Authors:	Schunke, Jenny
Title:	Adjuvant-loaded protein-based nanocapsules induce effective anti-cancer immunity
Online publication date:	4-Jan-2024
Year of first publication:	2024
Language:	english
Abstract:	Nanocarrier-based vaccines enable the simultaneous transport of antigens and adjuvants for specific activation of the immune system for cancer therapy. In this context, the targeting of dendritic cells (DCs), whose maturation can be induced and directed by specific adjuvants and which can prime naϊve T cells in an antigen-specific manner, is particularly relevant. Within the scope of this PhD project, protein-based nanocapsules with a shell/core morphology were evaluated. Human serum albumin (HSA) and ovalbumin (OVA) with high biocompatibility, degradability, and low cytotoxicity were used as shell materials. Combinatorial encapsulation of multiple adjuvants, which stimulate different signaling pathways, into the aqueous capsule core was successfully established. The uptake of HSA capsules loaded with the adjuvants muramyl dipeptide (MDP), resiquimod (R848) and polyinosinic:polycytidylic acid (Poly(I:C)) by dendritic cells and the subsequent DC maturation were demonstrated. Additionally, it could be shown that the combination of adjuvants in particular is necessary to sufficiently stimulate DCs. Flow cytometric analyses were performed to evaluate the expression of costimulatory molecules and the secretion of pro-inflammatory cytokines and chemokines. OVA-NCs allowed the simultaneous transport of the model antigen with the adjuvants MDP, R848, and Poly(I:C) to dendritic cells. Effective OVA peptide presentation to naïve T cells via loading on MHC class I and MHC class II molecules inducing T cell proliferation could be demonstrated in vitro. Subsequently, the potential of adjuvant-loaded OVA nanocapsules to induce anti-tumor immune responses was evaluated in a murine melanoma model. For this purpose, C57BL/6J mice were injected with OVA-expressing B16/F10 melanoma cells and subsequently treated with different OVA-NC formulations. Significant reduction of tumor growth, in particular by combined encapsulating of R848 and MDP, was obtained. Furthermore, it could be shown that only the transport of antigen and adjuvants in nanocapsules to DCs induced an efficient anti-tumor immune response, whereas the administration of soluble adjuvants and antigens did not achieve comparable results. Through a comparative study including different NC amounts and injection routes, the optimal therapeutic regimen was established. To induce complete tumor remission, R848, a Toll-like receptor 7/8 agonist, was encapsulated in combination with the potent STING agonist diamidobenzimidazole (diABZI, compound 3), in OVA nanocapsules. This adjuvant combination induced synergistic effects in vitro with respect to the expression of DC maturation markers as well as the production of a broad spectrum of pro-inflammatory cytokines and chemokines. In particular, the induction of type I interferons, which are required for an efficient anti-tumor immune response, by diABZI offered an advantage over the previously established adjuvant combination. In subsequent tumor studies, animals with OVA-expressing B16/F10 melanomas were cured by triple injection of diABZI- and R848/diABZI-loaded nanocapsules. The nanovaccine was evolved by supplemental encapsulation of the melanoma-specific antigen tyrosinase-related protein 2 (TRP2). This melanoma-specific nanovaccine elicited a significant reduction of wild-type B16/F10 melanomas. Another focus was set on the characterization of the NC-induced immune response. The infiltration of different immune cells into tumor-draining lymph nodes and the tumor tissue in vivo was demonstrated. In particular, the anti-tumor immune response was shown to be mediated by antigen-specific activation of CD8+ cytotoxic T cells. In addition, the effect of NC treatment on the expression of immune checkpoint receptors by CD8+ T cells was investigated. The nanoparticle-based tumor vaccine presented in this PhD thesis can be flexibly adapted for personalized cancer therapies by encapsulation of patient-specific peptides and further modified with immune cell-addressing molecules.
DDC:	570 Biowissenschaften 570 Life sciences
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 10 Biologie
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-9776
URN:	urn:nbn:de:hebis:77-openscience-4c3b808c-127b-4070-b250-cf9eb8e3780b1
Version:	Original work
Publication type:	Dissertation
License:	In Copyright
Information on rights of use:	http://rightsstatements.org/vocab/InC/1.0/
Extent:	XI, 116 Seiten ; Illustrationen, Diagramme
Appears in collections:	JGU-Publikationen