99Tcm标记新型RGD环肽在神经胶质瘤动物模型的实验研究  

Imaging of 99Tcm-labeled new cyclic RGDfK Dimer in nude mice bearing U87MG human glioma xenografts

作　　者：靳晓娜[1] 史继云[2] 刘妍[2] 朱朝晖[1] 贾兵[2] 刘昭飞[2] 石希敏[1] 王凡[2] 李方[1] 

机构地区：[1]北京协和医学院、中国医学科学院北京协和医院核医学科,100730 [2]北京大学医学同位素研究中心

出　　处：《中华核医学杂志》2010年第3期195-200,共6页Chinese Journal of Nuclear Medicine

基　　金：基金项目：国家自然科学基金（30670741）

摘　　要：目的 评价引入2个聚乙二醇（PEG4）对精氨酸-甘氨酸-天冬氨酸（RGD）环肽二聚体（Dimer：E[c（RGDfK）]2）体外受体结合亲和力和体内药代动力学特征的影响,以及99Tcm标记2PEG4-Dimer用于整合素αvβ3阳性肿瘤显像的前景.方法 用免疫组织化学实验测定U87MG人神经胶质瘤细胞以及肿瘤组织中整合素αvβ3的表达.通过U87MG细胞受体竞争结合实验测定RGD环肽单体c（RGDyK）、联肼尼克酰胺（HYNIC）-Dimer和HYNIC-2PEG4-Dimer对125I-c（RGDyK）的半数抑制浓度（IC50）.采用无亚锡一步法制备99Tcm-HYNIC-Dimer和99Tcm-HYNIC-2PEG4-Dimer,评价＂TcmHYNIC-2PEG4-Dimer在荷U87MG瘤裸鼠的生物分布并进行γ显像.采用非配对t检验法对实验数据进行分析.结果 U87MG细胞和荷瘤裸鼠肿瘤组织中高表达整合素αvβ3.HYNIC-2PEG4-Dimer比c（RGDyK）和HYNIC-Dimer有更高的整合素αvβ3亲和力（IC50分别是0.8,27和2.4 nmol/L）.99Tcm-HYNIC-Dimer和99Tcm-HYNIC-2PEG4-Dimer的99Tcm标记率均＞95%,经Sep-Pek C18柱纯化后其放化纯＞99%.生物分布实验显示,2种标记物均主要经肾排泄,在注射后2h,肿瘤对99Tcm-HYNIC-2PEG4-Dimer的摄取为99Tcm-HYNIC-Dimer的2.7倍[（5.71±0.96）%ID/g和（2.10±0.50）%ID/g],t=4.80,P＜0.05,与体外受体竞争结合实验数据相一致.γ显像结果显示,注射99Tcm-HYNIC-2PEG4-Dimer后0.5 h肿瘤即清晰可见,随时间延长,体内放射性本底明显减低,显像对比度增高.结论 99Tcm-HYNIC-2PEG4-Dimer有希望用于整合素αvβ3阳性肿瘤显像.Objective （1） To evaluate the effect of insertion of two 15-amino-4,7,10,13-tetraoxapentadecanoic （2 PEG4 ） linkers into cyclic Arg-Gly-Asp （RGD） Dimer E [c（RGDfK）]2 on receptor binding in vitro, （2） to assess its biodistribution in vivo and （3） to investigate the value of 99Tcm labeled 2PEG4-Dimer for integrin αvβ3-positive tumors imaging.Methods The expression of U87 human glioma cells and integrin αv β3 was determined by immunofluorescence staining.The half-inhibition concentrations （IC50） for 125 I-cyclo （Arg-Gly-Asp-D-Tyr-Lys） （c（RGDyK） ） of c （ RGDyK ）, hydrazinonictinamide （ HYNIC ）-Dimer and HYNIC-2PEG4-Dimer binding to integrin αvβ3 were measured.99Tcm-HYNIC-Dimer and 99Tcm-HYNIC-2PEG4-Dimer were synthesized using non-SnCl2 formulation.Biodistribution and imaging studies were performed in nude mice bearing human glioma xenografts.The unpaired t test was used for statistical analysis.Results The labeling yield of the two radiotracers was more than 95%, and the radiochemical purity was more than 99% through Sep-Pek C18 cartridge.HYNIC-2PEG4-Dimer had significantly higher binding affinity of integrin αvβ3 than c（RGDyK） and HYNIC-Dimer （IC50 = 0.8 nmol/L, 27 nmol/L and 2.4 nmol/L, respectively）.Biodistribution study showed that 99Tcm-HYNIC-2PEG4-Dimer was mainly excreted via the kidney.The tumor uptake of 99Tcm-HYNIC-2PEG4-Dimer was higher than that of 99Tcm-HYNIC-Dimer at 2h post injection （（5.71 ±0.96） and （2.10 ±0.50） % ID/g, t =4.80, P〈0.05）.The xenografted tumors were visible at 0.5 h post injection and the image contrast increased with time due to the tracer clearance of the background tissue.Conclusion 99 Tcm-HYNIC-2PEG4-Dimer is a promising radiotracer for integrin αvβ3-positive tumor imaging.

关 键 词：肽类 环 锝 整合素αvβ3 神经胶质瘤 放射性核素显像 小鼠 裸 

分 类 号：R739.41[医药卫生—肿瘤]