Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences.
Department of Radiology and Nuclear Medicine, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari.
Nucl Med Commun. 2022 Aug 1;43(8):945-951. doi: 10.1097/MNM.0000000000001590. Epub 2022 Jun 27.
Imaging of glioblastoma multiform (GBM) tumor using 68 -Galium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaceticacid-Ser-Ser-Ser-Leu-Thr-Val-Ser-Pro-Trp-Tyr ( 68 Ga-DOTA-(Ser)3-LTVSPWY) as a PET radiotracer for HER2 receptor due to fact that this receptor plays a pivotal role in the tumorigenesis and tumor progression in a wide range of cancer.
68 Ga-DOTA-(Ser) 3 -LTVSPWY was produced with high radiochemical purity. The affinity and specificity of this radiotracer toward HER2 receptor on the surface of glioma glioblastoma (U-87 MG) cell line were evaluated. Furthermore, the biodistribution and PET imaging of this radiolabeled peptide were investigated on xenografted U-87 MG tumor-bearing mice.
The in-vitro specific binding study revealed that the 68 Ga-DOTA-(Ser) 3 -LTVSPWY binds to different cell lines with respect to their level of HER2 expression. The calculated K D and B max of radiolabeled peptide toward U-87 MG cell line were 5.5 ± 2.4 nmol/l and (2.4 ± 0.3) × 10 5 receptors per cell, respectively. The highest tumor uptake was observed at 30-min postinjection, whereas the tumor-to-muscle ratio was about four-fold. The acquired PET images distinctively show tumor site, which was blocked with excess nonlabeled peptide that revealed specific in-vivo targeting of 68 Ga-DOTA-(Ser) 3 -LTVSPWY for glioma.
68 Ga-DOTA-(Ser) 3 -LTVSPWY specifically recognizes HER2 receptors and could be a potential candidate for GBM imaging.
使用 68-镓-1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸-丝氨酸-丝氨酸-丝氨酸-亮氨酸-苏氨酸-缬氨酸-丝氨酸-脯氨酸-色氨酸-酪氨酸（68Ga-DOTA-（Ser）3-LTVSPWY）作为正电子发射断层扫描（PET）示踪剂，用于 HER2 受体成像，因为该受体在多种癌症的肿瘤发生和肿瘤进展中发挥关键作用。
用高放射化学纯度生产 68Ga-DOTA-（Ser）3-LTVSPWY。评估该示踪剂与胶质瘤神经胶质瘤（U-87MG）细胞系表面 HER2 受体的亲和力和特异性。此外，还研究了该放射性标记肽在荷瘤 U-87MG 肿瘤的异种移植小鼠中的生物分布和 PET 成像。
体外特异性结合研究表明，68Ga-DOTA-（Ser）3-LTVSPWY 与不同细胞系结合，与它们的 HER2 表达水平有关。放射性标记肽对 U-87MG 细胞系的计算 K D和 B max分别为 5.5±2.4nmol/L 和（2.4±0.3）×10 5个受体/细胞。注射后 30 分钟观察到肿瘤摄取最高，而肿瘤与肌肉的比值约为四倍。获得的 PET 图像清晰地显示了肿瘤部位，用过量的未标记肽阻断后，肿瘤部位明显显示出 68Ga-DOTA-（Ser）3-LTVSPWY 对神经胶质瘤的特异性体内靶向。
68Ga-DOTA-（Ser）3-LTVSPWY 特异性识别 HER2 受体，可能是神经胶质瘤成像的潜在候选物。
