Photosensitization Priming of Tumor Microenvironments Improves Delivery of Nanotherapeutics via Neutrophil Infiltration.

Remodeling of tumor microenvironments enables enhanced delivery of nanoparticles (NPs). This study shows that direct priming of a tumor tissue using photosensitization rapidly activates neutrophil infiltration that mediates delivery of nanotherapeutics into the tumor. A drug delivery platform is comprised of NPs coated with anti-CD11b antibodies (Abs) that target activated neutrophils. Intravital microscopy demonstrates that the movement of anti-CD11b Abs-decorated NPs (NPs-CD11b) into the tumor is mediated by neutrophil infiltration induced by photosensitization (PS) because the systemic depletion of neutrophils completely abolishes the nanoparticle tumor deposition. The neutrophil uptake of NPs does not alter neutrophil activation and transmigration. For cancer therapy in mice, tumor PS and photothermal therapy of anti-CD11b Abs-linked gold nanorods (GNRs-CD11b) are combined to treat the carcinoma tumor. The result indicates that neutrophil tumor infiltration enhances nanoparticle cancer therapy. The findings reveal that promoting tumor infiltration of neutrophils by manipulating tumor microenvironments could be a novel strategy to actively deliver nanotherapeutics in cancer therapies.