Dual pH-sensitive nanodrug blocks PD-1 immune checkpoint and uses T cells to deliver NF-κB inhibitor for antitumor immunotherapy

The response to programmed cell death protein-1 (PD-1)/programmed death ligand-1 (PD-L1) blockade in cancer immunotherapy is limited because of multiple immune evasion mechanisms. Here, a previously unknown strategy is proposed to synergize the nuclear factor κB (NF-κB) inhibition and PD-1 blockade for antitumor immunotherapy. A dual pH-sensitive nanocarrier loading curcumin (CUR) and anti-PD-1 monoclonal antibody (aPD-1) may bind to circulating PD-1 T cells and then follow their infiltration into the tumor. Furthermore, the nanodrug bound to PD-1 T cells may be released in the tumor microenvironment, leaving aPD-1 to block PD-1 on T cells and generating a CUR-encapsulated cationic nanodrug that can be easily taken up by tumor cells/tumor associated macrophages (TAMs). Thus, not only the antitumor T cells mediate efficient CUR delivery to tumor but also the efficient CUR delivery promotes the tumor infiltration of antitumor T cells, thereby resulting in effective activation of antitumor immunity.