Metabolism and renal clearance of 111In-labeled DOTA-conjugated antibody fragments
Metabolism and renal clearance of 111In-labeled DOTA-conjugated antibody fragments
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DOI：
10.1021/bc0000987
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发表时间：
2001-03-01
影响因子：
4.7
通讯作者：
Shively, JE
中科院分区：
文献类型：
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作者：
Tsai, SW;Li, L;Shively, JE
放射性核素标记的抗体片段由于其高肿瘤摄取和快速的药代动力学而成为用于放射免疫治疗的有前途的试剂，但其治疗潜力受到肾脏中的高摄取和保留的限制。代谢产物的鉴定是设计降低肾脏摄取的合理方法的第一步。先前在大鼠中的研究表明，In-111标记的DTPA缀合抗体片段（通过赖氨酸残基）降解为DTPA-是-氨基-赖氨酸衍生物的一种元素，并保留在肝脏和肾脏的溶酶体隔室中[Rogers等人（1995）Cancer Res.55，5714 s-5720 s]。为了确定另一种广泛使用的金属螯合物的代谢特征，[In-111]DOTA通过活性酯化学与抗体片段中的赖氨酸缀合，我们分析了注射了由抗淋巴瘤完整抗体Rituxan酶促产生的[In-111]DOTA-Fab的裸鼠的肾匀浆。通过与真实的合成标准品进行比较，确定主要肾脏代谢物为[In-111] DOTA-是-氨基-赖氨酸的一种元素。在尿液中也发现了该终产物，沿着有相对少量的[In-111]DOTA-Fab。由于将[In-111] DOTA-是-氨基-赖氨酸的一种元素注射到裸鼠体内导致快速清除到尿液中而没有肾滞留，因此观察到的肾滞留可能是由于[In-111]DOTA-Fab的肾摄取，随后溶酶体降解为[In-111] DOTA-是-氨基-赖氨酸的一种元素，其仅从该隔室缓慢清除。肾脏放射自显影照片支持这一观察结果，显示放射性快速定位于肾皮质远端区域。为了将该分析扩展到临床试验，我们还分析了从注射完整抗体[In-111] DOTA-cT 84.66的患者采集的尿液。在这个例子中，我们发现，主要的放射性物种也是[In-111] DOTA-是一个元素的-氨基-赖氨酸。
Radiometal-labeled antibody fragments are promising reagents for radioimmunotherapy due to their high tumor uptake and rapid pharmacokinetics, but their therapeutic potentials are limited by high uptake and retention in the kidney. Identification of metabolic products is a first step in designing rationale approaches to lower kidney uptake. Previous studies in rats have shown that In-111-labeled DTPA-conjugated antibody fragments (via lysine residues) were degraded to an DTPA-is an element of -amino-lysine derivative and retained in the lysosomal compartments of the liver and kidney [Rogers et al. (1995) Cancer Res. 55, 5714s-5720s]. To determine the metabolic profile of another widely used metal-chelate, [In-111]DOTA conjugated to lysines in antibody fragments via active ester chemistry, we analyzed kidney homogenates from nude mice injected with an [In-111]DOTA-Fab generated enzymatically from the anti-lymphoma intact antibody Rituxan. The major kidney metabolite was identified as [In-111]DOTA-is an element of -amino-lysine by comparison to an authentic synthetic standard. This end product was also identified in the urine, along with relatively small amounts of [In-111]DOTA-Fab. Since injection of [In-111] DOTA-is an element of -amino-lysine into nude mice resulted in rapid clearance into the urine without kidney retention, it is likely that the renal retention observed was due to kidney uptake of [In-111]DOTA-Fab, followed by lysosomal degradation to [In-111]DOTA-is an element of -amino-lysine, which is only slowly cleared from this compartment. This observation is supported by autoradiographs of the kidney showing rapid localization of radioactivity into the distal regions of the kidney cortex. To extend this analysis to clinical trials, we have also analyzed urine taken from a patient injected with the intact antibody [In-111] DOTA-cT84.66. In that example, we found that the major radioactive species was also [In-111] DOTA-is an element of -amino-lysine.