99mTc标记PD-L1纳米抗体用于荷非小细胞肺癌模型SPECT/CT显像  

99mTc-Labeled PD-L1 nanobody for SPECT/CT imaging of non-small cell lung cancer

作　　者：赵凌舟[1] 邢岩[1] 刘长存[1] 郭李磊 乔文礼[1] 赵晋华[1] ZHAO Lingzhou;XING Yan;LIU Changcun;GUO Lilei;QIAO Wenli;ZHAO Jinhua(Department of Nuclear Medicine,Shanghai General Hospital,Shanghai Jiao Tong University School of Medicine,Shanghai 200080,China)

机构地区：[1]上海交通大学附属第一人民医院核医学科

出　　处：《肿瘤影像学》2019年第4期216-222,共7页Oncoradiology

基　　金：上海申康医院发展中心促进市级医院临床技能与临床创新三年行动计划（16CR3052A）

摘　　要：目的:使用放射性核素99m Tc标记程序性死亡受体-配体1(programmed cell death-ligand 1,PD-L1)纳米抗体,制备靶向非小细胞肺癌(non-small cell lung cancer,NSCLC)的显像剂(99mTc-PD-L1纳米抗体),评价其在SPECT/CT上显示肿瘤PD-L1表达的可行性。方法:采用三羰基化合物试剂盒制备标记前体三羰基锝化合物盐溶液,标记PD-L1纳米抗体,并测定标志物的标记率、放射化学纯度及体外稳定性;分别构建PD-L1高表达(HCC827)和PD-L1阴性(A549)的 NSCLC裸鼠移植瘤模型,经尾静脉注射99mTc-PD-L1纳米抗体30、90 min后,观察和分析SPECT/CT显像。结果:99mTc-PD-L1纳米抗体的标记率在95%以上,且在磷酸盐缓冲液(phosphate buffered saline,PBS)和血清中均表现良好的稳定性。小动物SPECT/CT显像表明99mTc-PD-L1纳米抗体在PD-L1高表达组中具有良好的肿瘤摄取,而在PD-L1阴性组无明显肿瘤摄取,表明99mTc-PD-L1纳米抗体能够显示肿瘤PD-L1的表达情况,具有良好的体内特异性;此外,99mTc-PD-L1纳米抗体主要分布在肾脏,通过泌尿系统排泄,肝脏、脾脏、心脏、肺及软组织等显影微弱,甲状腺区及胃肠未见核素浓聚,证实显像剂具有良好的生物分布。结论:该研究利用三羰基化合物试剂盒成功制备了99mTc-PD-L1纳米抗体,标志物具有良好的标记率和体外稳定性,能够在PD-L1高表达的NSCLC中特异性浓聚,有潜力成为一种新型的显示肿瘤PD-L1表达的显像剂。Objective: In this study, 99mTc-labeled PD-L1 nanobody was prepared and its potential as a SPECT/CT imaging agent for the visualization of tumor PD-L1 expression was performed via a xenograft nude mouse model. Methods: The PD-L1 nanobody was radiolabeled with 99mTc(CO)3(H2O)3. The radiolabeling yields and stabilities were studied by radio-active instant thin layer chromatography (radio-ITLC) and high performance liquid chromatography (HPLC). Micro-SPECT/CT imaging was performed at 30, 90 min after intravenous injection of 99mTc-PD-L1 nanobody in HCC827 and A549 as PD-L1 expression positive and negative groups, respectively. Results: The radiochemical yield of 99mTc-PD-L1 nanobody was above 95%, and was stable within 3 h both in phosphate buffered saline (PBS) and human serum at 37℃. SPECT images of 99mTc-PD-L1 nanobody in tumor models showed that HCC827 tumor lesions were visualized with high contrast at 30, 90 min post-injection, while no obvious radioactive signal could be found in A549 tumor lesions, suggesting that the formed 99mTc-PD-L1 nanobody could show the PD-L1 expression in tumors and had favorable specificity in vivo. Moreover, the 99mTc-PD-L1 was mainly accumulated in kidneys and eliminated from the body through urinary system, while other tissues, including liver, spleen, heart, lung and soft tissues, displayed low accumulation and no obvious radioactivity was found in thyroid and gastrointestinal system, indicating the beneficial biodistribution of 99mTc-PD-L1. Conclusion: 99mTc-PD-L1 nanobody was successfully prepared with a high radiochemical purity and stability, and could be used as a tumorspecific ligand for SPECT imaging of tumor PD-L1 expression.

关 键 词：程序性死亡受体-配体1 纳米抗体 非小细胞肺癌 锝-99m 小动物SPECT/CT显像 

分 类 号：R734.2[医药卫生—肿瘤] R445.6[医药卫生—临床医学]