Biodegradable lipophilic polymeric mRNA nanoparticles for ligand-free targeting of splenic dendritic cells for cancer vaccination

Nanoparticle (NP) -based mRNA cancer vaccines hold great promise to realize person-alized cancer treatments. To advance this technology requires delivery formulations for efficient intracellular delivery to antigen-presenting cells. We developed a class of bioreducible lipophilic poly(beta- amino ester) nanocarriers with quadpolymer architec-ture. The platform is agnostic to the mRNA sequence, with one -step self-assembly allow-ing for delivery of multiple antigen-encoding mRNAs as well as codelivery of nucleic acid-based adjuvants. We examined structure-function relationships for NP-mediated mRNA delivery to dendritic cells (DCs) and identified that a lipid subunit of the pol-ymer structure was critical. Following intravenous administration, the engineered NP design facilitated targeted delivery to the spleen and preferential transfection of DCs without the need for surface functionalization with targeting ligands. Treatment with engineered NPs codelivering antigen-encoding mRNA and toll -like receptor agonist adjuvants led to robust antigen-specific CD8+ T cell responses, resulting in efficient antitumor therapy in in vivo models of murine melanoma and colon adenocarcinoma.