穿膜肽修饰TSPO靶向纳米诊疗剂用于胶质瘤边界多模式显像和残留灶光热治疗的研究

There is neither an imaging which can accurately delineate gliomas margins, nor an effective treatment for gliomas residual lesion. A triple-modality strategy, combined MR imaging, Photoacoustic imaging and Ramam imaging, may be as a promising strategy for delineating gliomas margins. It has been shown that nanoparticles mediated by cell penetrating peptide Tat can cross the blood-brain-barrier; TSPO (mitochondrial translocator protein) is overexpressed on gliomas cell and tissues, CB86 is a ligand which can specifically target to TSPO. After the conjugation with appropriate fluorescent dyes, Tat targeted TSPO (Tat-CB86) was proved to be able to target specially to the mitochondria in the glioma cell lines. Based on good properties of photocoustic and enhanced Raman spectroscopy in gold nanoparticles and excellent photothermal effect in polypyrrole nanoparticlle shell, core-shell au@polypyrrole nanoparticles, conjugated the Raman moleculars, are modified by Tat-CB86 and Gd-DOTA. The novel multifunctional theranostics agent can cross the blood brain barrier (BBB) and cell membranes, targeting gliomas. It will not only be used to detect gliomas margins, including MR imaging is performed before operation to make a plan for therapy, photoacoustic imaging is performed during operating to delineate the margins of gliomas, Raman imaging is conducted intraoperatively to guide gliomas resection and to determined whether there is residual tumor in the resected areas, but also be used for photothermal therapy for residual lesion. We suggest it would significantly promote the development of gliomas targeted imaging and therapy in the future.

目前尚无准确定位胶质瘤边界的显像方法，也无术后残留灶有效治疗措施。研究表明MR、光声和拉曼光谱多模式显像有望准确定位胶质瘤边界,但其探针有待进一步优化；我们研究证实穿膜肽Tat能携带纳米颗粒跨过血脑屏障进入脑内；胶质瘤高表达线粒体转运蛋白（TSPO），配体CB86能与其高效结合；靶向性穿膜肽Tat-CB8仍具有胶质瘤高靶向性。本项目利用金纳米优良的光声和增强拉曼光谱特性及聚吡咯纳米壳显著的光热效应，用Tat-CB86和MR造影剂Gd-DOTA偶联吸附拉曼分子核-壳结构金@聚吡咯纳米颗粒，获得能通过血脑屏障胶质瘤靶向的纳米诊疗剂，实现同一制剂通过其高靶向性用于胶质瘤边界多模式显像（术前MR显像制定手术方案，术中光声显像定位肿瘤边界，指导手术，术后切缘拉曼光谱判断肿瘤是否残留），同时对未能全切除的残留灶行光热治疗，以达到提高胶质瘤治疗效果的目的。此研究对胶质瘤诊断与治疗将产生深远的促进作用。

胶质瘤呈浸润性生长，与周边正常脑组织的界限不清，微小病灶肉眼难于鉴别，手术难以全切除。开发胶质瘤特异性强、靶向性高的多功能制剂用胶质微小病定位显像和残留灶靶向治疗显得非常重要。此外，类风湿性关节炎早期诊断和早期治疗对降低类风湿性关节炎致残率极其重要，针对早期炎症过程的特定示踪剂将能早期地检测出类风湿性关节炎。本项目按研究计划执行，本项目证实了：① 本项目组自主合成的靶向TSPO（转运蛋白，18 kDa）新型配体VUIIS1008（也命名SXH 1001）和CB86具有高特异性靶向胶质瘤细胞、活化小胶质细胞和活化巨噬细胞TSPO受体；② 在胶质瘤和类风湿性关节炎中胶质瘤细胞或活化巨噬细胞中的位于线粒体外膜上的TSPO呈现高表达，用放射性显像核素18F、99mTc或磁共振显像用的金属元素钆或荧光染料标记新型配体VUIIS1008或CB86，即可制备PET显像分子探针、SPECT显像分子探针、MRI分子探针或荧光显像分子探针，行PET、SPECT、MRI术前诊断胶质瘤和类风湿性关节炎，在术中荧光显像显示微小胶质瘤病灶（<1.0cm）指导外科医生彻底切除肿瘤。此外，对不能手术肿瘤病灶行在近红线照射下，靶向性分子探针SiO2@dRB-CB86能产热，肿瘤组织温度上升，导致肿瘤细胞死亡，杀死癌细胞，提高肿瘤治愈率。共发表论文18篇，其中SCI收录期刊发表论文15篇，中文核心期刊发表3篇；申请专利10项，其中获授权专利5项，发明专利2项，实用型专利3项；科研获奖5项，其中福建省科技进步奖二、三等奖各1项，福建省医学科技奖二、三等奖各1项，厦门市科技进步奖二等奖1项；培养已毕业研究生7名。