Dendritic Cell Targeting mRNA Lipopolyplexes Combine Strong Antitumor T-Cell Immunity with Improved Inflammatory Safety

Abstract

In vitro transcribed mRNA constitutes a versatile platform to encode antigens and to evoke CD8 T-cell responses. Systemic delivery of mRNA packaged into cationic liposomes (lipoplexes) has proven particularly powerful in achieving effective antitumor immunity in animal models. Yet, T-cell responses to mRNA lipoplexes critically depend on the induction of type I interferons (IFN), potent pro-inflammatory cytokines, which inflict dose-limiting toxicities. Here, we explored an advanced hybrid lipid polymer shell mRNA nanoparticle (lipopolyplex) endowed with a trimannose sugar tree as an alternative delivery vehicle for systemic mRNA vaccination. Like mRNA lipoplexes, mRNA lipopolyplexes were extremely effective in conferring antitumor T-cell immunity upon systemic administration. Conversely to mRNA lipoplexes, mRNA lipopolyplexes did not rely on type I IFN for effective T-cell immunity. This differential mode of action of mRNA lipopolyplexes enabled the incorporation of N1 methyl pseudouridine nucleoside modified mRNA to reduce inflammatory responses without hampering T-cell immunity. This feature was attributed to mRNA lipopolyplexes, as the incorporation of thus modified mRNA into lipoplexes resulted in strongly weakened T-cell immunity. Taken together, we have identified lipopolyplexes containing N1 methyl pseudouridine nucleoside modified mRNA as potent yet low-inflammatory alternatives to the mRNA lipoplexes currently explored in early phase clinical trials.

Advances in Lipid Nanoparticles for mRNA-Based Cancer Immunotherapy

“…Lipid-polymer hybrid nanoparticles, thanks to their structural design, can offer a series of benefits such as small size, high nucleic acid condensation efficiency, large functionalizable surface that can be easily modified by the binding of different functional groups, and prolonged blood circulation time (Guevara et al, 2019b). In addition, the specific physicochemical properties of hybrid lipid-polymer nanostructures can potentially result in a different interaction of the delivered mRNA with innate RNA sensors, consequently altering the immunogenicity and safety profile of lipopolyplex-based immunotherapies (Van der Jeught et al, 2018).…”

“…The above benefits of hybrid lipid-polymer formulations have been highlighted in a recent study were an mRNAloaded lipid-polymer platform functionalized with mannose receptor targeting moieties to promote dendritic cell (DC) targeting in vivo was employed (Van der Jeught et al, 2018). The formulation exhibited excellent hemocompatibility and the expression of the mRNA cargo was preferentially restricted to splenic antigen presenting cells (APCs) upon systemic administration.…”

“…The formulation exhibited excellent hemocompatibility and the expression of the mRNA cargo was preferentially restricted to splenic antigen presenting cells (APCs) upon systemic administration. Furthermore, vaccination with the lipopolyplex formulation elicited a potent T-cell-mediated immune response and manifested superior effectiveness in inhibiting tumor growth compared to intravenous immunization with a lipoplex-based mRNA vaccine (Van der Jeught et al, 2018). Early innate FIGURE 1 | Schematic representation of the different types of lipid-base nanovectors: lipoplex, lipid nanoparticle, lipid-polymer hybrid nanoparticle where the lipid shell can be organized as a bilayer or monolayer.…”

“…responses to hybrid lipid-polymer vaccine formulation were characterized by a type I interferon (IFN) response in the spleen. Nevertheless, unlike conventional lipoplexes, the hybrid lipidpolymer nanovaccine did not rely on type I IFN responses to generate cytotoxic T-cell effectors (Van der Jeught et al, 2018). This unlooked behavior of lipopolyplex nanostructures could enable the preparation of new anticancer therapeutic vaccines with a more moderate pro-inflammatory profile, but with an equal capacity to promote a potent immune response, representing a valid alternative to the lipid formulated mRNA vaccines currently under investigation in early phase clinical trials.…”

Bis‐Thioether‐Containing Lipid Chains in Cationic Amphiphiles: Physicochemical Properties and Applications in Gene Delivery

“…lamellar versus hexagonal). For nucleic acids delivery, cationic amphiphiles [2,13,14] were evaluated for different purposes (lung transfection, [15,16] tendon healing, [17] cancer therapy, [18] anticancer vaccination [19][20][21] ) and the current developments offer news therapeutic perspectives. It must be emphasized that one of the interest of synthetic vectors, when compared to viral vectors, is that they can be produced on large scale and following simple purification processes.…”