Designing Programmable Peptide Nucleic Acid‐based Nanovaccines for Anticancer Immune Activation

Abstract Targeted delivery of antigens and adjuvants to the immune cells without eliciting uncontrolled inflammation is a major challenge in cancer vaccine development. Here, a highly versatile and programmable peptide nucleic acid (PNA)‐based vaccine nanoplatform (PVN) is reported to elicit a robust anti‐tumor immune response against B16‐OVA syngeneic melanoma model. The PVN is built on an 11‐mer PNA scaffold, enabling efficient “one‐pot” loading of a PNA‐modified ovalbumin antigenic peptide (SIINFEKL), CpG adjuvant, and a PNA‐derivatized LLP2A ligand (an immune cell and melanoma cell targeting ligand). Super‐resolution fluorescence imaging reveals the spatial arrangement of OVA ₈ within LP _10‐12 [ OVA ₈ /CpG/LLP2A ], while circular dichroism spectroscopy confirmsparalleled binding of complementary PNA strands in LP ₁₁ [ OVA ₈ /CpG/LLP2A ]. LLP2A displayed on PVNs target activated α4β1 integrin expressed by immune and melanoma cells, boosting antigen presentation by dendritic cells and eliciting strong CD8+T cell and natural killer cell responses. This amplified antitumor immune response leads to significant tumor regression and prolonged survival of mice bearing syngeneic B16‐OVA melanoma. The modular nature and versatility of PVN allow convenient one‐pot assembling of peptide antigens, immunomodulators, immune cell and tumor cell targeting ligands, making it practical for the custom design and preparation of personalized cancer vaccines.