^(99)Tc^m-RGD环肽二聚体的制备及其体内外评价  

Preparation of ^(99)Tc^m labeled cyclic RGDfK dimer and its in vitro and in vivo evaluation

作　　者：刘昭飞[1] 贾兵[1] 史继云[1] 杨志[2] 赵慧云[1] 王凡[1] 

机构地区：[1]北京大学医学同位素研究中心,100083 [2]北京大学临床肿瘤学院核医学科

出　　处：《中华核医学杂志》2007年第4期205-209,共5页Chinese Journal of Nuclear Medicine

基　　金：北京市科技计划项目(Z00004105040311)

摘　　要：目的评价^(99)Tc^m 标记的精氨酸-甘氨酸-天冬氨酸(RGD)环肽二聚体 E[c(RGDfK)]_2的体内外特性及其用于整合素α_vβ_3阳性肿瘤显像的可行性。方法以三羟甲基甘氨酸(tricine)和三苯基膦三磺酸钠(TPPTS)作为协同配体,以联肼尼克酰胺(HYNIC)作为双功能连接剂,采用无亚锡一步法制备^(99)Tc^m-HYNIC-E[c(RGDfK)]_2,通过 U87人神经胶质瘤细胞测定其半数抑制浓度(IC_(50)),观察其体外与整合素α_vβ_3受体的结合解离动力学、细胞内化及外化,评价其在荷人神经胶质瘤裸鼠的生物分布。结果 ^(99)Tc^m-HYNIC-E[c(RGDfK)]_2的标记率>95%,经 Sep-Pek C18柱纯化后其放化纯>99%。与 RGD 环肽单体 c(RGDyK)相比,HYNIC 偶联的 E[c(RGDfK)]_2二聚体具有更高的整合素α_vβ_3亲和力,IC_(50)分别为80.0和9.07 nmol/L。细胞实验显示,^(99)Tc^m-HYNIC-E[c(RGDfK)]_2与整合素α_vβ_3结合较快,并迅速被受体介导内化。生物分布实验显示,^(99)Tc^m-HYNIC—E[c(RGDfK)]_2主要经肾脏排泄,在注射后0.5和4 h,标记物在肿瘤的每克组织百分注射剂量率(%ID/g)分别为(2.46±0.66)和(3.10±0.35)%ID/g,标记物在肿瘤中的滞留时间足够长。γ显像示注射后1 h 肿瘤清晰可见,注射后4 h 显像效果更佳。结论 ^(99)Tc^m-HYNIC-E[c(RGDfK)]_2是一种有前景的用于整合素α_vβ_3阳性肿瘤显像的显像剂。Objective Peptides labeledwith radionuclides such as ^99Tc^m as the tumor imaging agents induced interests among scientists with some studies published. The aim of this study was to evaluate the in vitro and in vivo characteristics of ^99Tc^m labeled cyclic RGDfK dimer E [ c（RGDfK） ] 2 for imaging integrin α,β3-positive tumors. Methods ^99 Tc^m-hydrazino-nicotinamide （ HYNIC ） E- [ c （ RGDfK ） ] 2 was prepared by one step method without SnC12, while tricine and trisodium triphenylphosphine-3,3＇ ,3＂-trisulfonate （TPPTS） were chosen as eoligands, and HYNIC as chelator. The concentration of 50% inhibition （ IC50 ） was determined on U87 human glioma cells. The in vitro receptor binding and disassociation kinetics, cell internalization and effiux were investigated. The biodistribution and γ imaging were performed in nude mice bearing human glioma xenografts. Results The labeling yield of ^99Tc^m-HYNIC-E[ c（RGDfK） ] 2 was over 95% , and the radiochemical purity was more than 99% after the purification with Sep-Pek C18 cartridge. Comparing to c （RGDyK） monomer, HVNIC-conjugated E[c （RGDfK） ] 2 dimer possessed a significantly higher integrin ctv133 binding affinity with the IC50 of 80. 0 and 9. 07 nmol/L, respectively. Cell experiments showed that ^99Tc^m-HYNIC-E [ c （RGDfK） ] 2 rapidly bonded to integrin ct, 133 before internalized by receptor-mediated way. Biodistribution data showed that ^99Tc^m-HYNIC-E [ c （RGDfK）] 2 was excreted mainly through kidneys, and the uptake of tumors （ percentage activity of injection dose per gram of tissue, % ID/g） at 0.5 and 4 h postinjeetion was （2.46 ± 0.66） and （3.10 ±0.35 ） % ID/g, respectively, suggesting a long enough retention time. γ imaging clearly revealed xenografted tumors at 1 h postinjection, but the images at 4 h were better. Condusion ^99Tc^m-HYNIC-E[ c（RGDfK） ]2 is a promising radiotracer for integrin α,β3-positive tumor imaging.

关 键 词：肽类 锝 同位素标记 药代动力学 放射性核素显像 肿瘤细胞 培养的 小鼠 裸 

分 类 号：R817[医药卫生—影像医学与核医学]