标记hATF的超顺磁性氧化铁纳米颗粒探针在结肠癌肿瘤模型中的分子影像

发布时间：2018-04-08 09:54

本文选题：尿激酶型纤溶酶原激活物受体　切入点：分子影像　出处：《生物医学工程学杂志》2015年05期

【摘要】：尿激酶型纤溶酶原激活物受体(uPAR)是细胞外膜蛋白。uPAR不仅在恶性肿瘤细胞中表达明显增高,同时在肿瘤间质中也表达增强。本研究将uPAR作为分子靶点,以人类氨基末端片段(hATF)作为靶向原件标记超顺磁性氧化铁纳米颗粒(SPIO),利用该靶向探针在uPAR中度表达的HT29荷瘤裸鼠体内验证该探针的影像效能。体外通过流式细胞术检测细胞uPAR表达量,普鲁士蓝染色以及细胞MRI扫描检测探针的特异性,MRI扫描荷瘤裸鼠检测探针体内的成像效能,并通过病理学检查显示探针在肿瘤内分布情况。结果显示,不同肿瘤细胞具有不同uPAR表达特性,在筛选的细胞系中,Hela为uPAR强阳性细胞,HT29为uPAR中度阳性细胞,Lovo则为uPAR阴性细胞。体外试验利用强表达uPAR的Hela细胞与hATF-SPIO探针共同孵育,通过普鲁士蓝染色及MRI细胞扫描发现,hATF-SPIO能够特异性结合Hela细胞且使得其T2WI信号明显减低;而对照组Lovo细胞MRI信号值在探针孵育前后未见明显变化,普鲁士蓝染色也未见hATF-SPIO在Lovo细胞中的滞留。MRI动物扫描显示hATF-SPIO探针能够随着血流达到HT29移植瘤且使得HT29肿瘤在T2加权相上较Lovo移植瘤信号降低,在探针注入后24h,两者信号值有明显差异;随后肿瘤组织的普鲁士蓝染色观察显示hATF-SPIO探针在HT29移植瘤内存留。综上所述,通过实验证明hATF-SPIO不仅在体外能够靶向结合uPAR表达的肿瘤细胞,并能够在体内靶向显影uPAR中度表达的结肠肿瘤。
[Abstract]:Urokinase-type plasminogen activator receptor (UPAR) is an extracellular membrane protein. Upar is not only expressed significantly in malignant tumor cells, but also in tumor stroma.In this study, uPAR was used as a molecular target and human amino terminal fragment hATF was used as the original target to label superparamagnetic iron oxide nanoparticles. The target probe was used to test the imaging efficacy of the probe in nude mice with moderate expression of HT29.UPAR expression was detected by flow cytometry in vitro, Prussian blue staining and MRI scanning were used to detect the imaging efficiency of the probe in nude mice.The distribution of the probe in the tumor was demonstrated by pathological examination.The results showed that different tumor cells had different uPAR expression characteristics. In the selected cell lines, Hela was a strong positive uPAR cell line and HT29 was a moderately positive uPAR cell. Lovo was a uPAR negative cell.In vitro, Hela cells with strong expression of uPAR were incubated with hATF-SPIO probe. By Prussian blue staining and MRI cell scanning, it was found that hATF-SPIO could specifically bind Hela cells and reduce T2WI signal.However, the MRI signal of Lovo cells in the control group did not change significantly before and after incubation with the probe.The presence of hATF-SPIO in Lovo cells was also not observed by Prussian blue staining. MRI animal scanning showed that the hATF-SPIO probe was able to reach HT29 transplanted tumor with blood flow and the signal intensity of HT29 tumor on T2 weighted phase was lower than that of Lovo transplanted tumor.There was significant difference in the signal values between the two groups 24 hours after the injection of the probe, and then the Prussian blue staining of the tumor tissue showed that the hATF-SPIO probe remained in the memory of the HT29 transplanted tumor.To sum up, hATF-SPIO can target not only tumor cells with uPAR expression in vitro, but also colon tumors with moderate uPAR expression in vivo.
【作者单位】：四川大学华西医院肿瘤中心;四川大学华西医院分子影像中心;四川大学华西医院放射科;
【基金】：国家973研究计划资助项目(2011CB935800)
【分类号】：R735.35;R445.2

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