Scheme 1.

Schematic illustration of TB/PTX@RTK micelles mediated chemo-PDT to potentiate immune checkpoint blockade therapy. TB/PTX@RTK micelles enter tumor cells through active targeting. Under light irradiation, photosensitizer TB in micelles uses oxygen to generate ROS and PTX is immediately released from the micelles, causing ICD and releasing TAA for dendritic cells (DCs) maturation, migration, and cytotoxic T cell activation. Meanwhile, TB/PTX@RTK mediated chemo-PDT could significantly upregulate the expression of PD-L1 on tumor cells and reverse the immunosuppressive tumor microenvironment. Combination chemo-PDT with anti-PD-L1 antibody induces complete tumor regression of primary tumors and efficiently inhibits distant metastatic tumors by triggering anti-tumor immune responses. Finally, immunological memory established by chemo-PDT with PD-L1 blockade efficiently prevents tumor recurrence by rechallenged tumor cells