FcBP-HFQ lipid-mediated trastuzumab modification of mRNA-loaded lipid nanoparticles enhances delivery to HER2-expressing cancer cells.

Lipid nanoparticles (LNPs) have emerged as a key delivery platform for mRNA therapeutics, as demonstrated by the clinical success of mRNA vaccines against SARS-CoV-2. LNPs are now being investigated for various applications, such as cancer immunotherapy and the treatment of genetic disorders. However, LNPs tend to accumulate predominantly in the liver and lack intrinsic cell-type specificity. Modifying LNPs with antibodies is a promising strategy for enhancing cell-specific delivery. We have previously developed orientation-controlled anti-transferrin receptor and anti-PD-L1 antibody modifications for the targeted delivery of nucleic acids, including mRNA and siRNA. In this study, we newly applied this platform to trastuzumab, a clinically established high-affinity anti-HER2 therapeutic antibody, to develop orientation-controlled trastuzumab-modified mRNA/LNPs for HER2-selective delivery. we evaluated trastuzumab-modified mRNA/LNPs in HER2-overexpressing SKOV-3 ovarian cancer cells and HER2-low MDA-MB-231 breast cancer cells. Trastuzumab-modified mRNA/LNPs exhibited over 100-fold greater cellular association than unmodified LNPs in cultured HER2-overexpressing SKOV-3 cells. Furthermore, after intratumoral administration in a mouse model bearing subcutaneous SKOV-3 tumors, the trastuzumab-modified group showed significantly higher luciferase expression than the unmodified and isotype-controlled antibody-modified groups. These findings support FcBP-HFQ lipid-mediated trastuzumab modification of LNPs as a useful approach for efficient cell-selective mRNA delivery.