自组装铁基纳米载体可视化递送p53基因多途径治疗三阴乳腺癌的研究

Clinical treatment of triple negative breast cancer (TNBC) mainly relies on chemotherapy, which is lack of specific treatment program. In our preliminary experiment, we found TNBC tumor tissue contains a large amount of TNBC stem cells. Moreover, TNBC cells and TNBC stem cells have a weak endurance to oxidative stress and therefore sensitive to ferroptosis, which can be activated by p53 gene and induced by iron dependent oxidative stress. Based on these, we designed self-assemble iron-based p53 nanocarriers for TNBC treatment. In this structure, the ultrasmall Fe3O4 nanoparticles have strong T1 weighted imaging signal, while the assembled nanocarriers have larger size, making them good T2 weighted imaging candidates. This phenomenon can be used to conduct the visual trace of the nanocarriers. This project intends to carry out in vitro and vivo experiments, combining with the clinical data to study the function of IO-5@p53. The goals of this project are: 1) To identify the molecular function and mechanism which are how IO-5@p53 induce the ferroptosis of TNBC stem cells; 2) To reveal the relationship between ferroptosis and magnetic transfection of p53 as well as the nanozyme property of IO-5; 3) To confirm that IO-5@p53 can induce tumor associated macrophages (TAMs) to differentiate into the anti-tumor M1 type, and consequently inhibit the epithelial-mesenchymal transition (EMT) and formation of TNBC stem cells; 4) To thoroughly illustrate the actual molecular mechanisms that IO-5@p53 influence the functions of the cells via regulating their oxidative stress. This project is expected to provide experimental research foundation for revealing the relevance of the chemical properties of nanozymes and their antitumor mechanism, and it is expected to provide new target and method to the treatment of TNBC.

三阴性乳腺癌（TNBC）临床单以化疗为主，缺乏针对性的治疗方案。我们前期发现：TNBC及其富含的TNBC干细胞对“铁死亡”这种可由p53启动的铁依赖氧化应激死亡模式敏感。基于此，我们构建了自组装铁基p53纳米载体（IO-5@p53），其中超小氧化铁IO-5具T1造影能力，自组装后尺寸增加而具备强T2信号，可通过MRI动态监控pH响应的解聚过程。项目将通过一系列体内外实验并结合临床数据，明确IO-5@p53诱导TNBC干细胞铁死亡的分子功能及机制；解析铁死亡与IO-5@p53磁转染效率及纳米酶效应之间的关联；确证IO-5@p53诱导TAMs向M1型分化，从而抑制TNBC细胞上皮间质转化（EMT）及干性演变的功能；深入阐述IO-5@p53通过调控细胞氧化应激水平影响细胞功能的确切分子机制。本项目为揭示铁基纳米酶的化学性能和抗癌机制的关系提供实验基础，有望为TNBC的治疗提供新靶点、新思路。

三阴乳腺癌（TNBC）是一种特殊亚型的高侵袭性乳腺癌，相比于其他亚型，具有常规治疗疗效差、预后差、复发耐药率高、总体生存率低的特点。当前，患者的中位生存时间（OS）鲜有超过12-18个月，该类患者不能从抗ER、PR内分泌治疗或抗HER-2的靶向治疗中获益，因此细胞毒类化疗作为TNBC治疗主要药物治疗手段，但患者化疗的总体缓解率仍然偏低。本项目构建了系列c(RGDyk)、D-氨基葡萄糖接枝的以及pH响应的铁基纳米载体（Fe3O4@RGD@GLU，Fe3O4-cRGD-αCD-CH3O-PEG-PEI）。它由5-30nm的磁性纳米铁核和生物相容的PEG2000壳组成，可特异性靶向肿瘤血管和癌细胞。选择c(RGDyk)使该类载体可通过αvβ3介导的内吞作用进入新生血管的内皮细胞。同时利用外加磁力的导向作用、纳米材料的EPR效应以及表面修饰的RGD抗体，使铁基纳米载体高效靶向到三阴乳腺癌，实现基因的磁性转染，并诱导三阴乳腺癌及其干细胞铁死亡。另外，研究通过将青蒿素与铁基纳米颗粒联用，产生了乳腺癌干细胞的显著杀伤效果，得出青蒿素具有诱导乳腺癌干细胞“铁死亡”的作用，青蒿素通过调控“铁死亡”通路来调控肿瘤干细胞的干性和活力。进一步得出青蒿素与铁基纳米颗粒联用会产生Fenton效应，并增加青蒿素对乳腺癌干细胞“铁死亡”的作用，铁基纳米颗粒自身也具有产生活性氧（ROS）的性能，加强了乳腺癌干细胞“铁死亡”作用。项目执行期间共完成相关的论文7篇，申请发明专利10项，目前已经获得授权的5项，同时辅助带教研究生6名。本项目的完成是以坚实临床研究为背景，为铁基纳米材料的产业化和临床应用做出了一定贡献，有望推动纳米医学学科的发展。