FAP-Targeted Photodynamic Therapy Mediated by Ferritin Nanoparticles Elicits an Immune Response against Cancer Cells and Cancer Associated Fibroblasts

ABSTRACT: Cancer-associated fibroblasts (CAFs) are present in many types of tumors and play a pivotal role in tumor progression and immunosuppression. Fibroblast-activation protein (FAP), which is overexpressed on CAFs, has been indicated as a universal tumor target. However, FAP expression is not restricted to tumors, and systemic treatment against FAP often causes severe side effects. To solve this problem, a photodynamic therapy (PDT) approach was developed based on ZnF16Pc (a photosensitizer)-loaded and FAP-specific single chain variable fragment (scFv)-conjugated apoferritin nanoparticles, or αFAP-Z@FRT. αFAP-Z@FRT PDT efficiently eradicates CAFs in tumors without inducing systemic toxicity. When tested in murine 4T1 models, the PDT treatment elicits anti-cancer immunity, causing suppression of both primary and distant tumors, i.e. abscopal effect. Treatment efficacy is enhanced when αFAP-Z@FRT PDT is used in combination with anti-PD1 antibodies. Interestingly, it is found that the PDT treatment not only elicits a cellular immunity against cancer cells, but also stimulates an anti-CAFs immunity. This is supported by an adoptive cell transfer study, where T cells taken from 4T1-tumor-bearing animals treated with αFAP PDT retard the growth of A549 tumors established on nude mice. Overall, our approach is unique for permitting site-specific eradication of CAFs and inducing a broad spectrum anti-cancer immunity. Graphical Abstract Anti-FAP photodynamic therapy, mediated by ZnF16Pc-loaded and single-chain variable-fragment (scFv)-conjugated ferritin nanoparticles, eliminates cancer associated fibroblasts (CAFs) in a specific fashion. This results in destructed extracellular matrix and reduced recruitment of regulatory T cells. In turn, the treatment enhances the expansion of anti-cancer and anti-CAF cytotoxic T lymphocytes, eliciting an immunity that inhibits tumor growth.

SUBMITTER: Zhou S 

PROVIDER: S-EPMC9273013 | biostudies-literature |

REPOSITORIES: biostudies-literature