Norcantharidin liposome emulsion hybrid delivery system enhances PD-1/PD-L1 immunotherapy by agonizing the non-canonical NF-κB pathway.

PD-1/L1 checkpoint blockade has gained approval in terms of treating patients suffering from hepatocellular carcinoma (HCC). It should be noted that the PD-1/L1 inhibitor (α-PD-1/L1) has a low overall response rate when used as a single agent. Accordingly, the combination of α-PD-1/L1 and a series of therapies to further increase the response rate has become a major research direction. In our previous study, we developed a novel norcantharidin (NCTD) liposome emulsion hybrid delivery system (NE) with enhanced anticancer activity and reduced toxicity. In this study, NE was combined with α-PD-1/L1 for treating HCC. The combination therapy exhibited an enhanced antitumor activity, which led to the up-regulated expression levels of white blood cells, interleukin 12 (IL-12), interferon γ (IFN-γ), PD-L1, as well as CD8. Furthermore, the combination of NE and α-PD-1 achieved the optimal efficiency. NCTD-based chemotherapy is capable of synergizing with α-PD-1/L1 while enhancing checkpoint immunotherapy. It follows a mechanism that NCTD agonizes the non-canonical NF-κB pathway of dendritic cells for better activating CD8+T cells. Furthermore, NCTD may enhance antitumor immunity due to the leukogenic effect. In brief, new therapeutic regimens were provided for anti-HCC treatment by integrating NE to PD-1/L1 immunotherapy.