摘　要：程序性死亡受体1（PD-1）/程序性死亡配体1（PD-L1）信号通路主要参与免疫负调控作用，且在许多类型的肿瘤的恶性发展中具有关键作用。PD-L1的高表达可促进肝细胞癌（HCC）的侵袭，提高肿瘤复发的风险。另外，PD-L1常作为免疫检查点的阻断靶点，主要通过单抗将其中和，引发抗肿瘤免疫反应。因此，PD-L1是HCC免疫治疗中极具潜力的靶点之一。本文主要探究纳米级功能化氧化石墨烯（GO-PEI-PEG）携带PD-L1 siRNA对肝癌细胞的恶性生物学行为的影响。研究结果显示，将GO-PEI-PEG/PD-L1 siRNA转染至MHCC97H细胞后，细胞的增殖和迁移均被抑制，细胞周期阻滞在G1期，且细胞凋亡的数目增多。进一步研究发现，GO-PEI-PEG/PD-L1 siRNA对MHCC97H细胞的抑制作用是通过阻碍AKT信号通路激活实现的。这些试验结果表明，GO-PEI-PEG具备优秀的递送性能，携带PD-L1 siRNA可有效干扰PD-L1表达，进而抑制肝癌细胞的恶性生物学行为，这为治疗HCC提供了更安全、有效的递送新策略。
关键词：氧化石墨烯；PD-L1；siRNA递送；肝癌；AKT信号通路
中图分类号：R735.7                             文献标志码：A               DOI：10.3969/j.issn.1007-7146.2023.04.007

Abstract: The programmed cell death protein 1 (PD-1)/ programmed cell death 1 ligand 1 (PD-L1) signaling pathway is mainly involved in negative immune regulation and plays a crucial role in the malignant development of many types of tumors. High expression of PD-L1 promotes HCC invasion and increases the risk of tumor recurrence. In addition, PD-L1 is often used as an immune checkpoint blockade target, mainly neutralized by monoclonal antibodies to trigger an anti-tumor immune response. Therefore, PD-L1 is one of the potential targets in HCC immunotherapy. This study mainly uses nano-scale functionalized graphene oxide (GO-PEI-PEG) to carry PD-L1 siRNA to explore the malignant biological effects on liver cancer cells. The results showed that after transfection of GO-PEI-PEG/PD-L1 siRNA into MHCC97H cells, the proliferation and migration of cells were inhibited, the cell cycle was arrested in the G1 phase, and the number of apoptotic cells increased. It was further found that the inhibitory effect of GO-PEI-PEG/PD-L1 siRNA on MHCC97H cells was achieved by blocking the activation of the AKT signaling pathway. These experimental results show that GO-PEI-PEG has excellent delivery performance, carries PD-L1 siRNA to effectively interfere with PD-L1 expression, and then inhibits the malignant biological behavior of liver cancer cells, which provides a safer and more effective delivery strategy for the treatment of HCC.
Key words: graphene oxide; PD-L1; delivery of siRNA; liver cancer; AKT signaling pathway
（Acta Laser Biology Sinica, 2023, 32(4): 345-352）