Evaluation of a Maleimido Derivative of NOTA for Site-Specific Labeling of Affibody Molecules
Evaluation of a Maleimido Derivative of NOTA for Site-Specific Labeling of Affibody Molecules
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DOI：
10.1021/bc100470x
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发表时间：
2011-05-01
影响因子：
4.7
通讯作者：
Orlova, Anna
中科院分区：
文献类型：
--
作者：
Tolmachev, Vladimir;Altai, Mohamed;Orlova, Anna
放射性核素分子成像有可能通过选择患者进行靶向治疗来改善癌症治疗。 Affibody 分子是一类小型 (7 kDa) 高亲和力靶向蛋白，具有作为分子成像探针的巨大潜力。 NOTA 螯合剂与许多适用于 SPECT 或 PET 成像的放射性核素形成稳定的复合物。马来酰亚胺乙基单酰胺 NOTA (MMA-NOTA) 已被制备用于具有独特 C 末端半胱氨酸的 Affibody 分子的位点特异性标记。 MMA-NOTA 与抗 HER2 Affibody 分子 Z(HER2:239S) 的偶联产生了对 HER2 亲和力（解离常数）为 72 pM 的缀合物。用 In-111 标记 [MMA-NOTA-Cys(61)]-Z(HER2:239S)，在 60 摄氏度下 20 分钟后，产率 >95%。体外细胞测试证明 [In-111-MMA-NOTA-Cys(61)]-Z(HER2:239S) 与表达 HER2 的细胞系特异性结合。在携带前列腺癌 DU-145 异种移植物的小鼠中，[In-111-MMA-NOTA-Cys(61)]-Z(HER2:239S) 的肿瘤摄取为 8.2 +/- 0.9% IA/g，肿瘤与血液的比率为 31 +/- 1（注射后 4 小时）。 DU-145 异种移植物通过伽马相机清晰可见。 [In-111-MMA-NOTA-Cys(61)]-Z(HER2:239S) 和 [In-111-MMA-DOTA-Cys(61)]-Z(HER2:239S) 的直接体内比较表明，两种缀合物在肿瘤中提供相同的放射性摄取，但肿瘤与器官的比率更好[In-111-MMA-NOTA-Cys(61)]-Z(HER2:239S) 由于更有效地从正常组织中清除。总之，MMA-NOTA 与含有半胱氨酸的 Affibody 分子偶联产生了位点特异性标记的缀合物，该缀合物保留了高亲和力，可以有效标记，并允许高对比度成像。
Radionuclide molecular imaging has the potential to improve cancer treatment by selection of patients for targeted therapy. Affibody molecules are a class of small (7 kDa) high-affinity targeting proteins with appreciable potential as molecular imaging probes. The NOTA chelator forms stable complexes with a number of radionuclides suitable for SPECT or PET imaging. A maleimidoethylmonoamide NOTA (MMA-NOTA) has been prepared for site-specific labeling of Affibody molecules having a unique C-terminal cysteine. Coupling of the MMA-NOTA to the anti-HER2 Affibody molecule Z(HER2:239S) resulted in a conjugate with an affinity (dissociation constant) to HER2 of 72 pM. Labeling of [MMA-NOTA-Cys(61)]-Z(HER2:239S) with In-111 gave a yield of >95% after 20 min at 60 degrees C. In vitro cell tests demonstrated specific binding of [In-111-MMA-NOTA-Cys(61)]-Z(HER2:239S) to HER2-expressing cell lines. In mice bearing prostate cancer DU-145 xenografts, the tumor uptake of [In-111-MMA-NOTA-Cys(61)]-Z(HER2:239S) was 8.2 +/- 0.9% IA/g and the tumor-to-blood ratio was 31 +/- 1 (4 h postinjection). DU-145 xenografts were clearly visualized by a gamma camera. Direct in vivo comparison of [In-111-MMA-NOTA-Cys(61)]-Z(HER2:239S) and [In-111-MMA-DOTA-Cys(61)]-Z(HER2:239S) demonstrated that both conjugates provided equal radioactivity uptake in tumors, but the tumor-to-organ ratios were better for [In-111-MMA-NOTA-Cys(61)]-Z(HER2:239S) due to more efficient clearance from normal tissues. In conclusion, coupling of MMA-NOTA to a cysteine-containing Affibody molecule resulted in a site-specifically labeled conjugate, which retains high affinity, can be efficiently labeled, and allows for high-contrast imaging.