Engineered CpG-Loaded Nanorobots Drive Autophagy-Mediated Immunity for TLR9-Positive Cancer Therapy.

Smart nanorobots have emerged as novel drug delivery platforms in nanomedicine, potentially improving anti-cancer efficacy and reducing side effects. In this study, we developed an intelligent tumor microenvironment-responsive nanorobot that effectively delivers CpG payloads to Toll-like receptor 9 (TLR9)-positive tumors to induce autophagy-mediated cell death for immunotherapy. The nanorobots were fabricated by co-self-assembly of two amphiphilic triblock polymer peptides: one containing the MMP2-cleaved GPLGVRGS motif to control the mechanical opening of the nanorobots and provide targeting capability for TLR-9-positive tumors and the other consisting of an arginine-rich GRRRDRGRS sequence that can condense nuclear acid payloads through electrostatic interactions. Using multiple tumor-bearing mouse models, we investigated whether the intravenous injection of CpG-loaded nanorobots could effectively deliver CpG payloads to TLR-9-positive tumors and elicit anti-tumor immunity through TLR9 signaling and autophagy. Therefore, besides being a commonly used adjuvant for tumor vaccination, CpG-loaded nanorobots can effectively reprogram the tumor immunosuppressive microenvironment and suppress tumor growth and recurrence. This nanorobot-based CpG immunotherapy can be considered a feasible approach to induce anti-tumor immunity, showing great therapeutic potential for the future treatment of TLR9-positive cancers. This article is protected by copyright. All rights reserved.