Abstract 6745: Crafting hyaluronic acid-based nanoparticles for enhanced LN targeting as a potent priming tool in immunotherapy

Abstract Background: Cholesterol-conjugated hyaluronic acid, synthesized by grafting cholesterol moieties onto hyaluronic acid, spontaneously formed nano-sized hydrogel of approximately 30-100nm in water. This hyaluronic acid derivative (HA nanogel) has demonstrated the ability to encapsulate various modalities, including low- and medium-sized molecules, peptides, and proteins. Previous reports have highlighted its efficacy in solubilizing poorly water-soluble drugs and serving as a sustained-release matrix. In this study, we explore the potential of HA nanogels encapsulating antigen peptides with adjuvant as a cancer vaccine and a priming tool for combinational immunotherapy. Method: We prepared HA nanogels as a novel peptide carrier for cancer vaccines and attempted to encapsulate various peptides, including neoantigen (mERK2) peptides expressed in immune checkpoint inhibitor (ICI) therapy-resistant fibrosarcoma cell line CMS5a, gp-100 peptides expressed in metastatic melanoma cell line B16F10, and MAGEA4. Our experiments covered APC uptake, antigen-specific CTL induction, and anti-tumor studies to demonstrate the utility of HA nanogels in these applications. Results: HA nanogel efficiently formed stable complexes with mERK2, gp-100 and MAGEA4 long peptides, each with diameters of 30-100nm. The facile and simple vaccine formulation processes with HA nanogel achieved high drug content and high encapsulation efficiency of 90% or higher. Fluorescently labeled mERK2 long peptide encapsulated in HA nanogel vaccines were subcutaneously administered to BALB/c mice, and uptake analysis of mERK2 long peptides in draining lymph nodes (dLN) was performed using flow cytometry. In comparison to the group receiving mERK2 long peptide without nanogel encapsulation, the HA nanogel group exhibited higher uptake by macrophages and dendritic cells in the dLN. Administering HA nanogel vaccines containing mERK2 long peptides with CpG oligoDNA resulted in higher antigen-specific CD8+ T cells compared to the group receiving mERK2 long peptides without encapsulation. Strong anti-tumor effects were demonstrated in mice models with subcutaneously transplanted CMS5a and B16F10 cell lines. The enhanced efficacy through co-administration with ICI was also confirmed. Conclusion: HA nanogel vaccines efficiently deliver antigen peptides to macrophages and dendritic cells, inducing antigen-specific CTL responses, thereby demonstrating anti-tumor effects against cold tumors such as CMS5a and B16F10. HA nanogels have the potential not only as carriers for cancer vaccines but also as priming tools for combinational immunotherapy. Citation Format: Takashi Nakai, Fumiyasu Momose, Kohei Yabuuchi, Makiko Yamane, Tae Hayashi, Linan Wang, Yoshiyuki Nakagawa, Shogo Aso, Toru Katsumata, Tsuyoshi Shimoboji, Yoshihiro Miyahara. Crafting hyaluronic acid-based nanoparticles for enhanced LN targeting as a potent priming tool in immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6745.