Glycan targeting nanoparticle for photodynamic immunotherapy of melanoma

Interaction between tumour cells and macrophages enables cancer cells to evade immune detection and clearance by interfering with macrophage phagocytosis. The anti-phagocytic signals regu-lated by anti-phagocytic proteins are termed don't eat me signals; these signals include sialic acid -binding immunoglobulin-type lectin-10 (Siglec-10) and the recently revealed CD24 immune checkpoint (ICP). In this study, we demonstrate that targeting a specific glycan on CD24 exhibits the potential to inhibit ICP. Sambucus nigra agglutinin (SNA), a sialic acid-binding lectin, was employed to block CD24 and to enhance phagocytosis in melanoma tumours. In addition, we prepared SNA-conjugated hol-low gold-iron oxide nanoparticles for photothermal therapy of tumours. Our findings show that the com-bination treatment of SNA-conjugated photothermal nanoparticles and near-infrared exposure successfully augments tumour cell phagocytosis both in vitro and in vivo models.(c) 2023 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The interaction between tumour cells and macrophages allows cancer cells to escape immune detection and clearance by interfering with macrophage phagocytosis. This study demonstrates the potential of targeting a specific glycan on CD24 to inhibit immune checkpoint. Sambucus nigra agglutinin (SNA), a sialic acid-binding lectin, was used to block CD24 and enhance phagocytosis in melanoma tumours. Additionally, SNA-conjugated hollow gold-iron oxide nanoparticles were prepared for photothermal therapy of tumours, and the combination treatment successfully increased tumour cell phagocytosis in vitro and in vivo models.