CpG-coated Prussian blue nanoparticles-based photothermal therapy combined with anti-CTLA-4 immune checkpoint blockade triggers a robust abscopal effect against neuroblastoma
Abscopal effect; CpG oligodeoxynucleotides; Immune checkpoint blockade; Nanoimmunotherapy; Neuroblastoma; Prussian blue nanoparticles-based photothermal therapy
© 2020 The Authors High-risk neuroblastoma, which is associated with regional and systemic metastasis, is a leading cause of cancer-related mortality in children. Responding to this need for novel therapies for high-risk patients, we have developed a “nanoimmunotherapy,” which combines photothermal therapy (PTT) using CpG oligodeoxynucleotide-coated Prussian blue nanoparticles (CpG-PBNPs) combined with anti-CTLA-4 (aCTLA-4) immunotherapy. Our in vitro studies demonstrate that in addition to causing ablative tumor cell death, our nanoimmunotherapy alters the surface levels of co-stimulatory, antigen-presenting, and co-inhibitory molecules on neuroblastoma tumor cells. When administered in a syngeneic, murine model of neuroblastoma bearing synchronous Neuro2a tumors, the CpG-PBNP-PTT plus aCTLA-4 nanoimmunotherapy elicits complete tumor regression in both primary (CpG-PBNP-PTT-treated) and secondary tumors, and long-term survival in a significantly higher proportion (55.5%) of treated-mice compared with the controls. Furthermore, the surviving, nanoimmunotherapy-treated animals reject Neuro2a rechallenge, suggesting that the therapy generates immunological memory. Additionally, the depletion of CD4+, CD8+, and NK+ populations abrogate the observed therapeutic responses of the nanoimmunotherapy. These findings demonstrate the importance of concurrent PTT-based cytotoxicity and the antitumor immune effects of PTT, CpG, and aCTLA-4 in generating a robust abscopal effect against neuroblastoma.
Cano-Mejia, J., Shukla, A., Ledezma, D., Palmer, E., Villagra, A., & Fernandes, R. (2020). CpG-coated Prussian blue nanoparticles-based photothermal therapy combined with anti-CTLA-4 immune checkpoint blockade triggers a robust abscopal effect against neuroblastoma. Translational Oncology, 13 (10). http://dx.doi.org/10.1016/j.tranon.2020.100823