Engineering Immunotherapeutic Exosomes from Dendritic Cells Stimulated by Intracellular Self-Assembled Peptide Networks for Cancer Vaccine

Here we inrtoduce a new approach for generating immunotherapeutic nanoparticles of dendritic cell (DC)-derived exosomes (DC-Exos) on a large-scale for the clinical translation. Exosomes denote a family of nanoparticles (30–120 nm in a diameter) secreted by most cell types. Secreted exosomes consist of a surrounding lipid bilayer containing various proteins, lipids, and nucleic acids in donor cells. The use of DC-derived exosomes was recognized to address the technical challenges associated with DC-based immunotherapy, leading to multiple clinical trials. However, the workload required to upscale the production of DC-Exos is currently not suitable for their major clinical use. Our lab has been showing that a peptide (NapFFK(NBD)Yp) self-assembles in fiber networks in the cytoplasm of donor cells, catalyzed by alkaline phosphatases (ALPs), and such peptide self-assembly can increase the secretion of exosomes in various cancer cells, reaching in some cases a 10-fold increase. We observed that the peptide self-assembly was triggered by ALP in DCs, in which the expression of required enzyme was induced by specific growth factors, and this assembly stimulated mass production of DC-Exos; the production of exosomes from bone marrow-derived DCs was amplified 7-folds by the self-assembled peptide without inducing major toxicity. We also showed the potential that the self-assembled peptide could activate DCs to become strong stimulators of the immune response by triggering pro-inflammatory recognition mechanisms <i>via</i> proteomic analysis and flow cytometry. With proteomics, the heatmap of protein expression of exosomes with the peptide treatment indicates the packaging of exosomes is not affected by self-assembled peptides in parental cells, an important condition for their clinical applications. The proteomics could also suggest possible biogenesis and mechanism of amplified generation of exosomes.<br/>The outcome could advance scientific knowledge for precision medicine as proposed exosomes can be applied as intercellular vectors for personal RNA-based therapy (both miRNAs and siRNAs) with capability of individualized-specific targeting of cancers and suppression of immunogenic response. It will also lay the foundations for future studies implementing DC-Exos as delivery systems in mRNA vaccine, cardiovascular diseases-related RNA therapeutics that can be regulated through exosomes.