Background and Purpose:Glioblastoma remains a therapeutic challenge with a poor prognosis despite multimodal treatments. Reporter-based magnetic resonance imaging (MRI) offers a promising approach for tumor visualization, but its efficacy depends on sufficient reporter gene expression. This study aimed to develop a chimeric element-regulated ferritin heavy chain 1 (FTH1) reporter system to enhance MRI-based glioma detection while enabling targeted therapy via transferrin receptor (TfR)-mediated drug delivery.Methods:Using gene cloning techniques, we constructed a chimericFTH1expression system comprising tumor-specificPEG3promoter (transcriptional control),bFGF-2 5′UTR(translational enhancement), andWPRE(mRNA stabilization). Lentiviral vectors delivered constructs to U251 glioblastoma cells and xenografts. FTH1/TfR expression was validated by Western blot and immunofluorescence. Iron accumulation was assessed via Prussian blue staining and TEM. MRI evaluated T2 signal changes. Transferrin-modified doxorubicin liposomes (Tf-LPD) were characterized for size and drug loading and tested for cellular uptake and cytotoxicity in vitro. In vivo therapeutic efficacy was assessed in nude mouse models through tumor volume measurement, MR imaging, and histopathology.Results:The chimeric system increasedFTH1expression significantly over PEG3-only controls (p< 0.01), with an increase of nearly 1.5-fold compared to the negative and blank groups and approximately a two-fold increase relative to the single promoter group, with corresponding TfR upregulation. Enhanced iron accumulation reduced T2 relaxation times significantly (p< 0.01), improving MR contrast. Tf-LPD (115 nm, 70% encapsulation) showed TfR-dependent uptake, inducing obvious apoptosis in high-TfR cells compared with that in controls. In vivo, Tf-LPD reduced tumor growth markedly in chimeric-system xenografts versus controls, with concurrent MR signal attenuation.Conclusions:The chimeric regulatory strategy overcomes limitations of single-element systems, demonstrating significant potential for integrated glioma theranostics. Its modular design may be adaptable to other reporter genes and malignancies.
**背景与目的：** 胶质母细胞瘤即使采用多模式治疗，预后仍然较差，是当前治疗的难点。基于报告基因的磁共振成像（MRI）为肿瘤可视化提供了有前景的方法，但其效果取决于报告基因的充分表达。本研究旨在开发一种嵌合元件调控的铁蛋白重链1（FTH1）报告系统，以增强基于MRI的胶质瘤检测能力，同时通过转铁蛋白受体（TfR）介导的药物递送实现靶向治疗。 **方法：** 利用基因克隆技术，我们构建了一个嵌合FTH1表达系统，包含肿瘤特异性PEG3启动子（转录调控）、bFGF-2 5′UTR（翻译增强）和WPRE（mRNA稳定化元件）。通过慢病毒载体将构建体递送至U251胶质母细胞瘤细胞及移植瘤模型。采用Western blot和免疫荧光验证FTH1/TfR的表达。通过普鲁士蓝染色和透射电镜评估铁积累情况。MRI检测T2信号变化。制备并表征转铁蛋白修饰的阿霉素脂质体（Tf-LPD）的粒径和载药量，并在体外测试其细胞摄取和细胞毒性。在裸鼠模型中，通过肿瘤体积测量、MR成像和组织病理学评估体内治疗效果。 **结果：** 与仅含PEG3启动子的对照组相比，嵌合系统显著提高了FTH1表达（p < 0.01），较阴性组和空白组增加近1.5倍，较单启动子组增加约2倍，同时伴随TfR上调。增强的铁积累显著降低了T2弛豫时间（p < 0.01），改善了MR对比度。Tf-LPD（粒径115 nm，包封率70%）表现出TfR依赖性摄取，与对照组相比，在高TfR细胞中诱导明显的细胞凋亡。在体内实验中，与对照组相比，Tf-LPD在嵌合系统移植瘤中显著抑制肿瘤生长，并伴随MR信号减弱。 **结论：** 嵌合调控策略克服了单元件系统的局限性，显示出在胶质瘤诊疗一体化方面的巨大潜力。其模块化设计可能适用于其他报告基因及恶性肿瘤。
Chimeric Element-Regulated MRI Reporter System for Mediation of Glioma Theranostics
肿瘤(癌症)患者之家