基于诱导细胞Ferroptosis的智能分子探针及其可视化靶向治疗恶性肿瘤的实验研究

Apoptosis plays a critical role in the traditional cancer therapy. However, it has been challenged by apoptosis resistance. Ferroptosis, an iron-dependent form of non-apoptotic cell death, can evade the apoptotic resistance. Therefore, the strategy that induces this type of cell death holds great therapeutic potential and provides new opportunities for cancer treatments. In this study, a smart tumor-responsive molecular probe based on mesoporous Fe3O4 nanoparticles, loaded with p533KR mutated plasmid and NRF2 inhibitor trigonelline (TRI) and covalently conjugated with bifunctional reporter [18F]BODIPY, will be fabricated to eradicate cancer cells via ferroptotic pathway. After internalized by cancer cells, the probe is located at the acidic and glutathione compartments of endosomes and lysosomes, releasing Fe2+ ions, trigonelline and p533KR plasmid to inside the cytoplasm. The excess accumulation of intracellular Fe2+ ions leads to the reactive oxygen species (ROS) generation upon Fenton chemistry and the lipid peroxidation (LPO) in biomembranes. Meanwhile, by harnessing the recently discovered oxidative stress regulation ability of p533KR, the probe can maximize the intracellular LPO level to kill cancer cells via intracellular oxidative stress-dependent ferroptosis pathway. Subsequently, the characteristics and mechanism of ferroptosis induced by the probe are thoroughly analyzed by molecular biological technologies in vitro. Furthermore, PET/NIRF imaging and therapeutic study are performed in tumor-bearing mice to demonstrate a proof-of-principle trail for in vivo application. This study may present a theranostic platform based on nanomaterials with great potential in ferroptosis-based cancer therapy guided by dual-modality PET/NIRF imaging, which will provide new ideas for the innovative development of molecular probes and provide new perspectives for cancer diagnosis and treatment.

凋亡抵抗对传统肿瘤防治理念提出新挑战。Ferroptosis是完全不同于凋亡的铁依赖性细胞死亡模式，通过定向诱导发生该类型死亡，可绕过细胞凋亡途径而更好杀死肿瘤细胞，为抗肿瘤治疗提供新机遇。本项目拟利用介孔氧化铁纳米材料，通过有效结合p533KR突变质粒、NRF2抑制剂TRI和双功能信号组件[18F]BODIPY，构建新型智能分子探针；利用纳米材料表面效应，巧妙实现肿瘤内环境触发下的Fe2+、p533KR和TRI定点释放，协同诱导Ferroptosis发生；依托现代分子生物学技术，在分子和细胞水平上研究智能分子探针诱导肿瘤细胞Ferroptosis的特性，并探究其分子机制；依托整体动物模型和分子影像技术，在活体水平上进行PET/NIRF双模态显像和肿瘤治疗研究，明确新型智能分子探针可视化靶向治疗恶性肿瘤的特异性和敏感性。该研究可为分子探针的创新研制提供新思路，为恶性肿瘤诊疗提供新视角。

Ferroptosis是一种完全不同于细胞凋亡、自噬和坏死的铁依赖性细胞死亡方式，有望成为肿瘤治疗的新靶点。如何将多种干预因子同时靶向递送至肿瘤细胞内，协同高效诱导Ferroptosis发生，是目前尚未解决的关键科学问题。在良好前期研究基础上，本项目通过结构调控和性能优化，成功将主动靶向、基因/药物递送、智能激活、可视化等模块融入纳米平台，构筑智能分子探针mFe3O4-TRI/p53、Fe(III)-ART 和GOD@CaCO3-Fe3O4；在体外，从材料学、理化特征和智能激活着手，确证了智能分子探针的结构和功能；在细胞水平，从形态学和生化特征着手，明确了智能分子探针诱导肿瘤细胞Ferroptosis的特异性和敏感性；在分子水平，从铁负荷、SLC7A11/GSH/GPX4信号轴和NRF2抗氧化通路着手，初步验证了智能分子探针多点调控Ferroptosis信号通路的作用机制；在动物模型中，通过预定位PET/MRI/NIRF多模态显像和肿瘤治疗研究，证实了智能分子探针可视化靶向治疗恶性肿瘤的可行性和实效性。项目执行以来，围绕“定向诱导细胞Ferroptosis”这一核心思想，按照研究计划完成研究内容探索，实现了预期研究目标。本项目的顺利实施，为构建以Ferroptosis为靶点的诊疗一体化智能药物和肿瘤防治新方法提供了良好理论基础和科学依据。