The use of mRNA therapies has innovated the clinical progress of cancer immunotherapy. However, current immunotherapeutic approaches are unable to achieve site- or immune-cell-specific delivery, resulting in adverse immune responses in off-target tissues. In addition, the commercial lipid nanoparticle (LNP) formulations with a poly(ethylene glycol) coating generally undergo significant hepatic accumulation during clearance. To promote site- and immune-cell-specific delivery of therapeutic mRNA-LNPs, we investigated several bioconjugation approaches to attach targeting antibodies onto the surface of polymer-functionalized mRNA-LNPs. Building on our previous work, side-chain sulfoxide polymer-lipid conjugate PMSEA-DSPE was used to incorporate a low-fouling polymeric LNP coating. trans-Cyclooctene functionality was incorporated within PMSEA-DSPE end groups to allow conjugation to the tetrazine-functionalized nanobody 9G8 for EGFR targeting. Bioconjugation methods were compared, including direct conjugation and post-insertion. The results showed that 9G8-attached PMSEA mRNA-LNPs prepared via direct conjugation significantly enhanced cell association and in vitro transfection efficiency with an EGFR-positive cell line, demonstrating the potency of active targeting for mRNA-LNP platforms with side-chain polymer coatings.
Choy et al. (Thu,) studied this question.