构建肿瘤免疫治疗PD-L1靶向PET分子探针^68Ga-NOTA-WL12及生物学观察  

Preparation of PET molecular probe^68Ga-NOTA-WL12 targeting PD-L1 for tumor immunotherapy

作　　者：蒋金泉 李丹[2] 刘特立 夏雷 徐晓霞 郭晓轶 朱华[2] 杨志[2] JIANG Jinquan;LI Dan;LIU Teli;XIA Lei;XU Xiaoxia;GUO Xiaoyi;ZHU Hua;YANG Zhi(Department of Radiology,Peoples'Hospital of Deyang City,Deyang 618000,China;Department of Nuclear Medicine,Peking University Cancer Hospital&Institute,Key Laboratory of Carcinogenesis and Translational Research,Beijing 100142,China)

机构地区：[1]德阳市人民医院放射科,四川德阳618000 [2]北京大学肿瘤医院暨北京市肿瘤防治研究所核医学科,恶性肿瘤发病机制及转化研究教育部重点实验室,北京100142

出　　处：《中国医学影像技术》2021年第1期8-12,共5页Chinese Journal of Medical Imaging Technology

基　　金：国家自然科学基金(81401467、81731592)。

摘　　要：目的构建程序性细胞死亡受体1(PD-1)靶向^68Ga-NOTA-WL12分子探针,观察其生物分布,评价可否用于检测肿瘤PD-L1表达。方法在60℃、pH 4.5条件下,以放射性核素^68Ga标记多肽分子NOTA-WL12,利用放射性薄层色谱扫描仪(Radio-TLC)测定反应产物标记率。以活化C18柱对原始反应产物进行纯化并获得终产物,分析其放射化学纯度。以0.9%生理盐水及5%人血白蛋白(HSA)分析该分子探针的体外稳定性,并以脂水分布实验观察其分布。向正常雌性昆明鼠体内注射1.11 MBq^68Ga-NOTA-WL12,分别于其后5、30、60、120及240 min观察其体内分布。建立PD-1配体(PD-L1)表达阳性CHO-hPD-L1肿瘤模型和PD-L1表达阴性MDA-MB-231肿瘤模型,以小动物PET/CT显像观察该分子探针在体分布代谢,评价其可否用于检测肿瘤病灶内PD-L1表达。对CHO-hPD-L1肿瘤模型鼠行共注射阻断实验,观察肿瘤病灶摄取。结果^68Ga-NOTA-WL12分子探针标记率>95%,放射化学纯度>98%,体外稳定性良好;生物分布观察及PET/CT显像显示其主要通过肝肾代谢,肝肾存在非特异性摄取。注射后肿瘤病灶分子探针摄取先逐渐增高,后明显降低。结论^68Ga-NOTA-WL12体外稳定性良好,并能特异性地在小鼠模型PD-L1阳性肿瘤组织中浓聚。Objective To construct a programmed death 1(PD-1)targeted^68Ga-NOTA-WL12 molecular probe,and to observe its biological distribution and the ability to detect tumor PD-L1.Methods Under the condition of 60℃and pH4.5,NOTA-WL12 was labeled by radionuclide^68Ga,and the labeling rate of the reaction product was determined with Radio-TLC.Then the crude product was purified by pre-activated C18 column,the final product was obtained,and the radiochemical purity of the final product was analyzed.^68Ga-NOTA-WL12 of 1.11 MBq was injected into Kunming mice through tail vein,and the in vivo distribution of the radiotracer was observed after 5,30,60,120 and 240 min,respectively.CHO-hPD-L1 tumor models with positive PD-L1 expression and MDA-MB-231 tumor models with negative PD-L1 expression were established.PET/CT was used to image the animal models at multiple time points to explore the distribution and metabolism of this molecular probe and the detection of PD-L1 in tumor lesions.Co-injection blocking experiment was carried out in CHO-hPD-L1 tumor model mice to observe the uptake of the radiotracer in the tumor.Results The labeling rate of^68Ga-NOTA-WL12 radiotracer was more than 95%,the radiochemical purity was over 98%,and the in vitro stability was good.The radiotracer was metabolized mainly through the liver and kidney,and non-specific high uptake appeared in the liver and kidney.Within 240 min,the uptake of molecular probes in tumor lesions first increased gradually,then decreased significantly.Conclusion^68Ga was convenient to label peptide NOTA-WL12,and the obtained^68Ga-NOTA-WL12 had good stability in vitro.The molecular probe could be specifically concentrated in tumor tissue in rat models with positive expression of PD-L1.

关 键 词：免疫抑制剂 正电子发射断层显像 体层摄影术 X线计算机 分子探针技术 

分 类 号：R-332[医药卫生—影像医学与核医学] R817.4[医药卫生—放射医学]