921 Hybrid lipid nanoparticles enable in situ and ex vivo dendritic cell-based cancer immunotherapy
Year: 2026
Type: conference-abstract
Abstract: Background Dendritic cells are central to initiating antitumor immunity, but their therapeutic activation requires coordinated stimulation of multiple intracellular pathways. 1 We developed complementary LNP-based strategies to engineer DC function in situ and ex vivo.2 For in situ activation, a hybrid ‘nanoparticle-in-nanoparticle’ LNP co-delivered poly I:C to activate TLR3 and LCL-161-loaded cyclodextrin nanoparticles to stimulate noncanonical NF-κB signaling. We then extended this approach to ex vivo LNP-mRNA engineering of DCs, enabling controlled antigen delivery and cellular activation while limiting systemic exposure (figure 1).Methods Hybrid LNPs composed of C12-200, DSPC, cholesterol, and DMG-PEG2000 were generated by microfluidic mixing. LCL-161-loaded lipophilic CDNPs and poly I:C were incorporated into the aqueous and organic phases, respectively to formulate LNPs. Formulations were characterized for size, surface charge, and encapsulation efficacy. Immune activity was evaluated in IL-12-eYFP reporter bone marrow-derived DCs. Fluorescent LNPs were used to assess circulation, tumor accumulation, cellular uptake, and IL-12 induction by intravital imaging in MC38 tumors. Antitumor efficacy, survival, rechallenge protection, and intratumoral DC and CD8 + T-cell infiltration were evaluated after systemic administration. Separately, BMDCs were engineered ex vivo with OVA mRNA-LNPs, characterized for activation and antigen presentation, and adoptively transferred before B16-OVA challenge.Results The optimized LNP17 formulation was approximately 120 nm and contained an internal CDNP (~38 nm). It achieved approximately 75% poly I:C encapsulation and 18.6% CDNP incorporation and induced higher IL-12 levels than single-payload controls. LNP17 exhibited a vascular half-life of approximately 30 minutes, with maximal intratumoral IL-12 induction at 72 hours. A single intravenous dose of the hybrid LNPs reduced MC38 tumor volume by approximately 30% within 24 hours and 80% within 48 hours. Tumors were eradicated by day 18, yielding 100% long-term survival ( figure 1) and complete protection after rechallenge two months later. Histology showed increased CD11c+ DCs and CD8+ T-cell infiltration. Ex vivo OVA mRNA-LNP treatment activated approximately 75% of DCs, enhanced antigen presentation and costimulatory markers, stimulated OT-I proliferation, and delayed B16-OVA tumor appearance by one week.Conclusions These studies establish LNP-mediated DC engineering as a versatile strategy for cancer immunotherapy. Hybrid LNPs coordinated complementary innate immune pathways to activate endogenous DCs and generate potent systemic antitumor responses, while ex vivo LNP-mRNA engineering produced activated, antigen-presenting DC vaccines with greater control over cellular programming and systemic exposure. Together, these complementary in situ and ex vivo approaches enhanced DC-mediated T-cell immunity, improved tumor control, and generated durable systemic immune memory.References Das R, Ge X, Fei F, Weissleder R, Garris CS. Lipid Nanoparticle-mRNA Engineered DC Adoptive Cell Therapy Enhances Cancer Immune Response. Small Methods 2024;24–33.Das R, Halabi EA, Fredrich IR, Oh J, Peterson HM, Ge X, Scott E, Kohler R, Garris CS, Weissleder R. Hybrid LNP Prime Dendritic Cells for Nucleotide Delivery. Adv Sci. 2023;23–35.Abstract 921 Figure 1Complementary In situ and ex vivo dendritic cell engineering strategies for cancer immunotherapy. In situ immunostimulatory LNPs activated endogenous dendritic cells and achieved complete survival in MC38 tumors, while ex vivo LNP-mRNA-engineered dendritic cells improved survival following B16-OVA challenge
Language: English
Subfield: Immunology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $2,490
OpenAlex ID: W7225150911