Purpose of the Study:

• To develop and evaluate LNPs for delivering immunostimulatory polyinosinic-polycytidylic acid (pIpC).
• To explore combination RNA therapies using pIpC-LNPs with mRNA and siRNA for enhanced cancer immunotherapy.

Main Methods:

• Incorporation of pIpC into LNPs with minimal protocol changes.
• Characterization of pIpC-loaded LNPs (pIpC-LNPs) for size and morphology.
• Intratumoral administration of pIpC-LNPs in a tumor model.
• Screening of T cell activation markers (OX40, CD27) and PD-L1 expression.
• Formulation and evaluation of combination therapies using pIpC-LNPs, mRNA (CD70, OX40L), and siRNA (PDL1).

Main Results:

• pIpC-LNPs were successfully formulated, spherical, and <200 nm in diameter.
• Intratumoral pIpC-LNPs demonstrated superior potency to soluble adjuvant, achieving 25% complete tumor remission.
• pIpC-LNP treatment upregulated OX40 and CD27, while PD-L1 was upregulated on cancer cells.
• Combination of pIpC-LNPs with siPDL1 resulted in significant tumor growth reduction.

Conclusions:

• pIpC-LNPs represent a potent intratumoral therapeutic strategy.
• The LNP platform facilitates a triplet RNA approach (immunostimulatory RNA, mRNA, siRNA) for cancer immunotherapy.
• OX40, CD27, and PD-L1 are identified as potential synergistic targets for LNP-based combination therapies.