酸敏诊疗一体化MnAs纳米药物对抗肝癌TACE术后残癌的实验研究

The residual tumor and tumor recurrence after transcatheter arterial chemoembolization (TACE) lead to poor long-term efficacy. Therefore, to enhance therapeutic efficacy, it's crucial to efficiently diagnose and treat the residual cancer after TACE. Tumor acidic microenvironment can be used as a target for cancer treatment. Additionally, ischemia and hypoxia after vascular embolism further promote the formation of cancer acid microenvironment. Combining Mn2+ that shorten the T1 relaxation time of magnetic resonance (MR) with the anti-HCC effect of As3+, we design and constructed an acidic cell-penetrating peptide labeled acid sensitive integrative MnAs nanodrug. Preliminary experiments show that the nanodrug has obvious human hepatocellular carcinoma inhibitory effect and MRI signal enhancement both in vitro and on mice subcutaneous xenograft models. In order to further understand the role of this nanodrug in the diagnosis and treatment of residual cancer after TACE, this project intends to operate TACE in rat model of liver cancer in situ. Taking advantage of precise administration via hepatic artery, we aim to promote the enrichment of the MnAs nanodrug in the residual tumor tissue and to monitor it with MR in vivo. The success of this project will not only provides a new system for efficient and accurate diagnosis, but also may lead to ultimate treatment of residual cancer after TACE in hepatocellular carcinoma, which is expected to further improve the long-term efficacy.

经肝动脉化疗栓塞（TACE）术后肿瘤残余及残癌复发导致肝癌远期疗效不佳。因此，对残癌进行高效诊断并精准治疗是提高疗效的关键。肿瘤微酸性环境可做为肿瘤治疗的靶点，而血管栓塞后缺血缺氧进一步促进了残癌酸性微环境的形成。利用二价锰离子（Mn2+）缩短磁共振（MR）T1弛豫时间及三价砷离子（As3+）的抗肝癌作用，我们设计并构建了酸性细胞穿膜肽标记的酸敏诊疗一体化MnAs纳米药物。预实验显示该纳米药物在体外及小鼠皮下人肝癌移植瘤模型中均具有明显肿瘤抑制作用及MR增强效果。为进一步研究该纳米药物在TACE术后残癌诊疗中的作用，本课题拟采用大鼠原位肝癌模型行TACE治疗，利用经肝动脉精准给药的优势，将酸敏诊疗一体化MnAs纳米药物定向输送至肿瘤组织，旨在促进药物在残癌组织的富集，并以MR活体下进行残癌监测。本项目将提供肝癌TACE术后残癌高效诊断评估、精准治疗的新系统，有望进一步提高肝癌远期疗效。

肝细胞癌(HCC)的治疗因疗效差及易复发而受阻，主要原因有化疗药物肝癌的靶向性差、肿瘤中存在大量肿瘤干细胞以及肿瘤细胞发生上皮间质转化（EMT）而导致耐药等。针对药物靶向性的问题，我们开发了一种酸敏肽修饰的多功能药物递送系统MnAs@SiO2-pHLIP，其能够有效靶向肿瘤微酸环境，导致肝癌组织内药物富集，并能够在酸性环境下可控地释放负载的三氧化二砷（ATO），从而高效的诱导肝癌细胞凋亡。与游离ATO相比，可控释放能力和出色的靶向性使其具有更好的抗癌效果、降低对正常组织的毒性。酸性的肿瘤微环境还会触发锰离子(Mn2+)的释放，使T1信号增强，利用其进行对比增强磁共振成像(MRI)实时监测。针对肿瘤干细胞以及EMT等影响肝癌疗效的难题，我们开发了基于三氧化二砷的新型纳米颗粒ZnAs@SiO2，其能高效的促进肝癌细胞凋亡并能显著抑制肝癌细胞的增殖、迁移和侵袭；还能在体外抑制肿瘤球状形成、体内抑制肿瘤发生，并在体内和体外诱导干性标志物和EMT标志物的表达发生显著变化；体内实验中，ZnAs@SiO2 纳米药物能高效抑制肿瘤生长及转移。同时我们证实ZnAs@SiO2与HCC预后相关的作用是通过SHP-1/JAK2/STAT3信号通路介导的。在研究肝癌细胞EMT的机制过程中，我们在HCC细胞中发现了一个由circPTK2/miR-92a/E-cadherin组成的调控轴，肝癌中高表达的miR-92a可通过靶向E-cadherin 3’UTR促进肝癌细胞增殖和侵袭，circPTK2通过抑制miR-92a抑制EMT。本项目针对肝癌治疗疗效差的相关因素进行了机制及解决方案的探索，成功的设计并制备了能高效抑制肝癌的载药体系MnAs@SiO2-pHLIP及ZnAs@SiO2，同时我们发现并验证circPTK2/miR-92a/E-cadherin调控肝癌EMT的通路。以上研究成果为肝癌治疗提供能新策略及新靶点。