双模态Her2靶向载DOX金纳米微囊介导光化疗协同增敏治疗乳腺癌的实验研究

The combination of chemotherapy and photothermal therapy is one comprehensive treatment for breast cancer with wide application prospect. However, precise synergistic effects of photothermo-chemotherpy therapy is difficult to realize because traditional treatment techniques cannot targeted breast cancer tissue at the molecular level, and the existing imaging tools cannot timely monitor the progress of treatments. How to achieve complete and effective visible therapy of breast cancer，and to monitor the treatment procedure in real-time, and to assess the effectiveness after therapy is an urgently problem that need to be resolved. The multifunctional nanocapsules that our subjects plans to design through the formation of Au Nanoshells around poly (lactic-co-glycolicacid) (PLGA) nanoparticles entrapping doxorubicin（DOX）has four patterns of functions which included ultrasound imaging, MR imaging and photothermal ablation and chemotherapy. The nanocapsules entrapping perfluorooctylbromide (PFOB), and followed by linking Mn-porphyrin derivative on the Au shell surface through polyethylene glycol, and then grafted with anti-Her2. With this multifunctional nanocapsules, we can improve the discrimination of malignant breast tumors, and achieve bimodal ultrasound/magnetic resonance imaging. The nanocapsules exhibited an efficient photohyperthermia and a light triggered and stepwise release behavior of doxorubicin，which can improve treatment effect and reduce drug toxicity and tumor drug resistance. The bimodal ultrasound/magnetic resonance imaging can correctly identify the tumor size and location before treatment, and can monitor the procedure in real-time during therapy, and assess the effectiveness after therapy，which can make up for the deficiency of single model. The multifunctional theranostic agent will prove a new way for the integration of molecule targeted adjuvant therapy and therapeutic effect evaluation of breast cancer.

光化疗联合应用是颇具前景的乳腺癌综合治疗模式。但传统的光化疗联合技术多为非靶向性，无法从分子水平识别癌组织，且现有的成像手段又无法及时监测疗效，因此很难实现精准的特异性治疗。如何实现可视化完整有效的乳腺癌治疗，同时又能对治疗过程和结果进行实时监测和评估是临床上亟需解决的问题。本课题拟制备集US/MRI/光热治疗/化疗为一体的载阿霉素（DOX）PLGA金纳米微囊，内包覆全氟溴辛烷外连接锰卟啉可实现US/MRI双模态成像，并以Her2作为乳腺癌定位识别的分子靶点；光热治疗的同时持续靶向调控药物释放和浓集，实现光化疗协同增敏治疗，以提高治疗效果，降低药物的毒副作用和肿瘤耐药性的产生；US/MRI双模态成像即可在治疗前对肿瘤的位置和大小进行准确的判断，又能对治疗过程及效果进行实时的检测和评估，弥补了单一成像的不足。该多功能纳米诊疗剂为实现乳腺癌靶向辅助诊疗及疗效评估的一体化提供了新思路。

光化疗联合应用是颇具前景的乳腺癌综合治疗模式。集光化疗和多模态成像为一体的多功能靶向纳米平台在实现乳腺癌精准特异性治疗方面具有重要价值。本研究中，我们成功构建了集US/MRI/光热治疗/化疗为一体的载阿霉素（DOX）金纳米壳聚乳酸羟基乙酸（PLGA）微囊，内包覆全氟辛基溴化物（PFOB），超顺磁性氧化铁纳米粒子（SPIOs），外面连接人类表皮生长因子受体2（Her2-PFOB/SPIOs/DOX@PLGA@Au NCs）, 简写为Her2-GPDH NCs。该纳米微囊具有良好的球形形态，平均直径约为296±32 nm，且具有良好的分散性。靶向研究分析表明Her2-GPDH NCs可特异性的靶向Her2阳性的乳腺癌SKBR3细胞。Her2-PFOB/SPIOs/DOX@PLGA@Au NCs中DOX的包封效率和负载量分别为39±1.45％和3.8±0.52％，且具有pH响应和近红外光触发的DOX逐步释放特性。在体外，该纳米微囊具有良好的超声和T2 MR成像效果。细胞实验证实光化疗联合应用可以明显增强对乳腺癌SKBR3细胞治疗效果。体内研究显示，该纳米微囊具有良好的生物相容性和较低的毒副作用。在BT474人乳腺癌裸鼠肿瘤模型中，该纳米微囊静脉注射具有良好的体内MR及光声成像效果，瘤内注射获得良好的超声成像效果。体内光化疗协同增敏治疗实验显示靶向光化疗联合治疗组具有最显著的治疗效果。该多功能纳米诊疗剂有望为实现乳腺癌靶向辅助治疗及疗效评估一体化提供了新思路。