GCN5靶向纳米探针在胶质瘤恶性演进中的可视化意义与边界判定

The mechanism of glioma evolution is complex, malignant and invasive. Conventional imaging methods are difficult to detect peritumoralinvasive growth of glioma cells. Therefore, accurate determination of glioma margin and invasive extent is of great significance to guide the surgical resection margin. Gene mutation at somatic level is an important feature of tumors. We used large data analysis to annotate the mutation, screened out GCN5 and verified its driving function in malignant progression of glioma. Pathologically, we found that GCN5 was clearly expressed in glioma cells and related tomalignancegrading, but not in normal glioma cells. GCN5 could be used as a criterion to determine the boundary and infiltration of glioma. Therefore, this project intends to use DC-G16-11, a small molecule inhibitor of GCN5, binding with dendritichigh polymer（Dendrimer, Den）to synthesize Den-DC-G16-11-GCN5, a targeted nanomolecular probe for glioma. It’s to observe molecular imaging characteristics in glioma cell lines, blood-brain barrier biomimetic chips and mouse orthotopic transplantation models, and also to realize malignant evolution visualization and biological boundary determination of high-field MRI of glioma. This project is expected to obtain novel nano-imaging probes with good stability and high targeting in vivo. It will provide a new imaging method for determining the boundary of glioma, evaluating therapeutic effect and grading in vivo, and bringing a new way for accurate diagnosis and treatment of glioma. It has great scientific significance and potential application value.

胶质瘤演进机制复杂，恶性度高，侵袭性强，常规影像方法难以有效观测瘤周浸润性生长的肿瘤细胞，因此精准判定胶质瘤边界和浸润范围对于指导术中切缘有重要意义。体细胞水平上的基因突变是肿瘤重要特征，我们前期应用多组学分析对突变进行注释，筛选出GCN5并验证其在胶质瘤恶性演进中的驱动功能；病理学上我们发现瘤细胞清晰表达GCN5且与分级有关，而正常细胞不表达，因此GCN5可作为判定胶质瘤级别、区分肿瘤细胞浸润范围与边界的靶分子。本项目拟利用GCN5小分子抑制剂DC-G16-11，结合树枝状高分子Den合成胶质瘤的靶向纳米分子探针，观测其在胶质瘤细胞系、血脑屏障仿生芯片及小鼠原位移植瘤模型中的分子影像特征，实现胶质瘤高场MRI的恶性演进可视化与生物学边界判断。本项目有望获得体内稳定性好靶向性高的新型纳米成像探针，为活体判定胶质瘤边界、评估疗效与分级提供新的影像学方法，具有重大科学意义和潜在应用价值。

胶质瘤演进机制复杂，恶性度高，侵袭性强，常规影像方法难以有效观测瘤周浸润性生长的肿瘤细胞，因此精准判定胶质瘤边界对于指导术中切缘有重要意义。近年来随着分子影像技术迅猛发展，新的标志物不断被发现，建立病理特征-分子功能-影像信号间的互作关联，将使胶质瘤早期精准诊疗成为可能。课题组前期从胶质瘤活体组织病理表型差异出发，应用多组学技术对肿瘤细胞突变进行注释，筛选出GCN5并验证了其在胶质瘤恶性演进中的驱动功能。鉴于此，我们体外合成了GCN5特异性小分子抑制剂DC-G16-11并对其进行表征，进一步证实了该抑制剂可特异性结合GCN5抑制胶质瘤增值。因此，课题组选用树枝状高分子材料Den尺寸可控可修饰优点作为载体，结合荧光分子Cy5.5构建了形状均一、安全性高、生理稳定的Cy5.5-DEN-Gd-DC-G16-11探针，并在不同级别胶质瘤细胞、体外血脑屏障仿生模型以及动物模型中实验，证实该探针不仅可以高效通过血脑屏障，在MRI高磁场下成像，清晰显示肿瘤及肿瘤边界，实现肿瘤可视化，并能抑制肿瘤增值。具体结果如下：①探针在瘤体高度聚集，而正常脑组织无结合，清晰显示了肿瘤边界；②探针荧光强度与胶质瘤级别正向关，级别越高探针结合越多强度越高；③探针在体外血脑屏障仿生芯片通过率为25-40%，高于前期二氧化硅纳米探针的研究数据；④探针对小鼠重要器官如肝、肾、肠、肺、心脏、脑等无病理性损伤，可通过正常途径代谢；⑤探针修饰的小分子抑制对胶质瘤细胞增值与侵袭有明显抑制作用，与对照组比肿瘤缩小组织坏死且增值指数降低。. 综上，本项目通过纳米材料学、分子病理学与影像学的跨学科交叉融合，成功合成了一种体内稳定性好、靶向性高的新型诊疗多模态探针，为活体判定胶质瘤边界、肿瘤早诊、分级评估以及靶向治疗提供新的方法，达到了项目预期成果，具有重大科学意义和潜在应用价值。