Small interference RNA (siRNA) was radiolabeled by using the bifunctional chelator of NHS-MAG3 and SnCl2 · 2H2O. After transfected into Hepatocarcinoma HepG2 cells, labeled and unlabeled hTERT-targeted siRNA had the similar inhibitory rate about 76.7％ measured by western blotting method. In the biodistribution study, the radioactive accumulation was primarily found in the kidneys, and then in liver. The radioactivity of hTERT-targeted siRNA in tumor increased from (0. 82 ± 0. 16) ％ID/g to (0.97 4±0.15) ％ID/g from I to 6 hours after the administration. The uptake ratio of tumor to blood and tumor to muscle were 2.62 ± 0.70 and 6.02 ± 0.52, respectively, significantly higher than that of the control group (P＜0.05). These results indicated that 99Tcm radiolabeled hTERT-targeted siRNA allows for prospective future and potential application value in the noninvasive visualization of tumor telomerase in vivo.%使用双功能螯合剂NHS-MAG3和氯化亚锡还原法构建99Tcm标记的小干扰RNA(Small Interference RNA,siRNA)探针.将标记和未标记的端粒逆转录酶(Human Telomerase Reverse Trancriptase,hTERT)靶向siRNA转染至肝癌HepG2细胞,72 h后,蛋白印迹法显示两者具有相近的蛋白抑制率(约76.7%).标记物在荷HepG肿瘤裸鼠体内的生物分布显示,肾脏分布最高,其次为肝脏.注射hTERT靶向探针后1～6 h内,肿瘤分布由(0.82±0.16)%ID/g增加至(0.97±0.15)%ID/g,肿瘤与血液和肿瘤与肌肉的放射性摄取比(T/NT)分别为2.62±0.70和6.02±0.52,显著高于对照组(P＜0.05).以上结果提示,99Tcm-siRNA探针对活体肿瘤示踪具有良好的研究前景和潜在的应用价值.
展开▼
