Construction of Anti-hPD-L1 HCAb Nb6 and in Situ 124I Labeling for Noninvasive Detection of PD-L1 Expression in Human Bone Sarcoma
Construction of Anti-hPD-L1 HCAb Nb6 and in Situ 124I Labeling for Noninvasive Detection of PD-L1 Expression in Human Bone Sarcoma
复制标题
抗 hPD-L1 HCAb Nb6 的构建和原位 I-124 标记用于无创检测人骨肉瘤中 PD-L1 的表达
DOI：
10.1021/acs.bioconjchem.9b00539
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发表时间：
2019-10-01
影响因子：
4.7
通讯作者：
Yang, Zhi
中科院分区：
文献类型：
--
作者：
Huang, Hai-Feng;Zhu, Hua;Yang, Zhi
免疫疗法被认为是仅次于手术、化疗和放射治疗的第四种主要癌症治疗方式。近年来，肿瘤免疫治疗取得了突破性进展，因此，对患者进行筛查以确定哪些患者对肿瘤免疫治疗有反应是非常重要的。在这里，我们报道了一种新型的仅重链抗体(HCAb)的构建及其相应的I-124标记的探针。利用噬菌体展示技术，我们从95个克隆中筛选出与HPD-L1具有高亲和力的新型抗HPD-L1特异性HCAb Nb6。制备了正电子发射I-124标记的HPD-L1靶向HCAb探针，并合成了非放射性天然碘(I-NAT)标记的抗HPD-L1 Nb6作为参考化合物。该前体可阻断OS-732细胞对I-125-抗HPD-L1Nb6的摄取。I-125-抗HPD-L1NB6与OS-732细胞的结合亲和力为2.19 nM。对于体内研究，成功地构建了骨肉瘤OS-732荷瘤小鼠模型。聚合酶链式反应和Western印迹分析证实HPD-L1基因和抗原在OS-732小鼠模型肿瘤组织中的存在。生物分布显示，I-124-抗HPD-L1Nb6探针在OS-732肿瘤组织中的摄取率为4.43+/-0.33%ID/g。注射I-124-抗HPD-L1Nb6后24小时，微电子发射断层扫描/计算机断层扫描可清楚显示肿瘤病变，而阻断组显着减少摄取。病理染色证实HPD-L1在肿瘤细胞膜表面有表达，因此I-124-抗HPD-L1NB6可用于体内无创PET成像。当NB6和I-124-抗HPD-L1NB6联合应用时，可能会提供一种新的策略，用于临床筛查HPD-L1患者，以确定哪些人将从骨肉瘤等恶性肿瘤的免疫治疗中受益。
Immunotherapy is considered the fourth major treatment mode for cancer following surgery, chemotherapy, and radiotherapy. In recent years, tumor immunotherapy has achieved breakthrough progress; therefore, it is important to screen patients to identify those who will respond to tumor immunotherapy. Here, we report the construction of a novel heavy chain-only antibody (HCAb) and its corresponding I-124-labeled probe. Using phage display technology, we generated a novel anti-hPD-L1-specific HCAb named Nb6 (selected from 95 monoclones) with high affinity for hPD-L1. The positron emitting I-124-labeled hPD-L1-targeted HCAb probe was prepared for further evaluation, and nonradioactive natural iodine (I-nat)-labeled anti-hPD-L1 Nb6 was synthesized as a reference compound. I-125-anti-hPD-L1 Nb6 uptake in OS-732 cells in vitro can be blocked by the precursor. The binding affinity of I-125-anti-hPD-L1 Nb6 to OS-732 cell lines was 2.19 nM. For in vivo studies, an osteosarcoma OS-732 tumor-bearing mouse model was successfully constructed. Polymerase chain reaction (PCR) and Western blot analyses were performed to confirm the presence of the hPD-L1 gene and antigen in the tumor tissue of the OS-732 mouse model. Biodistribution showed that uptake of I-124-anti-hPD-L1 Nb6 probes at 24 h was 4.43 +/- 0.33% ID/g in OS-732 tumor tissues. Tumor lesions can be clearly delineated on micro-PET (positron emission tomography)/CT (computed tomography) imaging 24 h after injection of I-124-anti-hPD-L1 Nb6, while the blocking group shows substantially decreased uptake on imaging. Pathological staining validated hPD-L1 expression on the surface of the tumor cell membrane; thus, I-124-anti-hPD-L1 Nb6 can be used for in vivo noninvasive PET imaging. When administered in tandem, Nb6 and I-124-anti-hPD-L1 Nb6 may provide a novel strategy to clinically screen patients for hPD-L1 to identify those who would benefit from immunotherapy of malignant tumors such as osteosarcoma.