Radioiodinated 4-(<i>p</i>-Iodophenyl) Butanoic Acid-Modified Estradiol Derivative for ER Targeting SPECT Imaging
作者:Duo Xu、Xiaoru Lin、Xinying Zeng、Xuejun Wen、Jingchao Li、Yesen Li、Jinxiong Huang、Xiaoyuan Chen、Zhide Guo、Xianzhong Zhang
DOI:10.1021/acs.analchem.1c03616
日期:2021.10.19
Overexpression of estrogen receptors (ERs) is one of the important characteristics of most breast cancers. We aim to develop a new type of ER-specific radioiodine-labeled estrogen derivative ([131I]IPBA-EE), which was modified with an albumin-specific ligand 4-(p-iodophenyl) butyric acid (IPBA) to improve the metabolic stability and enhance the ER-targeting ability of estrogen. [131I]IPBA-EE can effectively bind to albumin in vitro, and its dissociation constant (Kd = 0.31 μM) is similar to IPBA (Kd = 0.30 μM). The uptake of [131I]IPBA-EE in ER-positive MCF-7 cells (41.81 ± 3.41%) was significantly higher than that in ER-negative MDA-MB-231 cells (8.78 ± 2.37%, ***P < 0.0005) and could be significantly blocked (3.92 ± 0.35%, ***P < 0.0005). The uptakes of [131I]IPBA-EE in rat uterus and ovaries were 5.66 ± 0.34% ID/g and 5.71 ± 2.77% ID/g, respectively, at 1 h p.i., and these uptakes could be blocked by estradiol (uterus: 2.81 ± 0.41% ID/g, *P < 0.05; ovarian: 3.02 ± 0.08% ID/g, *P < 0.05). SPECT/CT imaging showed that ER-positive MCF-7 tumor uptake of [131I]IPBA-EE reached to 6.07 ± 0.20% ID/g at 7 h p.i., which was significantly higher than that of ER-negative MDA-MB-231 tumor (0.87 ± 0.08% ID/g, **P < 0.005) and could be blocked obviously with fulvestrant (1.65 ± 1.56% ID/g, *P < 0.05). In conclusion, a novel radioiodinated estradiol derivative, [131I]IPBA-EE with albumin-binding property and good metabolic stability, was developed to image the ER in breast cancer. This promising ER-targeted probe has the potential to warrant further preclinical investigations.
雌激素受体(ER)的过度表达是大多数乳腺癌的重要特征之一。我们旨在开发一种新型ER特异性放射性碘标记雌激素衍生物([131I]IPBA-EE),该衍生物经白蛋白特异性配体4-(对碘苯基)丁酸(IPBA)修饰,可提高代谢稳定性,增强雌激素的ER靶向能力。[131I]IPBA-EE在体外能有效地与白蛋白结合,其解离常数(Kd = 0.31 μM)与IPBA(Kd = 0.30 μM)相似。ER阳性的MCF-7细胞对[131I]IPBA-EE的摄取率(41.81 ± 3.41%)明显高于ER阴性的MDA-MB-231细胞(8.78 ± 2.37%,***P < 0.0005),而且[131I]IPBA-EE的摄取可被明显阻断(3.92 ± 0.35%,***P < 0.0005)。大鼠子宫和卵巢对[131I]IPBA-EE的摄取量在1小时后分别为5.66 ± 0.34% ID/g和5.71 ± 2.77% ID/g,这些摄取量可被雌二醇阻断(子宫:2.81 ± 0.41% ID/g,*P < 0.05;卵巢:3.02 ± 0.08% ID/g,*P < 0.05)。SPECT/CT成像显示,ER阳性的MCF-7肿瘤在7小时后对[131I]IPBA-EE的摄取量达到6.07 ± 0.20% ID/g,明显高于ER阴性的MDA-MB-231肿瘤(0.87 ± 0.08% ID/g,**P < 0.005),而且氟维司群可明显阻断[131I]IPBA-EE的摄取(1.65 ± 1.56% ID/g,*P < 0.05)。总之,一种新型放射性碘化雌二醇衍生物--[131I]IPBA-EE具有白蛋白结合特性和良好的代谢稳定性,可用于乳腺癌ER的成像。这种很有前景的ER靶向探针有望得到进一步的临床前研究。