调控肿瘤微环境的智能型纳米药物增敏肝癌微波消融治疗的基础研究

The high rate of intrahepatic recurrence after microwave ablation(MWA) was attributed to the residual tumors or the de novo carcinogenesis, which was also the bottleneck restriction for the clinical effectiveness of MWA. Strengthening the precise control of thermal field and improving the microenvironment of tumors are the key to solve the difficulty. Our study designed an intelligent nanoparticle loaded with different drugs which could be released in controlled manner and in pointed location. First, the Galunisertib attached in the surface of liposome nanoparticles could be released in the acid microenvironment of hepatic tumors to inhibit of TGF-β signal, which orchestrate the whole microenvironment organization and the consequent tumor/stroma cross-talk. The released drug would help to reduce the inflammatory reaction and collagen production. Also, it could facilitate the residual core of nanoparticles move towards the tumor cells. Then, the microwave irradiation would be applied and ions encapsulated in the core of nanoparticles would collide fiercely, producing more heat in the limited space. Consequently, thermal-sensitive liposome would rupture and release the encapsulated doxorubicin(DOX) quickly. The addition of DOX will enhance the anti-tumor effect of MWA. Finally, the precise location and controlled release of drugs were achieved in pre-set time and space. The intelligent nanoparticle well combined the mediation of tumor environment with the improvement of MWA sensitivity, which could create new mini-invasive treatment modality based on nano-technology. The successful preparation of the intelligent nanoparticle is expected to provide new solutions to the difficulties in MWA.

肝癌微波消融后肿瘤细胞残存和再生是造成肝内肿瘤高复发转移的主要原因，也是目前制约微波消融疗效的瓶颈问题。加强微波热场有效布控并改善肝癌微环境是解决这一难题的关键。本课题拟构建一种智能型双靶向纳米药物，首先通过纳米壳外挂药物Galunisertib在肝癌微环境中特异性释放，抑制肝癌微环境中“大管家”TGF-β信号通路，达到减轻炎性免疫反应、降低纤维化的调控微环境效果，同时促进肿瘤细胞对剩余纳米内核的吸收；而后利用智能型纳米粒的微波响应特性，实现微波热场高效、精准布控及纳米核内次靶药物阿霉素在肿瘤内快速释放，协同微波消融加强对局部肿瘤细胞的杀伤效果。最终通过智能型纳米药物在不同空间、时间的精准定位和有序释放，实现纳米药物调控肿瘤微环境与增加微波消融敏感性的有机结合，以建立基于纳米技术的微创治疗新模式，为解决肝癌消融治疗的瓶颈问题提供新策略。

肝癌治疗后高复发转移率是制约肝癌疗效的瓶颈问题，而肝硬化肝癌特殊的炎性微环境是造成高复发转移的关键因素。本项目构建了一种智能型双靶向纳米药物，利用肝硬化微环境里面的基质金属蛋白酶（MMP），实现特异性剪切纳米药物表面的TGF-β阻滞剂Galunisertib药物，降解纤维化胶原蛋白，扫清药物吸收途径上的障碍，同时抑制炎性因子的表达，促进肿瘤组织对纳米内核的吸收，利用微波辐照促进内核药物PDE5抑制剂Tadalafil的快速释放，抑制肿瘤微环境中MDSC细胞的数目和功能，起到增敏微波消融疗效的目的。合成的纳米药物粒径约为132.2±0.4nm，Tadalafil及Galunisertib在智能型双靶向载药纳米颗粒的包封率分别为51.1%及37.3%，载药量分别为51.4%及39.3%；智能型双靶向载药纳米颗粒在体内环境下具有良好的稳定性，在加入MMP水解后，6h Tadalafil及Galunisertib的释放量为5.3%及32.4%；24h后Tadalafil及GAL的释放量为30.2%及56.3%，给予微波作用后，Tadalafil及Galunisertib的释放量高达为83.1%及90.2%，且合成的纳米药物可以在肝脏及肿瘤组织内有效富集。成功建立肝硬化-肝癌原位肿瘤模型，通过联系监测肝脏弹性及病理切片染色MASSON及SMA，均提示肝纤维化模型搭建成功，且纳米药物可以有效降解纤维化，通过检测脾脏及肿瘤组织的免疫因子表达，提示项目设计研发的智能型双靶向载药纳米颗粒可以解除肝癌微环境的免疫抑制状态，促进肝癌微波消融治疗效果。该项目为日后肝癌的综合治疗提供新思路，单纯针对肿瘤细胞的治疗完全不能扼杀肿瘤细胞，通过改善肿瘤懒以生存的微环境土壤，有望从根本上降低肝癌复发和转移率。