Mohammadgholi Mohsen, Sadeghzadeh Nourollah, Erfani Mostafa, Abediankenari Saeid, Abedi Seyed Mohammad, Emrarian Iman, Jafari Narjes, Behzadi Ramezan
Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran.
Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran (AEOI), Tehran, Iran.
Anticancer Agents Med Chem. 2018;18(2):277-285. doi: 10.2174/1871520617666170918125020.
Human fibronectin extra-domain B (EDB) is particularly expressed during angiogenesis progression. It is, thus, a promising marker of tumour growth. Aptides are a novel class of peptides with high-affinity binding to specific protein targets. APTEDB is an antagonist-like ligand that especially interacts with human fibronectin EDB.
This study was the first attempt in which the hydrazinonicotinamide (HYNIC)-conjugated APTEDB was labelled with technetium-99m (99mTc) as an appropriate radiotracer and tricine/EDDA exchange labeling.
Radiochemical purity, normal saline, and serum stability were evaluated by HPLC and radio-isotope TLC scanner. Other examinations, such as protein-binding calculation, dissociation radioligand binding assay, and partition coefficient constant determination, were also carried out. The cellular-specific binding of 99mTc- HYNIC-conjugated APTEDB was assessed in two EDB-positive (U87MG) and EDB-negative (U373MG) cell lines. Bio-distribution was investigated in normal mice as well as in U87MG and U373MG tumour-bearing mice. Eventually, the radiolabelled APTEDB was used for tumour imaging using planar SPECT.
Radiolabelling was achieved with high purity (up to 97%) and accompanied by high solution (over 90% after overnight) and serum (80% after 2 hours) stability. The obtained cellular-specific binding ratio was greater than nine-fold. In-vivo experiments showed rapid blood clearance with mainly renal excretion and tumour uptake specificity (0.48±0.03% ID/g after 1h). The results of the imaging also confirmed considerable tumour uptake for EDB-positive cell line compared with the EDB-negative one.
Aptides are considered to be a potent candidate for biopharmaceutical applications. They can be modified with imaging or therapeutic agents. This report shows the capability of 99mTc-HYNIC-APTEDB for human EDB-expressing tumours detection.
人纤连蛋白额外结构域B（EDB）在血管生成进展过程中特异性表达。因此，它是一种很有前景的肿瘤生长标志物。A肽是一类新型肽，能与特定蛋白质靶点高亲和力结合。APTEDB是一种类似拮抗剂的配体，尤其与人纤连蛋白EDB相互作用。
本研究首次尝试用99m锝（99mTc）标记肼基烟酰胺（HYNIC）偶联的APTEDB作为合适的放射性示踪剂，并进行三羟甲基氨基甲烷/乙二胺二乙酸（tricine/EDDA）交换标记。
通过高效液相色谱（HPLC）和放射性同位素薄层色谱扫描仪评估放射化学纯度、生理盐水稳定性和血清稳定性。还进行了其他检测，如蛋白结合计算、解离放射性配体结合试验和分配系数常数测定。在两种EDB阳性（U87MG）和EDB阴性（U373MG）细胞系中评估99mTc-HYNIC偶联的APTEDB的细胞特异性结合。在正常小鼠以及U87MG和U373MG荷瘤小鼠中研究生物分布。最后，使用平面单光子发射计算机断层扫描（SPECT）将放射性标记的APTEDB用于肿瘤成像。
实现了高纯度（高达97%）的放射性标记，同时具有高溶液稳定性（过夜后超过90%）和血清稳定性（2小时后80%）。获得的细胞特异性结合率大于9倍。体内实验表明血液清除迅速，主要经肾脏排泄，且具有肿瘤摄取特异性（1小时后为0.48±0.03%注射剂量/克）。成像结果也证实，与EDB阴性细胞系相比，EDB阳性细胞系的肿瘤摄取量可观。
A肽被认为是生物制药应用的有力候选物。它们可以用成像或治疗剂进行修饰。本报告显示了99mTc-HYNIC-APTEDB用于检测人EDB表达肿瘤的能力。
