Site-specifically 89Zr-labeled monoclonal antibodies for ImmunoPET
Site-specifically 89Zr-labeled monoclonal antibodies for ImmunoPET
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DOI：
10.1016/j.nucmedbio.2009.11.010
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发表时间：
2010-04-01
影响因子：
3.1
通讯作者：
Marik, Jan
中科院分区：
文献类型：
--
作者：
Tinianow, Jeff N.;Gill, Herman S.;Marik, Jan
开发了三种巯基反应试剂，用于通过工程化半胱氨酸残基（硫代曲妥珠单抗）将去铁胺（Df）化学选择性缀合至单克隆抗体。研究了位点特异性放射性标记的Zr-89-Df-硫代-曲妥珠单抗缀合物的体外稳定性和体内成像性质。去铁胺B的氨基被溴乙酰溴、N-羟基琥珀酰亚胺基碘乙酸酯或N-羟基琥珀酰亚胺基4[N-马来酰亚胺甲基]环己烷-1-羧酸酯酰化，得到硫醇反应试剂溴乙酰基-去铁胺（Df-Bac），碘乙酰基-去铁胺（Df-Iac）和马来酰亚胺基环己基-去铁胺（Df-Chx-Mal）。Df-Bac和Df-lac通过亲核取代使硫代-曲妥珠单抗的游离巯基烷基化，形成Df-Ac-硫代-曲妥珠单抗，而马来酰亚胺试剂Df-Chx-Mal通过迈克尔加成反应，得到Df-Chx-Mal-硫代-曲妥珠单抗。结果：以14%（Df-Bac）、53%（Df-lac）和45%（Df-Chx-Mal）的产率合成了三种具有化学选择性的药物。Df-Chx-Mal与硫代曲妥珠单抗的位点特异性缀合在pH 7.5下在1小时内完成，而Df-lac和Df-Bac在pH 9下分别需要2小时和5小时。每种Df修饰的硫代曲妥珠单抗与Zr-89螯合，产率超过75%。Zr-89-Df-Ac-硫代-曲妥珠单抗和Zr-89-Df-Chx-Mal-硫代-曲妥珠单抗在小鼠血清中稳定，并且在BT474 M1中表现出相当的PET成像能力。（HER 2阳性）乳腺癌模型达到20- 25%ID/g肿瘤摄取和6.1- 7.1的肿瘤与血液比率。新试剂表现出与曲妥珠单抗的工程硫醇基团的良好反应性和与89 Zr的非常好的螯合性质。位点特异性Zr-89标记的硫代抗体在血清中是稳定的，并且显示出与赖氨酸缀合物相当的PET成像性质。(C)2010年爱思唯尔公司All rights reserved.
Three thiol reactive reagents were developed for the chemoselective conjugation of desferrioxamine (Df) to a monoclonal antibody via engineered cysteine residues (thio-trastuzumab). The in vitro stability and in vivo imaging properties of site-specifically radiolabeled Zr-89-Df-thio-trastuzumab conjugates were investigated.Methods: The amino group of desferrioxamine B was acylated by bromoacetyl bromide, N-hydroxysuccinimidyl iodoacetate, or N-hydroxysuccinimidyl 4[N-maleimidomethyl]cyclohexane-1-carboxylate to obtain thiol reactive reagents bromoacetyl-desferrioxamine (Df-Bac), iodoacetyl-desferrioxamine (Df-Iac) and maleimidocyclohexyl-desferrioxamine (Df-Chx-Mal), respectively. Df-Bac and Df-lac alkylated the free thiol groups of thio-trastuzumab by nucleophilic substitution forming Df-Ac-thio-trastuzumab, while the maleimide reagent Df-Chx-Mal reacted via Michael addition to provide Df-Chx-Mal-thio-trastuzumab. The conjugates were radiolabeled with Zr-89 and evaluated for serum stability, and their positron emission tomography (PET) imaging properties were investigated in a BT474M1 (HER2-positive) breast tumor mouse model.Results: The chemoselective reagents were obtained in 14% (Df-Bac), 53% (Df-lac) and 45% (Df-Chx-Mal) yields. Site-specific conjugation of Df-Chx-Mal to thio-trastuzumab was complete within 1 h at pH 7.5, while Df-lac and Df-Bac respectively required 2 and 5 h at pH 9. Each Df modified thio-trastuzumab was chelated with Zr-89 in yields exceeding 75%. Zr-89-Df-Ac-thio-trastuzumab and Zr-89-Df-Chx-Mal-thio-trastuzumab were stable in mouse serum and exhibited comparable PET imaging capabilities in a BT474M1 (HER2-positive) breast cancer model reaching 20-25 %ID/g of tumor uptake and a tumor to blood ratio of 6.1-7.1.Conclusions: The new reagents demonstrated good reactivity with engineered thiol groups of trastuzumab and very good chelation properties with 89Zr. The site-specifically Zr-89-labeled thio-antibodies were stable in serum and showed PET imaging properties comparable to lysine conjugates. (C) 2010 Elsevier Inc. All rights reserved.