磁性纳米粒蓄积诱导ROS激活自噬杀伤胶质瘤细胞的机制初探

Cross-linked nanoassemblies entrapping superparamagnetic iron oxide nanoparticles (CNA-IONPs) were developed in our team and showed their potential for MRI diagnosis and treatment of glioma. With the increase of CNA-IONPs exposure time at glioma sites, CNA-IONPs induced different ROS level and the effect of autophagy was changed from cell protection to cell death. p53 may play an important role in the regulation process. However, the two-way regulation mechanism of CNA-IONPs induced autophagy is still unknown. .CNA-IONPs induced ROS level will be investigated with the increase of exposure in glioma cell. The ROS induced protective autophagy or cell death effects will be explored. High ROS level-activated autophagy inducing autophagic cell death and apoptosis will be studied. The regulation effect of p53 on autophagic cell death will be investigated. siRNA p53 will be used to study whether high ROS level activates autophagy and leads to glioma cell death. A glioma rat model will be used to verify CNA-IONPs ROS induction, anti-glioma effect and the regulation mechanism of p53 to induce glioma cell death. .The goal of this study is to understand CNA-IONPs persistence stimulating ROS, inducing autophagy which leads to cell protection or cell death. This study will provide important information on CNA-IONPs as a potential nanomedicine for anti-glioma therapy.

申请人全新合成氧化铁交联胶束(CNA-IONPs)具有用于胶质瘤MRI诊断和治疗的潜力。在NIH资助下申请人发现CNA-IONPs在胶质瘤内随蓄积时间延长，诱导ROS升高, 引起自噬效应由肿瘤保护向杀伤转变，导致细胞死亡，p53在该过程中可能起到关键作用，但该转变机制尚未阐明。.本研究在胶质瘤细胞中观察由CNA-IONPs暴露时间差异产生不同水平ROS激活自噬，及其对细胞的保护/杀伤作用。确认高ROS激活自噬引起自噬性死亡和凋亡。研究p53对自噬启动癌细胞杀伤的作用。采用siRNA沉默验证p53是CNA-IONPs诱导高ROS激活自噬导致癌细胞杀伤的关键因子。在大鼠体内确证CNA-IONPs诱导ROS杀伤胶质瘤的作用，并初步验证p53调控自噬效应杀伤癌细胞的机制。.本项目旨在阐明CNA-IONPs在胶质瘤的蓄积诱导ROS升高激活自噬效应分化的机制，为其潜在抗胶质瘤临床应用提供实验依据。

纳米材料由于其小尺寸和高表面活性的特点，其潜在中枢神经系统蓄积、诊疗和毒性一直是纳米研究的重点。本研究首先从细胞水平精细确证氧化铁纳米颗在胶质瘤细胞暴露时间差异产生不同水平ROS。低水平ROS诱导细胞自噬起到保护胶质瘤细胞作用；高水平ROS诱导自噬促进细胞死亡(自噬性死亡和凋亡)起到抗胶质瘤效果。深入阐明在高水平ROS环境中，氧化铁纳米颗诱导ROS, 诱导自噬性死亡和凋亡的分子机制。从整体动物水平证明氧化铁纳米颗有体内长时间蓄积的特点，且不同蓄积时间诱导靶器官产生多极化氧化应激。确证氧化铁纳米颗粒长时间蓄积诱导ROS相关靶器官细胞自噬性死亡和凋亡。进一步利用体外血脑屏障培养体系和体内血脑屏障评价纳米银颗粒对血脑屏障通透和功能的影响，评价其潜在进入中枢神经系统的风险。利用电子显微镜观察中枢神经系统超微结构变化和纳米颗粒在中枢神经系统的分布，揭示了纳米银颗粒进入中枢神经系统的潜在风险。最后基因表达谱的变化显示纳米银颗粒对中枢神经系统细胞凋亡、海马区学习记忆等功能产生影响。以上研究结果为开发纳米颗粒的中枢神经体统应用和评价潜在中枢神经体统毒性奠定了坚实的理论基础。