High-precision targeting and destruction of cancer-associated PDGFR-β plus stromal fibroblasts through self-assembling, protein-only nanoparticles

The need for more effective and precision medicines for cancer has pushed the exploration of new mate-rials appropriate for drug delivery and imaging, and alternative receptors for targeting. Among the most promising strategies, finding suitable cell surface receptors and targeting agents for cancer-associated platelet derived growth factor receptor fi (PDGFR-fi)+ stromal fibroblasts is highly appealing. As a ne-glected target, this cell type mechanically and biologically supports the growth, progression, and infiltra-tion of solid tumors in non-small cell lung, breast, pancreatic, and colorectal cancers. We have developed a family of PDGFR-fi-targeted nanoparticles based on biofabricated, self-assembling proteins, upon hierar-chical and iterative selective processes starting from four initial candidates. The modular protein PDGFD-GFP-H6 is well produced in recombinant bacteria, resulting in structurally robust oligomeric particles that selectively penetrates into PDGFR-fi+ stromal fibroblasts in a dose-dependent manner, by means of the PDGFR-fi ligand PDGFD. Upon in vivo administration, these GFP-carrying protein nanoparticles precisely accumulate in tumor tissues and enlighten them for IVIS observation. When GFP is replaced by a micro-bial toxin, selective tumor tissue destruction is observed associated with a significant reduction in tumor volume growth. The presented data validate the PDGFR-fi/PDGFD pair as a promising toolbox for tar-geted drug delivery in the tumor microenvironment and oligomeric protein nanoparticles as a powerful instrument to mediate highly selective biosafe targeting in cancer through non-cancer cells. Statement of significance We have developed a transversal platform for nanoparticle-based drug delivery into cancer-associated fibroblasts. This is based on the engineered modular protein PDGFD-GFP-H6 that spontaneously self-assemble and selectively penetrates into PDGFR-fi+ stromal fibroblasts in a dose-dependent manner, by means of the PDGFR-fi ligand PDGFD. In vivo, these protein nanoparticles accumulate in tumor and when incorporating a microbial toxin, they destroy tumor tissues with a significant reduction in tumor volume, in absence of side toxicities. The data presented here validate the PDGFR-fi/PDGFD pair as a fully versatile toolbox for targeted drug delivery in the tumor microenvironment intended as a synergistic treatment. (c) 2023 The Author(s). Published by Elsevier Ltd on behalf of Acta Materialia Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

Automated summary

Researchers have developed biofabricated protein nanoparticles for targeted drug delivery into cancer-associated fibroblasts. These nanoparticles can selectively penetrate PDGFR-fi+ stromal fibroblasts and accumulate in tumor tissues, leading to tumor destruction without side effects.