MR引导聚焦超声开放BBTB协同增强VEGF/SLUG双靶点基因治疗多形性胶质母细胞瘤的实验研究

Blood brain tumor barrier (BBTB) is one of the major hurdle to the treatment of the glioblastoma multiforme (GBM). Focused ultrasound (FUS) at different frequencies can be used to open the BBTB and to ablate the GBM tumor. However, the tumor cells of the peripheral part hard to achieve the effective killing temperature when ablated by FUS, due to the abundant blood flow. The non-killed cancer cells will stimulate the recurrence and the resistance to treatment of the tumor, through the initiation of angiogenesis and epithelial-mesenchymal transition (EMT). Aimed at the above clinical problems, and based on the previous work, in this project, the VEGF and the SLUG will be used as the targets of gene regulation, the VEGFsiRNA-PEG-SPIO and the SLUGsiRNA-PEG-SPIO will be synthesized as the theranostic nanoprobes. The BBTB will be disrupted by the low frequency FUS, to help more theranostic nanoprobes crossing the BBTB to delivering into the peripheral part of the GBM tumor. These theranostic nanoprobes will inhibit the angiogenesis and the EMT of tumor, by knockdown the expression of VEGF and SLUG. This gene therapy will be combined with the FUS ablation for the GBM treatment. The magnetic resonance imaging (MRI) will be used for the visual monitoring of the nanoprobes transferring in vivo and the assessment of the treatment efficacy. The findings will clarify the principle of FUS opening the BBTB, and the mechanism of the synergistic effect of the FUS ablation combined with gene therapy. This project will open a new avenue for the treatment of GBM.

血脑肿瘤屏障（BBTB）的存在严重影响多形性胶质母细胞瘤（GBM）的综合治疗效果。不同频率的聚焦超声（FUS）可用于开放BBTB和GBM的消融治疗。但FUS消融治疗时，肿瘤周边部分由于血流丰富而无法达到有效升温，未被“杀死”的癌细胞通过启动血管生成和内皮-间质转化（EMT）刺激残瘤生长和治疗抵抗。本项目在前期工作基础上，以VEGF和SLUG为基因调控双靶点，构建诊治一体化纳米探针VEGFsiRNA-PEG-SPIO和SLUGsiRNA-PEG-SPIO；在磁共振引导下运用低频FUS打开荷瘤鼠BBTB，促进纳米探针进入血供丰富的肿瘤周边部位；下调VEGF和SLUG的表达，抑制肿瘤血管生成和EMT；协同增强FUS消融GBM的治疗效果；并运用磁共振活体可视化监测纳米探针的转运和评估疗效。从而阐明FUS开放BBTB的原理，以及FUS消融与基因治疗之间的协同增强效应与机制，为GBM的治疗探索新方法。

多形性胶质母细胞瘤（glioblastoma multiforme, GBM）是最常见的原发性恶性脑肿瘤，血脑肿瘤屏障（BBTB）的存在严重影响多形性胶质母细胞瘤（GBM）的综合治疗效果。磁共振引导聚焦超声（FUS）的应用，联合多功能纳⽶材料，可以实现在MRI的监测下⽰踪超声打开BBTB及药物进⼊脑肿瘤组织的全过程，提高肿瘤的治疗效果，为GBM 治疗探索有效的新方法。本项目的成果包括：1）研发构建多功能PVCL纳米凝胶，在MRI引导下实现原位胶质母细胞瘤的T1加权成像，运用磁共振活体可视化监测纳米探针的转运和评估疗效，实现体内免疫激活，联合放疗，增强GBM的抗肿瘤效果；2）开发肿瘤微环境激活ROS生成的基于蛋白的多级自组装纳米药物，载有级联酶和光敏剂，实现对肿瘤的化学动力学治疗和光动力学联合治疗；3）研发出了具备自主知识产权的MRIpHIFU肿瘤治疗系统及小动物平台，阐明FUS开放BBTB的原理，并对BBTB开放的参数进行优化；4）构建了基于树状大分子包裹金纳米颗粒的工程化巨噬细胞，Au DENPs可以激活巨噬细胞成为M1型巨噬细胞，激活TLR-4信号通路，促进肿瘤细胞的凋亡，同时联合应用化疗药物DOX，可有效增强工程化巨噬细胞的抗肿瘤作用。综上所述，本项目研发制备了多种新型纳米凝胶及肿瘤微环境响应的多级自组装纳米复合物，在磁共振可视化监测下优化了靶向药物释控，并联合应用目前新兴的免疫治疗、化学动力学治疗、光动力学治疗以及传统的放化疗相结合的方式，进行联合治疗，显著提高脑肿瘤的治疗效果，同时降低治疗过程中可能对病人产生的副作用，阐明了多种联合治疗之间的协同增强效应与机制，为GBM 治疗及潜在的临床转化奠定了理论依据。本项目研究成果在Chemical Engineering Journal、Small等期刊发表论文11篇，其中SCI论著9篇，中华医学系列期刊综述1篇，核心期刊论文1篇。