Synthesis and biological evaluation of RGD peptides with the<sup>99m</sup>Tc/<sup>188</sup>Re chelated iminodiacetate core: highly enhanced uptake and excretion kinetics of theranostics against tumor angiogenesis
作者:Byung Chul Lee、Byung Seok Moon、Ji Sun Kim、Jae Ho Jung、Hyun Soo Park、John A. Katzenellenbogen、Sang Eun Kim
DOI:10.1039/c2ra22460g
日期:——
To develop a companion set of RGD-based agents for diagnostic and radiotherapeutic purposes, facile incorporation of 99mTc(CO)3 or 188Re(CO)3 into the same precursor produced, respectively, a structurally and functionally matched radiodiagnostic and radiotherapeutic—or theranostic—pair. This work presents the synthesis of two 99mTc-labeled RGD monomers (4 and 5) along with a 99mTc-labeled RGD dimer (6) and an investigation of the influence of the small-sized and negatively charged 99mTc-iminodiacetate (IDA) core on the in vitro and in vivo behavior of these three different RGD analogs for imaging integrin αvβ3 expression. Among the three 99mTc-IDA-RGD analogs, 6 exhibited the highest integrin binding affinity with an IC50 value of 0.5 nM and a tumor uptake with an ID/g value of 12.3 ± 5.15% at 60 min post-injection, whereas liver and intestinal levels remained relatively low with good metabolic stability (>97%), presumably because of the overall negative charge of the radiometal chelating system. Both 99mTc/188Re-labeled compounds (6 and 7), which were prepared from the precursor (18), provided a good tumor accumulation and a clearly visible image of the tumor with high contrast, as compared to the contralateral background in the U87-MG xenograft model. These data support the use of 99mTc- and 188Re-IDA-D-[c(RGDfK)]2 as a matched radio-theragnostic pair that can be used to individualize radiotherapy for angiogenesis-dependent cancer.
为了开发用于诊断和放射治疗目的的 RGD 类配套制剂,将 99mTc(CO)3 或 188Re(CO)3 简单地掺入相同的前体,可分别产生结构和功能上匹配的放射诊断和放射治疗--或治疗--对。这项工作展示了两种 99mTc 标记的 RGD 单体(4 和 5)以及一种 99mTc 标记的 RGD 二聚体(6)的合成,并研究了小尺寸和带负电荷的 99mTc-iminodiacetate (IDA) 核心对这三种不同 RGD 类似物在体外和体内成像整合素 αvβ3 表达行为的影响。在三种 99mTc-IDA-RGD 类似物中,6 的整合素结合亲和力最高,IC50 值为 0.5 nM,注射后 60 分钟的肿瘤摄取 ID/g 值为 12.3 ± 5.15%,而肝脏和肠道中的含量相对较低,代谢稳定性良好(>97%),这可能是由于放射性金属螯合系统的整体负电荷。在 U87-MG 异种移植模型中,由前体(18)制备的两种 99mTc/188Re 标记化合物(6 和 7)都能提供良好的肿瘤蓄积和清晰可见的高对比度肿瘤图像。这些数据支持使用 99mTc- 和 188Re-IDA-D-[c(RGDfK)]2 作为匹配的放射-他诊断配对,可用于血管生成依赖性癌症的个体化放疗。