Leucocyte-hitchhiking liposomes loading gemcitabine and pyroptosis for potentiated immunotherapy of hepatocellular carcinoma.

168 Background: Hepatocellular carcinoma (HCC), as a malignant tumor with high incidence worldwide, faces the challenge of low efficacy of traditional chemotherapy drugs and immunotherapy drugs. Pyroptosis is a type of programmed cell death that can alleviate tumor immunosuppressive microenvironment and promote systemic immune response, which has great potential in improving the efficacy of immunotherapy drugs. The selection of more effective pyroptosis-inducing drugs and immunotherapy drugs, supplemented by more precise drug delivery strategies, is one of the research focuses in the treatment of HCC. Methods: In this study, Western Blot were performed to screen suitable pyroptosis-inducing drugs. A leucocyte-hitchhiking liposome nanodrug delivery system was designed to co-deliver a pyroptosis-inducing drug and a small molecule immunotherapy drug. The ability of the nanocarrier to induce pyroptosis of liver cancer cells and to activate immune cells were investigated in vitro. The targeting ability of the nanocarrier to peripheral blood leucocytes, the function of tumor inhibition and immune activation were evaluated in vivo. Results: In this study, gemcitabine was confirmed to induce pyroptosis in liver cancer cells. E-selectin modified liposomes were designed to co-deliver gemcitabine and the small molecule PD-1/PD-L1 complex inhibitor BMS-202. In vitro experiments confirmed that the nanocarrier could induce pyroptosis in liver cancer cells and activate immune cells. In vitro experiments confirmed the targeting ability of the nanocarrier to leukocytes and its ability to inhibit tumor and activate immunity. Conclusions: Leucocyte-hitchhiking liposomes loading gemcitabine and BMS-202 was successfully synthesized. After intravenous injection, liposomes effectively adhere to the surface of peripheral blood leukocytes mediated by E-selectin, thus hitchhiking with leukocytes to achieve high accumulation at the tumor site. The released gemcitabine can evoke tumor cell pyroptosis and generate anti-tumor immunity, while BMS-202 can alleviate immune suppression by inhibiting the formation of PD-1/PD-L1 complex, further enhance gemcitabine-induced anti-tumor immunity. This leucocyte-hitchhiking dual-delivery liposomal nanoplatform might provide a promising strategy for high-efficiency immunotherapy, exhibiting a great potential for clinical translation of HCC treatment.